crates/oxy-core/src/repo/tests.rs at 9b761fe2f751 · andymccall/oxygen

# 9b761fe2f751 oxygen / crates / oxy-core / src / repo / tests.rs
141.8 KiB · Rust · last changed Unbound hosted repositories adopt the first pusher's id 1 month ago source blame history raw
//! Tests for the repository layer.

use super::*;
use crate::protocol::SignedPolicy;
use crate::repo::{BisectStep, Selection};

/// Point `$OXY_HOME` at a throwaway directory once per test process so no
/// test reads or writes the developer's real user configuration or keys.
fn hermetic() {
    static ONCE: std::sync::Once = std::sync::Once::new();
    static DIR: std::sync::OnceLock<tempfile::TempDir> = std::sync::OnceLock::new();
    ONCE.call_once(|| {
        let d = tempfile::tempdir().unwrap();
        std::env::set_var("OXY_HOME", d.path());
        DIR.set(d).ok();
    });
}

fn write(root: &Path, rel: &str, content: &[u8]) {
    let p = root.join(rel);
    fs::create_dir_all(p.parent().unwrap()).unwrap();
    fs::write(p, content).unwrap();
}

fn statuses(s: &SnapshotResult) -> Vec<(String, ChangeStatus)> {
    s.statuses
        .iter()
        .map(|p| (p.path.clone(), p.status))
        .collect()
}

#[test]
fn init_snapshot_commit_log_undo() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap();
    assert!(Repo::init(root).is_err());
    let ops = repo.op_log().unwrap();
    assert_eq!(ops.len(), 1);
    assert_eq!(ops[0].1.command, "oxy init");

    // Empty working copy: snapshot records no operation (spec §12.3).
    let s = repo.snapshot("oxy status").unwrap();
    assert!(!s.changed);
    assert_eq!(repo.op_log().unwrap().len(), 1);

    write(root, "src/main.rs", b"fn main() {}\n");
    write(root, "README.md", b"# Hello\n");
    write(root, ".oxyignore", b"/target\n");
    write(root, "target/junk.o", b"\0\0\0");
    let s = repo.snapshot("oxy status").unwrap();
    assert!(s.changed);
    assert_eq!(
        statuses(&s),
        vec![
            (".oxyignore".into(), ChangeStatus::Added),
            ("README.md".into(), ChangeStatus::Added),
            ("src/main.rs".into(), ChangeStatus::Added),
        ]
    );
    assert_eq!(repo.op_log().unwrap().len(), 2);
    // Snapshotting again with nothing changed records no op.
    let s2 = repo.snapshot("oxy status").unwrap();
    assert!(!s2.changed);
    assert_eq!(s2.wc_hash, s.wc_hash);
    assert_eq!(repo.op_log().unwrap().len(), 2);

    let h1 = repo.commit("Initial import", &[]).unwrap();
    let c1 = repo.store().get_change(&h1).unwrap();
    assert_eq!(c1.kind, ChangeKind::Normal);
    assert!(c1.deps.is_empty(), "first change has nothing to depend on");
    assert_eq!(repo.bookmark_heads().unwrap(), vec![h1]);
    let (wc_hash, wc) = repo.working_copy().unwrap();
    assert_eq!(wc.deps, vec![h1]);
    assert!(wc.edits.is_empty());
    assert!(repo.commit("nothing", &[]).is_err());

    // Modify one file, remove another, add a binary file.
    write(
        root,
        "src/main.rs",
        b"fn main() {\n    println!(\"hi\");\n}\n",
    );
    fs::remove_file(root.join("README.md")).unwrap();
    write(root, "logo.png", b"\x89PNG\0\0\x01");
    let s = repo.snapshot("oxy status").unwrap();
    assert_eq!(
        statuses(&s),
        vec![
            ("README.md".into(), ChangeStatus::Removed),
            ("logo.png".into(), ChangeStatus::Added),
            ("src/main.rs".into(), ChangeStatus::Modified),
        ]
    );
    assert_ne!(s.wc_hash, wc_hash);
    // The rewritten working copy keeps its ChangeId and depends on h1.
    assert_eq!(s.wc.change_id, wc.change_id);
    assert!(s.wc.deps.contains(&h1));

    let h2 = repo.commit("Second", &[]).unwrap();
    let c2 = repo.store().get_change(&h2).unwrap();
    assert_eq!(
        c2.deps,
        vec![h1],
        "everything it touches was introduced by h1"
    );
    assert_eq!(repo.bookmark_heads().unwrap(), vec![h2]);

    // The materialized head state matches the working copy.
    let st = repo.load_state(&[h2]).unwrap();
    let snap = st.materialize();
    assert!(!snap.is_conflicted());
    assert_eq!(
        snap.files.keys().cloned().collect::<Vec<_>>(),
        [".oxyignore", "logo.png", "src", "src/main.rs"]
    );
    assert!(
        matches!(&snap.files["src/main.rs"].content, FileContent::Text { bytes, .. } if bytes == b"fn main() {\n    println!(\"hi\");\n}\n")
    );
    assert!(snap.files["logo.png"].mode.opaque);
    if let FileContent::Opaque { blobs } = &snap.files["logo.png"].content {
        assert_eq!(repo.read_blob(&blobs[0]).unwrap(), b"\x89PNG\0\0\x01");
    } else {
        panic!("logo should be opaque");
    }

    // Log: newest first, working copy included.
    let log = repo.log().unwrap();
    assert_eq!(log.len(), 3);
    assert!(log[0].is_working_copy);
    assert_eq!(log[1].hash, h2);
    assert!(log[1].is_head);
    assert_eq!(log[2].hash, h1);
    let d = repo.describe_change(&h2).unwrap();
    assert!(d.contains("D README.md"), "{d}");
    assert!(d.contains("+    println!(\"hi\");"), "{d}");
    assert!(d.contains("-fn main() {}"), "{d}");

    // Resolution by prefix.
    assert_eq!(repo.resolve_change(&c2.change_id.short(6)).unwrap(), h2);
    assert_eq!(
        repo.resolve_change(&format!("#{}", h1.short(8))).unwrap(),
        h1
    );
    assert!(repo.resolve_change("zzzz").is_err());

    // Undo the commit: bookmark and working copy go back.
    repo.undo().unwrap();
    assert_eq!(repo.bookmark_heads().unwrap(), vec![h1]);
    let s = repo.snapshot("oxy status").unwrap();
    assert!(
        !s.changed,
        "files on disk still match the pre-commit working copy"
    );
    assert_eq!(s.statuses.len(), 3);
}

/// Make `main` conflicted: two commits on the same base that edit the same line.
fn conflicted_repo() -> (tempfile::TempDir, Repo, ChangeHash, ChangeHash, ChangeHash) {
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap();
    write(root, "f.txt", b"a\nb\nc\n");
    let h1 = repo.commit("base", &[]).unwrap();
    write(root, "f.txt", b"a\nB\nc\n");
    let h2 = repo.commit("upper", &[]).unwrap();
    repo.checkout(&[h1], false, "checkout").unwrap();
    write(root, "f.txt", b"a\nX\nc\n");
    let h3 = repo.commit("ex", &[]).unwrap();
    (dir, repo, h1, h2, h3)
}

#[test]
fn concurrent_edits_conflict_and_can_be_resolved() {
    hermetic();
    let (dir, repo, h1, h2, h3) = conflicted_repo();
    let root = dir.path();
    let heads: BTreeSet<_> = repo.bookmark_heads().unwrap().into_iter().collect();
    assert_eq!(heads, [h2, h3].into_iter().collect());
    let st = repo.load_state(&[h2, h3]).unwrap();
    assert!(st.materialize().is_conflicted());

    // Checking out main writes markers.
    let r = repo
        .checkout(&repo.bookmark_heads().unwrap(), false, "checkout main")
        .unwrap();
    assert!(r.conflicted);
    let marked = fs::read_to_string(root.join("f.txt")).unwrap();
    assert!(
        marked.starts_with("a\n<<<<<<< oxy conflict 1 of 1"),
        "{marked}"
    );
    assert!(
        marked.contains("B\n") && marked.contains("X\n") && marked.ends_with("end\nc\n"),
        "{marked}"
    );
    assert!(has_conflict_markers(marked.as_bytes()));
    // Untouched markers: clean working copy; commit has nothing to do.
    let s = repo.snapshot("status").unwrap();
    assert!(s.statuses.is_empty());
    assert!(!s.resolves);

    // Partially edited file that still has markers cannot be committed.
    write(root, "f.txt", marked.replace("B\n", "BB\n").as_bytes());
    let s = repo.snapshot("status").unwrap();
    assert_eq!(
        statuses(&s),
        vec![("f.txt".into(), ChangeStatus::ConflictEdited)]
    );
    assert!(repo.commit("no", &[]).is_err());

    // Resolve by keeping one side and adding a line elsewhere.
    write(root, "f.txt", b"a\nX\nc\nd\n");
    let s = repo.snapshot("status").unwrap();
    assert_eq!(statuses(&s), vec![("f.txt".into(), ChangeStatus::Resolved)]);
    assert!(s.resolves);
    let h4 = repo.commit("resolve", &[]).unwrap();
    let c4 = repo.store().get_change(&h4).unwrap();
    assert_eq!(c4.kind, ChangeKind::Resolution);
    let mut want = vec![h1, h2, h3];
    want.sort();
    assert_eq!(
        c4.deps, want,
        "a resolution depends on exactly the contributors and what it references"
    );
    assert_eq!(repo.bookmark_heads().unwrap(), vec![h4]);
    let snap = repo.load_state(&[h4]).unwrap().materialize();
    assert!(!snap.is_conflicted());
    assert!(
        matches!(&snap.files["f.txt"].content, FileContent::Text { bytes, .. } if bytes == b"a\nX\nc\nd\n")
    );
    assert!(!repo.snapshot("status").unwrap().changed);
    // A peer holding only h2 and h3 and receiving h4 sees the same result,
    // whatever order the changes arrive in.
    let mut st = State::new();
    for h in [h4, h3, h1, h2] {
        st.add_unchecked(repo.store().get_change(&h).unwrap());
    }
    st.validate().unwrap();
    assert!(
        matches!(&st.materialize().files["f.txt"].content, FileContent::Text { bytes, .. } if bytes == b"a\nX\nc\nd\n")
    );
}

#[test]
fn resolution_may_keep_both_sides_or_neither() {
    hermetic();
    let (dir, repo, _h1, _h2, _h3) = conflicted_repo();
    let root = dir.path();
    repo.checkout(&repo.bookmark_heads().unwrap(), false, "checkout main")
        .unwrap();
    // Keep both sides in a chosen order.
    write(root, "f.txt", b"a\nX\nB\nc\n");
    let h = repo.commit("both", &[]).unwrap();
    let snap = repo.load_state(&[h]).unwrap().materialize();
    assert!(!snap.is_conflicted());
    assert!(
        matches!(&snap.files["f.txt"].content, FileContent::Text { bytes, .. } if bytes == b"a\nX\nB\nc\n")
    );
    // Undo and instead drop the whole region.
    repo.undo().unwrap();
    write(root, "f.txt", b"a\nc\n");
    let h = repo.commit("neither", &[]).unwrap();
    let snap = repo.load_state(&[h]).unwrap().materialize();
    assert!(!snap.is_conflicted());
    assert!(
        matches!(&snap.files["f.txt"].content, FileContent::Text { bytes, .. } if bytes == b"a\nc\n")
    );
}

#[test]
fn name_conflict_resolved_by_removing_a_candidate() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap();
    write(root, "keep.txt", b"k\n");
    let h1 = repo.commit("base", &[]).unwrap();
    write(root, "new.txt", b"one\n");
    repo.commit("one", &[]).unwrap();
    repo.checkout(&[h1], false, "checkout").unwrap();
    write(root, "new.txt", b"two\n");
    repo.commit("two", &[]).unwrap();
    let r = repo
        .checkout(&repo.bookmark_heads().unwrap(), false, "checkout main")
        .unwrap();
    assert!(r.conflicted);
    assert!(
        root.join("new.txt.oxy-conflict-1").exists()
            && root.join("new.txt.oxy-conflict-2").exists()
    );
    assert!(!root.join("new.txt").exists());
    // Candidate numbering follows change-hash order, so pick by content:
    // keep the "two" candidate under the real name and drop the other.
    let (keep, drop) = if fs::read(root.join("new.txt.oxy-conflict-1")).unwrap() == b"two\n" {
        (1, 2)
    } else {
        (2, 1)
    };
    fs::remove_file(root.join(format!("new.txt.oxy-conflict-{drop}"))).unwrap();
    fs::rename(
        root.join(format!("new.txt.oxy-conflict-{keep}")),
        root.join("new.txt"),
    )
    .unwrap();
    let h = repo.commit("pick two", &[]).unwrap();
    assert_eq!(
        repo.store().get_change(&h).unwrap().kind,
        ChangeKind::Resolution
    );
    // The resolution does not touch keep.txt, so it does not depend on h1;
    // the bookmark keeps both as heads and their union is the state.
    let heads: BTreeSet<_> = repo.bookmark_heads().unwrap().into_iter().collect();
    assert_eq!(heads, [h1, h].into_iter().collect());
    let snap = repo
        .load_state(&repo.bookmark_heads().unwrap())
        .unwrap()
        .materialize();
    assert!(!snap.is_conflicted(), "{:?}", snap.tree.conflicts);
    assert_eq!(
        snap.files.keys().cloned().collect::<Vec<_>>(),
        ["keep.txt", "new.txt"]
    );
    assert!(
        matches!(&snap.files["new.txt"].content, FileContent::Text { bytes, .. } if bytes == b"two\n")
    );
}

#[test]
fn identities_and_signed_commits() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let mut repo = Repo::init(root).unwrap().with_home(root.join("home"));
    write(root, "a.txt", b"a\n");
    let h0 = repo.commit("unsigned", &[]).unwrap();
    assert_eq!(repo.verify_change(&h0).unwrap(), SignatureStatus::Unsigned);
    assert_eq!(
        repo.store().get_change(&h0).unwrap().author,
        ObjectRef::ZERO
    );

    let (key, id) = repo
        .create_identity("Ada", "[email protected]", IdentityScope::Repo)
        .unwrap();
    assert_eq!(id.hash(), key);
    assert_eq!(repo.config.author_key, Some(key));
    // Config survives reopen; the secret key is found again.
    let reopened = Repo::open(root).unwrap().with_home(root.join("home"));
    assert_eq!(reopened.config.author_key, Some(key));
    assert_eq!(reopened.secret_key().unwrap().unwrap().0, key);

    // Default core.sign = seal: commits carry the author but no signature.
    write(root, "a.txt", b"a\nb\n");
    let h1 = repo.commit("authored", &[]).unwrap();
    assert_eq!(repo.store().get_change(&h1).unwrap().author, key);
    assert_eq!(repo.verify_change(&h1).unwrap(), SignatureStatus::Unsigned);
    // Signing later works too.
    repo.sign_change(&h1).unwrap();
    assert!(
        matches!(repo.verify_change(&h1).unwrap(), SignatureStatus::Valid { key: k, .. } if k == key)
    );

    repo.config.set("core.sign", "change").unwrap();
    repo.save_config().unwrap();
    write(root, "a.txt", b"a\nb\nc\n");
    let h2 = repo.commit("signed", &[]).unwrap();
    assert_eq!(
        repo.verify_change(&h2).unwrap(),
        SignatureStatus::Valid {
            key,
            name: "Ada".into(),
            email: "[email protected]".into(),
            sealed: false,
            revoked: false
        }
    );

    // A signature by a key that is not the author or a delegate is rejected.
    let other = SecretKey::generate();
    let other_id = other.identity("Mallory", "[email protected]", 0);
    let other_key = repo.store().put_identity(&other_id).unwrap();
    let forged = other.sign(Domain::Change, &other_key, &h0);
    repo.store().put_signature(&h0, &forged).unwrap();
    assert!(
        matches!(repo.verify_change(&h0).unwrap(), SignatureStatus::Invalid(m) if m.contains("neither the author"))
    );

    // Tampering with the stored signature invalidates it.
    let mut sig = repo.store().signatures(&h2).unwrap().remove(0);
    sig.ed[0] ^= 1;
    repo.store().put_signature(&h2, &sig).unwrap();
    assert!(matches!(
        repo.verify_change(&h2).unwrap(),
        SignatureStatus::Invalid(_)
    ));

    // Without the secret key, signing at commit fails cleanly.
    let no_keys = Repo::open(root).unwrap().with_home(root.join("nowhere"));
    write(root, "a.txt", b"z\n");
    assert!(no_keys.commit("cannot sign", &[]).is_err());
}

#[test]
fn checkout_moves_the_working_copy() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap();
    write(root, "a.txt", b"one\n");
    write(root, "sub/deep/b.txt", b"b\n");
    let h1 = repo.commit("first", &[]).unwrap();
    write(root, "a.txt", b"two\n");
    fs::remove_file(root.join("sub/deep/b.txt")).unwrap();
    write(root, "bin.dat", &[0, 1, 2, 3]);
    let h2 = repo.commit("second", &[]).unwrap();

    let r = repo.checkout(&[h1], false, "oxy checkout").unwrap();
    assert_eq!(
        r,
        CheckoutReport {
            written: 2,
            removed: 1,
            conflicted: false,
            notes: vec![]
        }
    );
    assert_eq!(fs::read(root.join("a.txt")).unwrap(), b"one\n");
    assert_eq!(fs::read(root.join("sub/deep/b.txt")).unwrap(), b"b\n");
    assert!(!root.join("bin.dat").exists());
    let (_, wc) = repo.working_copy().unwrap();
    assert_eq!(wc.deps, vec![h1]);
    assert!(
        !repo.snapshot("status").unwrap().changed,
        "checkout leaves a clean working copy"
    );
    // The bookmark still points at h2.
    assert_eq!(repo.bookmark_heads().unwrap(), vec![h2]);

    // Dirty working copy refuses without --discard.
    write(root, "a.txt", b"dirty\n");
    assert!(repo.checkout(&[h2], false, "oxy checkout").is_err());
    let r = repo
        .checkout(&[h2], true, "oxy checkout --discard")
        .unwrap();
    assert_eq!(fs::read(root.join("a.txt")).unwrap(), b"two\n");
    assert_eq!(fs::read(root.join("bin.dat")).unwrap(), [0, 1, 2, 3]);
    assert!(!root.join("sub").exists(), "empty directories are pruned");
    assert_eq!(r.removed, 1);
    assert!(!repo.snapshot("status").unwrap().changed);

    // Refuses to write through a symlinked directory.
    #[cfg(unix)]
    {
        fs::remove_dir_all(root.join("sub")).ok();
        std::os::unix::fs::symlink("/tmp", root.join("sub")).unwrap();
        assert!(repo.checkout(&[h1], true, "oxy checkout").is_err());
    }
}

#[test]
fn large_files_are_chunked_and_read_back() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let repo = Repo::init(dir.path()).unwrap();
    let mut big = vec![0u8; 700 * 1024];
    for (i, b) in big.iter_mut().enumerate() {
        *b = (i as u32).wrapping_mul(2654435761).to_le_bytes()[0];
    }
    let r = repo.store_blob(&big).unwrap();
    let blob = Blob::decode(&repo.store().get_typed(&r, ObjectType::Blob).unwrap()).unwrap();
    assert!(blob.chunks.len() >= 3, "{}", blob.chunks.len());
    assert_eq!(repo.read_blob(&r).unwrap(), big);
    assert_eq!(Repo::blob_ref(&big), r);
}

#[test]
fn clone_push_pull_with_seals_and_attestations() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let origin_path = root.join("origin");
    let origin = Repo::init(&origin_path).unwrap();
    let origin_url = origin_path.to_string_lossy().to_string();

    // A clones, creates an identity (default core.sign = seal), commits, pushes.
    let mut a = Repo::clone(&origin_url, &root.join("a"))
        .unwrap()
        .with_home(root.join("home-a"));
    assert_eq!(a.id().unwrap(), origin.id().unwrap());
    let (key_a, _) = a
        .create_identity("Ada", "[email protected]", IdentityScope::Repo)
        .unwrap();
    write(&root.join("a"), "f.txt", b"a\n");
    let h1 = a.commit("first", &[]).unwrap();
    let results = a.push("origin", false).unwrap();
    assert!(results[0].ok, "{}", results[0].reason);
    assert_eq!(origin.bookmark_heads().unwrap(), vec![h1]);
    // The change was sealed at push and the reference attested.
    assert!(
        matches!(origin.authenticate_change(&h1).unwrap(), SignatureStatus::Valid { key, sealed: true, .. } if key == key_a)
    );
    assert_eq!(
        origin.verify_change(&h1).unwrap(),
        SignatureStatus::Unsigned
    );
    let (_, att) = origin.latest_ref_attest("main").unwrap().unwrap();
    assert!(matches!(att.attest.body, AttestBody::Ref { serial: 1, .. }));
    let again = a.push("origin", false).unwrap();
    assert!(again[0].ok && again[0].reason.contains("up to date"));
    let (_, att) = origin.latest_ref_attest("main").unwrap().unwrap();
    assert!(
        matches!(att.attest.body, AttestBody::Ref { serial: 1, .. }),
        "a no-op push does not attest again"
    );

    // B clones and sees the file and the seal.
    let b = Repo::clone(&origin_url, &root.join("b")).unwrap();
    assert_eq!(fs::read(root.join("b/f.txt")).unwrap(), b"a\n");
    assert_eq!(b.bookmark_heads().unwrap(), vec![h1]);
    assert!(matches!(
        b.authenticate_change(&h1).unwrap(),
        SignatureStatus::Valid { sealed: true, .. }
    ));

    // B (no identity) commits and pushes unsigned; the unverified origin accepts.
    write(&root.join("b"), "f.txt", b"a\nb\n");
    let h2 = b.commit("second", &[]).unwrap();
    assert!(b.push("origin", false).unwrap()[0].ok);
    assert_eq!(origin.bookmark_heads().unwrap(), vec![h2]);

    // A commits an independent change; push is refused until A pulls.
    write(&root.join("a"), "g.txt", b"g\n");
    let h3 = a.commit("third", &[]).unwrap();
    assert!(a.push("origin", false).is_err());
    let pr = a.pull("origin").unwrap();
    assert!(pr.changed && pr.checked_out);
    let mut want = vec![h2, h3];
    want.sort();
    assert_eq!(pr.heads, want);
    assert_eq!(fs::read(root.join("a/f.txt")).unwrap(), b"a\nb\n");
    assert_eq!(fs::read(root.join("a/g.txt")).unwrap(), b"g\n");
    let results = a.push("origin", false).unwrap();
    assert!(results[0].ok, "{}", results[0].reason);
    let mut origin_heads = origin.bookmark_heads().unwrap();
    origin_heads.sort();
    assert_eq!(origin_heads, want);
    let (_, att) = origin.latest_ref_attest("main").unwrap().unwrap();
    assert!(matches!(att.attest.body, AttestBody::Ref { serial: 2, .. }));

    // B pulls and ends up identical.
    let pr = b.pull("origin").unwrap();
    assert_eq!(pr.heads, want);
    assert_eq!(fs::read(root.join("b/g.txt")).unwrap(), b"g\n");
    assert!(!b.snapshot("status").unwrap().changed);

    // Concurrent edits of the same line: the union is a reified conflict.
    write(&root.join("a"), "f.txt", b"a\nA\n");
    a.commit("a-edit", &[]).unwrap();
    a.push("origin", false).unwrap();
    write(&root.join("b"), "f.txt", b"a\nB\n");
    b.commit("b-edit", &[]).unwrap();
    let pr = b.pull("origin").unwrap();
    assert!(pr.changed && pr.checked_out);
    let text = fs::read_to_string(root.join("b/f.txt")).unwrap();
    assert!(text.contains("<<<<<<< oxy conflict"), "{text}");
    write(&root.join("b"), "f.txt", b"a\nAB\n");
    let hr = b.commit("resolve", &[]).unwrap();
    assert_eq!(
        b.store().get_change(&hr).unwrap().kind,
        ChangeKind::Resolution
    );
    assert!(b.push("origin", false).unwrap()[0].ok);
    a.pull("origin").unwrap();
    assert_eq!(fs::read(root.join("a/f.txt")).unwrap(), b"a\nAB\n");
    // The resolution depends on the conflicting edits, but nothing depends
    // on "third" (it only added g.txt), so it stays a head beside it.
    let mut want = vec![hr, h3];
    want.sort();
    assert_eq!(a.bookmark_heads().unwrap(), want);
    assert!(!a.load_state(&want).unwrap().materialize().is_conflicted());
}

#[test]
fn receive_push_rejects_bad_updates() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let origin = Repo::init(&root.join("origin")).unwrap();
    let url = root.join("origin").to_string_lossy().to_string();
    let mut a = Repo::clone(&url, &root.join("a"))
        .unwrap()
        .with_home(root.join("home"));
    let (key, _) = a
        .create_identity("Ada", "a@b", IdentityScope::Repo)
        .unwrap();
    write(&root.join("a"), "f.txt", b"x\n");
    let h1 = a.commit("one", &[]).unwrap();
    assert!(a.push("origin", false).unwrap()[0].ok);
    let empty = origin.store().put_state(&StateObject::new(vec![])).unwrap();
    let s1 = origin
        .store()
        .put_state(&StateObject::new(vec![h1]))
        .unwrap();

    // Missing head.
    let ghost = origin
        .store()
        .put_state(&StateObject::new(vec![ObjectRef([9; 32])]))
        .unwrap();
    let r = origin
        .receive_push(
            Bundle::default(),
            vec![RefUpdate {
                name: "main".into(),
                old_state: s1,
                new_state: ghost,
                force: false,
                attestation: None,
            }],
            None,
            vec![],
        )
        .unwrap();
    assert!(
        !r[0].ok && r[0].reason.contains("missing"),
        "{}",
        r[0].reason
    );

    // Stale old_state.
    let r = origin
        .receive_push(
            Bundle::default(),
            vec![RefUpdate {
                name: "main".into(),
                old_state: empty,
                new_state: s1,
                force: false,
                attestation: None,
            }],
            None,
            vec![],
        )
        .unwrap();
    assert!(!r[0].ok && r[0].reason.contains("stale"), "{}", r[0].reason);

    // Non-fast-forward without force is refused; with force it passes.
    let r = origin
        .receive_push(
            Bundle::default(),
            vec![RefUpdate {
                name: "main".into(),
                old_state: s1,
                new_state: empty,
                force: false,
                attestation: None,
            }],
            None,
            vec![],
        )
        .unwrap();
    assert!(
        !r[0].ok && r[0].reason.contains("fast-forward"),
        "{}",
        r[0].reason
    );
    let r = origin
        .receive_push(
            Bundle::default(),
            vec![RefUpdate {
                name: "main".into(),
                old_state: s1,
                new_state: empty,
                force: true,
                attestation: None,
            }],
            None,
            vec![],
        )
        .unwrap();
    assert!(r[0].ok);
    assert_eq!(origin.bookmark_heads().unwrap(), vec![]);

    // Attestation with a stale serial is a rollback and is refused.
    let sa = a
        .sign_attest(&Attest {
            repo: a.id().unwrap(),
            hlc: Hlc::now(),
            body: AttestBody::Ref {
                name: "main".into(),
                old_state: empty,
                new_state: s1,
                serial: 1,
            },
        })
        .unwrap();
    let r = origin
        .receive_push(
            Bundle::default(),
            vec![RefUpdate {
                name: "main".into(),
                old_state: empty,
                new_state: s1,
                force: false,
                attestation: Some(sa.clone()),
            }],
            None,
            vec![],
        )
        .unwrap();
    assert!(
        !r[0].ok && r[0].reason.contains("serial"),
        "{}",
        r[0].reason
    );
    // An attestation for a different update is refused too.
    let sa2 = a
        .sign_attest(&Attest {
            repo: a.id().unwrap(),
            hlc: Hlc::now(),
            body: AttestBody::Ref {
                name: "main".into(),
                old_state: s1,
                new_state: empty,
                serial: 5,
            },
        })
        .unwrap();
    let r = origin
        .receive_push(
            Bundle::default(),
            vec![RefUpdate {
                name: "main".into(),
                old_state: empty,
                new_state: s1,
                force: false,
                attestation: Some(sa2),
            }],
            None,
            vec![],
        )
        .unwrap();
    assert!(
        !r[0].ok && r[0].reason.contains("describe"),
        "{}",
        r[0].reason
    );
    let _ = key;
}

#[test]
fn user_config_supplies_defaults_and_clones_sign() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let home = root.join("home");
    let origin = Repo::init(&root.join("origin")).unwrap();
    let url = root.join("origin").to_string_lossy().to_string();

    // Identity at user scope: the repository file stays free of author keys.
    let mut a = Repo::init(&root.join("a")).unwrap().with_home(&home);
    let (key, _) = a
        .create_identity("Ada", "[email protected]", IdentityScope::User)
        .unwrap();
    assert!(!a.config.repo_layer().contains_key("author.key"));
    assert_eq!(a.config.author_key, Some(key));
    assert!(home.join("config.toml").exists());
    a.set_user_config("core.sign", "change").unwrap();
    assert!(a.config.sign_changes);

    // Repository settings override user settings and are the only ones saved.
    a.config.set("core.sign", "seal").unwrap();
    a.save_config().unwrap();
    let again = Repo::open(&root.join("a")).unwrap().with_home(&home);
    assert!(!again.config.sign_changes);
    assert_eq!(again.config.author_key, Some(key));
    assert_eq!(
        read_config_file(&root.join("a/.oxy/config"))
            .unwrap()
            .get("core.sign")
            .map(String::as_str),
        Some("seal")
    );

    // A fresh clone made by this user signs with the user-level identity,
    // even though the clone's store has never seen the identity object.
    let b = Repo::clone(&url, &root.join("b")).unwrap().with_home(&home);
    assert!(b.config.sign_changes);
    write(&root.join("b"), "f.txt", b"f\n");
    let h = b.commit("signed from a clone", &[]).unwrap();
    assert!(
        matches!(b.verify_change(&h).unwrap(), SignatureStatus::Valid { key: k, .. } if k == key)
    );
    assert!(b.push("origin", false).unwrap()[0].ok);
    assert!(matches!(
        origin.verify_change(&h).unwrap(),
        SignatureStatus::Valid { .. }
    ));
}

#[test]
fn format1_repositories_are_migrated_on_open() {
    hermetic();
    use crate::oplog::{Format1Op, Format1View};
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap();
    write(root, "a.txt", b"a\n");
    let h1 = repo.commit("one", &[]).unwrap();
    let (wc_hash, _) = repo.working_copy().unwrap();
    // Rewrite the op log the way format 1 stored it: two ops, head lists.
    let mut v1 = Format1View::default();
    v1.bookmarks.insert("main".into(), vec![]);
    v1.workspaces.insert(repo.workspace(), wc_hash);
    let init = Format1Op {
        parents: vec![],
        hlc: Hlc::default(),
        command: "oxy init".into(),
        view: v1.clone(),
    };
    let init_ref = repo.store().put(ObjectType::Op, &init.encode()).unwrap();
    v1.bookmarks.insert("main".into(), vec![h1]);
    let commit = Format1Op {
        parents: vec![init_ref],
        hlc: Hlc::default(),
        command: "oxy commit".into(),
        view: v1,
    };
    let commit_ref = repo.store().put(ObjectType::Op, &commit.encode()).unwrap();
    write_atomic(&root.join(".oxy/ops/head"), commit_ref.to_hex().as_bytes()).unwrap();
    write_atomic(&root.join(".oxy/format"), FORMAT1_LINE.as_bytes()).unwrap();
    drop(repo);

    let repo = Repo::open(root).unwrap();
    assert_eq!(
        fs::read_to_string(root.join(".oxy/format")).unwrap(),
        FORMAT_LINE
    );
    assert_eq!(repo.bookmark_heads().unwrap(), vec![h1]);
    let ops = repo.op_log().unwrap();
    assert_eq!(
        ops.iter()
            .map(|(_, o)| o.command.as_str())
            .collect::<Vec<_>>(),
        ["oxy commit", "oxy init"]
    );
    assert_eq!(repo.heads_of(&ops[1].1.view, "main").unwrap(), vec![]);
    assert!(!repo.snapshot("status").unwrap().changed);
    // Reopening again is a no-op.
    assert_eq!(Repo::open(root).unwrap().op_log().unwrap().len(), 2);
}

#[test]
fn undo_skips_snapshot_operations() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap();
    write(root, "a.txt", b"a\n");
    let h1 = repo.commit("a", &[]).unwrap();
    // A later command snapshots new edits on top of the commit.
    write(root, "b.txt", b"b\n");
    let s = repo.snapshot("oxy status").unwrap();
    assert!(s.changed);
    assert!(repo.head_op().unwrap().1.is_snapshot());
    assert_eq!(repo.last_command().unwrap().command, "oxy commit -m \"a\"");
    // Undo must undo the commit, not the snapshot.
    repo.undo().unwrap();
    assert_eq!(repo.bookmark_heads().unwrap(), vec![]);
    let s = repo.snapshot("oxy status").unwrap();
    let paths: Vec<_> = s.statuses.iter().map(|p| p.path.as_str()).collect();
    assert_eq!(
        paths,
        ["a.txt", "b.txt"],
        "both files are back in the working copy"
    );
    assert!(repo.store().get_change(&h1).unwrap().deps.is_empty());
    // Only snapshots remain above `init`, so there is nothing left to undo.
    assert_eq!(repo.last_command().unwrap().command, "oxy init");
    assert!(repo.undo().is_err());
}

#[test]
fn independent_changes_commute_and_make_multiple_heads() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap();
    write(root, "a.txt", b"a\n");
    let h1 = repo.commit("a", &[]).unwrap();
    write(root, "b.txt", b"b\n");
    let h2 = repo.commit("b", &[]).unwrap();
    let c2 = repo.store().get_change(&h2).unwrap();
    assert!(c2.deps.is_empty(), "b.txt touches nothing from h1");
    let mut heads = repo.bookmark_heads().unwrap();
    heads.sort();
    let mut want = vec![h1, h2];
    want.sort();
    assert_eq!(heads, want);
    // Editing a.txt depends on h1 only.
    write(root, "a.txt", b"a\na2\n");
    let h3 = repo.commit("a2", &[]).unwrap();
    assert_eq!(repo.store().get_change(&h3).unwrap().deps, vec![h1]);
    let heads: BTreeSet<_> = repo.bookmark_heads().unwrap().into_iter().collect();
    assert_eq!(heads, [h2, h3].into_iter().collect());
    // Explicit dependency.
    write(root, "c.txt", b"c\n");
    let h4 = repo.commit("c", &[h2]).unwrap();
    assert_eq!(repo.store().get_change(&h4).unwrap().deps, vec![h2]);
}

#[test]
fn mode_change_and_text_binary_switch() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap();
    write(root, "run.sh", b"#!/bin/sh\n");
    repo.commit("add script", &[]).unwrap();
    #[cfg(unix)]
    {
        use std::os::unix::fs::PermissionsExt;
        fs::set_permissions(root.join("run.sh"), fs::Permissions::from_mode(0o755)).unwrap();
        let s = repo.snapshot("status").unwrap();
        assert_eq!(
            statuses(&s),
            vec![("run.sh".into(), ChangeStatus::ModeChanged)]
        );
        let h = repo.commit("exec", &[]).unwrap();
        let snap = repo.load_state(&[h]).unwrap().materialize();
        assert!(snap.files["run.sh"].mode.exec);
    }
    // Text → binary → text.
    write(root, "run.sh", b"\0binary");
    let h = repo.commit("binary", &[]).unwrap();
    let snap = repo.load_state(&[h]).unwrap().materialize();
    assert!(snap.files["run.sh"].mode.opaque);
    write(root, "run.sh", b"text again\n");
    let h = repo.commit("text", &[]).unwrap();
    let snap = repo.load_state(&[h]).unwrap().materialize();
    assert!(!snap.files["run.sh"].mode.opaque);
    assert!(
        matches!(&snap.files["run.sh"].content, FileContent::Text { bytes, .. } if bytes == b"text again\n")
    );
    assert!(!snap.is_conflicted());
}

#[test]
fn trust_policy_governs_pushes_and_fetches() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let origin = Repo::init(&root.join("origin")).unwrap();
    let url = root.join("origin").to_string_lossy().to_string();

    // A is the root. Before the policy, an unsigned push from B is fine.
    let mut a = Repo::clone(&url, &root.join("a"))
        .unwrap()
        .with_home(root.join("home-a"));
    let (key_a, _) = a
        .create_identity("Ada", "[email protected]", IdentityScope::User)
        .unwrap();
    let mut b = Repo::clone(&url, &root.join("b"))
        .unwrap()
        .with_home(root.join("home-b"));
    write(&root.join("b"), "b.txt", b"b\n");
    b.commit("unsigned before policy", &[]).unwrap();
    assert!(b.push("origin", false).unwrap()[0].ok);

    // A creates the policy and pushes it; origin now enforces it.
    write(&root.join("a"), "a.txt", b"a\n");
    a.commit("a", &[]).unwrap();
    let sp = a.policy_init().unwrap();
    assert_eq!(sp.policy.serial, 1);
    a.pull("origin").unwrap();
    let results = a.push("origin", false).unwrap();
    assert!(results.iter().all(|r| r.ok), "{results:?}");
    assert_eq!(origin.current_policy().unwrap().unwrap().1.policy.serial, 1);

    // B pulls the policy. Without an identity B cannot push at all.
    b.pull("origin").unwrap();
    assert!(
        b.current_policy().unwrap().is_some(),
        "the policy arrived with the fetch"
    );
    assert!(b.push("origin", false).is_err());
    // With an identity the policy does not list, the push is rejected by origin.
    let (key_b, id_b) = b
        .create_identity("Bob", "[email protected]", IdentityScope::User)
        .unwrap();
    write(&root.join("b"), "b.txt", b"b2\n");
    let h_b2 = b.commit("b2 as Bob", &[]).unwrap();
    assert_eq!(b.store().get_change(&h_b2).unwrap().author, key_b);
    let r = b.push("origin", false).unwrap();
    assert!(
        !r[0].ok && r[0].reason.contains("may not update"),
        "{:?}",
        r
    );

    // A grants B (identity handed over as a file) and publishes the policy.
    let sp = a.policy_grant(id_b.clone(), None).unwrap();
    assert_eq!(sp.policy.serial, 2);
    let r = a.push("origin", false).unwrap();
    assert!(r.iter().any(|x| x.name == "policy" && x.ok), "{r:?}");
    // B must fetch the new policy before pushing.
    assert!(b
        .push("origin", false)
        .unwrap_or_else(|e| vec![RefResult {
            name: "main".into(),
            ok: false,
            reason: e.to_string()
        }])
        .iter()
        .all(|x| !x.ok));
    b.pull("origin").unwrap();
    assert_eq!(b.current_policy().unwrap().unwrap().1.policy.serial, 2);
    let r = b.push("origin", false).unwrap();
    assert!(r[0].ok, "{:?}", r);
    // Origin verified B's change under the policy.
    let heads = origin.bookmark_heads().unwrap();
    for h in &heads {
        let c = origin.store().get_change(h).unwrap();
        if c.author == key_b {
            origin
                .change_allowed(
                    h,
                    &origin.current_policy().unwrap().unwrap().1.policy,
                    "main",
                )
                .unwrap();
        }
    }

    // A policy signed by a non-root (B) is refused, as is a replayed serial.
    let mut forged = b.current_policy().unwrap().unwrap().1.policy.clone();
    forged.serial = 3;
    forged.roots = vec![key_b];
    let fh = forged.hash();
    let (_, sk_b) = b.secret_key().unwrap().unwrap();
    let forged = SignedPolicy {
        policy: forged,
        sigs: vec![sk_b.sign(Domain::Policy, &key_b, &fh)],
    };
    let r = origin
        .receive_push(Bundle::default(), vec![], Some(forged), vec![])
        .unwrap();
    assert!(!r[0].ok && r[0].reason.contains("root"), "{:?}", r);
    let stale = a.current_policy().unwrap().unwrap().1;
    let mut old = stale.clone();
    old.policy.serial = 1;
    let r = origin
        .receive_push(Bundle::default(), vec![], Some(old), vec![])
        .unwrap();
    assert!(!r[0].ok && r[0].reason.contains("serial"), "{:?}", r);

    // A revokes B; after B pulls the policy, B's pushes are refused again.
    a.pull("origin").unwrap();
    a.policy_revoke(&key_b).unwrap();
    let r = a.push("origin", false).unwrap();
    assert!(r.iter().any(|x| x.name == "policy" && x.ok), "{r:?}");
    b.pull("origin").unwrap();
    write(&root.join("b"), "b.txt", b"b3\n");
    b.commit("b3", &[]).unwrap();
    let r = b.push("origin", false).unwrap();
    assert!(!r[0].ok, "{:?}", r);

    // A clone by a third party receives and verifies everything.
    let c = Repo::clone(&url, &root.join("c"))
        .unwrap()
        .with_home(root.join("home-c"));
    assert_eq!(c.current_policy().unwrap().unwrap().1.policy.serial, 3);
    assert!(c
        .current_policy()
        .unwrap()
        .unwrap()
        .1
        .policy
        .roots
        .contains(&key_a));
    assert!(!c.snapshot("status").unwrap().changed);
}

#[test]
fn gc_packs_objects_and_history_still_works() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let mut repo = Repo::init(root).unwrap().with_home(root.join("home"));
    repo.create_identity("Ada", "a@b", IdentityScope::User)
        .unwrap();
    repo.set_user_config("core.sign", "change").unwrap();
    write(root, "a.txt", b"one\n");
    let h1 = repo.commit("one", &[]).unwrap();
    write(root, "a.txt", b"two\n");
    write(root, "big.bin", &vec![0u8; 100_000]);
    let h2 = repo.commit("two", &[]).unwrap();
    // Several snapshots leave superseded working-copy versions behind.
    for i in 0..5 {
        write(root, "a.txt", format!("two\n{i}\n").as_bytes());
        repo.snapshot("status").unwrap();
    }
    write(root, "a.txt", b"two\n");
    repo.snapshot("status").unwrap();
    let before = repo.store().list().unwrap();
    assert!(repo.store().loose_count().unwrap() > 0);

    // With the default retention every operation's view is a root: nothing prunes.
    let r = repo.gc(true).unwrap();
    assert_eq!(r.packed.objects, before.len());
    assert_eq!(r.pruned.objects, 0);
    assert_eq!(repo.store().loose_count().unwrap(), 0);
    assert_eq!(repo.store().list().unwrap(), before);

    // With zero retention only the current view is a root: superseded
    // working copies go, everything reachable stays.
    repo.config.set("core.op-retention", "0").unwrap();
    repo.save_config().unwrap();
    let repo = Repo::open(root).unwrap().with_home(root.join("home"));
    let r = repo.gc(true).unwrap();
    assert!(r.pruned.objects >= 5, "{r:?}");
    let after = repo.store().list().unwrap();
    assert!(after.len() < before.len());
    assert!(after.contains(&h1) && after.contains(&h2));
    for (_, op) in repo.op_log().unwrap() {
        assert!(!op.command.is_empty(), "operation objects are all kept");
    }
    // Everything still works from the pruned, packed store.
    assert_eq!(repo.bookmark_heads().unwrap(), vec![h2]);
    assert!(matches!(
        repo.verify_change(&h2).unwrap(),
        SignatureStatus::Valid { .. }
    ));
    assert_eq!(repo.log().unwrap().len(), 3);
    repo.checkout(&[h1], false, "checkout").unwrap();
    assert_eq!(fs::read(root.join("a.txt")).unwrap(), b"one\n");
    repo.checkout(&[h2], false, "checkout").unwrap();
    assert_eq!(fs::read(root.join("big.bin")).unwrap().len(), 100_000);
    assert!(!repo.snapshot("status").unwrap().changed);
    // Grace period defers pruning of young garbage.
    write(root, "a.txt", b"three\n");
    repo.commit("three", &[]).unwrap();
    let r = repo.gc(false).unwrap();
    assert_eq!(r.pruned.objects, 0);
    assert!(r.pruned.deferred > 0);
    let r = repo.gc(true).unwrap();
    assert!(r.pruned.objects > 0);
    assert_eq!(repo.log().unwrap().len(), 4);
}

#[test]
fn describe_amend_abandon_heads() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let mut repo = Repo::init(root).unwrap().with_home(root.join("home"));
    repo.create_identity("Ada", "a@b", IdentityScope::User)
        .unwrap();
    repo.set_user_config("core.sign", "change").unwrap();
    write(root, "a.txt", b"one\n");
    let h1 = repo.commit("first", &[]).unwrap();
    write(root, "a.txt", b"one\ntwo\n");
    let h2 = repo.commit("secnod", &[]).unwrap();
    let id2 = repo.store().get_change(&h2).unwrap().change_id;

    // describe: same ChangeId, new hash, bookmark and working copy follow.
    let h2b = repo.describe(&h2, "second").unwrap();
    assert_ne!(h2b, h2);
    let c = repo.store().get_change(&h2b).unwrap();
    assert_eq!(
        (c.change_id, c.message.as_str(), c.deps.clone()),
        (id2, "second", vec![h1])
    );
    assert_eq!(repo.bookmark_heads().unwrap(), vec![h2b]);
    assert!(matches!(
        repo.verify_change(&h2b).unwrap(),
        SignatureStatus::Valid { .. }
    ));
    let s = repo.snapshot("status").unwrap();
    assert!(s.statuses.is_empty(), "{:?}", s.statuses);
    assert_eq!(
        repo.resolve_change(&id2.short(8)).unwrap(),
        h2b,
        "the old object is no longer reachable from the log"
    );
    // Describing a non-head rewrites its dependents (h2b → h2c') and the working copy.
    let h1b = repo.describe(&h1, "first, described").unwrap();
    assert_ne!(h1b, h1);
    let heads = repo.bookmark_heads().unwrap();
    assert_eq!(heads.len(), 1);
    let top = repo.store().get_change(&heads[0]).unwrap();
    assert_eq!((top.change_id, top.deps.clone()), (id2, vec![h1b]));
    assert!(
        matches!(
            repo.verify_change(&heads[0]).unwrap(),
            SignatureStatus::Valid { .. }
        ),
        "rewritten own change is re-signed"
    );
    let (_, wc) = repo.working_copy().unwrap();
    assert_eq!(
        wc.deps,
        vec![heads[0]],
        "the working copy follows the rewrite"
    );
    assert!(!repo.snapshot("status").unwrap().changed);
    let snap = repo.load_state(&heads).unwrap().materialize();
    assert!(
        matches!(&snap.files["a.txt"].content, FileContent::Text { bytes, .. } if bytes == b"one\ntwo\n")
    );

    // amend: fold an edit into the head; the result is one change from h1.
    write(root, "a.txt", b"one\ntwo\nthree\n");
    write(root, "b.txt", b"b\n");
    let h2c = repo.amend(None).unwrap();
    let c = repo.store().get_change(&h2c).unwrap();
    assert_eq!(c.change_id, id2);
    assert_eq!(c.message, "second");
    assert_eq!(repo.bookmark_heads().unwrap(), vec![h2c]);
    assert_eq!(
        repo.log().unwrap().len(),
        3,
        "working copy, amended head, first"
    );
    let snap = repo.load_state(&[h2c]).unwrap().materialize();
    assert!(
        matches!(&snap.files["a.txt"].content, FileContent::Text { bytes, .. } if bytes == b"one\ntwo\nthree\n")
    );
    assert!(snap.files.contains_key("b.txt"));
    assert!(!repo.snapshot("status").unwrap().changed);
    assert!(
        repo.amend(None).is_err(),
        "clean working copy and no message"
    );
    let h2d = repo.amend(Some("second, amended")).unwrap();
    assert_eq!(
        repo.store().get_change(&h2d).unwrap().message,
        "second, amended"
    );

    // abandon: the head goes, its content stays as uncommitted work.
    repo.abandon(&h2d).unwrap();
    assert_eq!(
        repo.bookmark_heads().unwrap(),
        vec![h1b],
        "the described first change is the head again"
    );
    let s = repo.snapshot("status").unwrap();
    let paths: Vec<_> = s
        .statuses
        .iter()
        .map(|p| (p.path.as_str(), p.status))
        .collect();
    assert_eq!(
        paths,
        vec![
            ("a.txt", ChangeStatus::Modified),
            ("b.txt", ChangeStatus::Added)
        ]
    );
    assert_eq!(fs::read(root.join("a.txt")).unwrap(), b"one\ntwo\nthree\n");
    let h3 = repo.commit("recommitted", &[]).unwrap();
    assert_eq!(repo.bookmark_heads().unwrap(), vec![h3]);
    // undo brings the abandoned head back.
    repo.undo().unwrap();
    repo.undo().unwrap();
    assert_eq!(repo.bookmark_heads().unwrap(), vec![h2d]);

    // Abandoning a non-head whose dependent references its atoms reifies
    // the references (here: a.txt vanishes with it, so the dependent's edit
    // of a.txt is dropped with a note) instead of refusing; undo restores it.
    let base = repo.bookmark_heads().unwrap()[0];
    let base_change = repo.store().get_change(&base).unwrap();
    let h1_now = base_change.deps[0];
    let notes = repo.abandon(&h1_now).unwrap();
    assert!(
        !notes.is_empty(),
        "the dependent's edit of a.txt was reified"
    );
    let heads = repo.bookmark_heads().unwrap();
    let after = repo.load_state(&heads).unwrap().materialize();
    assert!(
        !after.files.contains_key("a.txt") && after.files.contains_key("b.txt"),
        "{:?}",
        after.files.keys()
    );
    repo.undo().unwrap();
    assert_eq!(repo.bookmark_heads().unwrap(), vec![base]);
    write(root, "c.txt", b"c\n");
    let hc = repo.commit("c", &[]).unwrap();
    write(root, "d.txt", b"d\n");
    let hd = repo.commit("d", &[hc]).unwrap();
    assert_eq!(repo.store().get_change(&hd).unwrap().deps, vec![hc]);
    repo.abandon(&hc).unwrap();
    let heads: BTreeSet<_> = repo.bookmark_heads().unwrap().into_iter().collect();
    assert!(!heads.contains(&hc));
    let d_now = heads
        .iter()
        .find(|h| repo.store().get_change(h).unwrap().message == "d")
        .copied()
        .unwrap();
    assert!(
        repo.store().get_change(&d_now).unwrap().deps.is_empty(),
        "d inherited c's (empty) dependencies"
    );
    let s = repo.snapshot("status").unwrap();
    assert_eq!(
        s.statuses
            .iter()
            .map(|p| p.path.as_str())
            .collect::<Vec<_>>(),
        vec!["c.txt"],
        "c's content is now uncommitted work"
    );
}

#[test]
fn git_export_mirrors_history() {
    hermetic();
    if std::process::Command::new("git")
        .arg("--version")
        .output()
        .is_err()
    {
        eprintln!("git not installed; skipping");
        return;
    }
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let mut repo = Repo::init(&root.join("r"))
        .unwrap()
        .with_home(root.join("home"));
    repo.create_identity("Ada Lovelace", "[email protected]", IdentityScope::User)
        .unwrap();
    let r = root.join("r");
    write(&r, "README.md", b"hello\n");
    write(&r, "src/main.rs", b"fn main() {}\n");
    let h1 = repo.commit("first", &[]).unwrap();
    write(&r, "src/main.rs", b"fn main() { run(); }\n");
    write(&r, "logo.png", b"\x89PNG\0\0");
    let h2 = repo.commit("second", &[]).unwrap();

    let git_dir = root.join("mirror.git");
    let rep = repo.git_export(&git_dir).unwrap();
    assert_eq!((rep.exported, rep.skipped, rep.heads), (2, 0, 1));
    let git = |args: &[&str]| -> String {
        let out = std::process::Command::new("git")
            .arg("-C")
            .arg(&git_dir)
            .args(args)
            .output()
            .unwrap();
        assert!(
            out.status.success(),
            "{}",
            String::from_utf8_lossy(&out.stderr)
        );
        String::from_utf8_lossy(&out.stdout).trim().to_string()
    };
    assert_eq!(git(&["log", "--format=%s", "main"]), "second\nfirst");
    assert_eq!(git(&["show", "main:src/main.rs"]), "fn main() { run(); }");
    assert_eq!(git(&["show", "main:README.md"]), "hello");
    let body = git(&["log", "-1", "--format=%B", "main"]);
    assert!(
        body.contains(&format!("Oxy-Hash: {}", h2.to_hex())),
        "{body}"
    );
    assert!(body.contains("Change-Id: "), "{body}");
    assert_eq!(
        git(&["log", "-1", "--format=%an <%ae>", "main"]),
        "Ada Lovelace <[email protected]>"
    );
    assert_eq!(
        git(&["ls-tree", "--name-only", "main"]),
        "README.md\nlogo.png\nsrc"
    );

    // Re-export is incremental.
    let rep = repo.git_export(&git_dir).unwrap();
    assert_eq!((rep.exported, rep.skipped), (0, 2));

    // An independent change makes two heads; the next state is one more
    // commit on the linear branch whose tree is the union.
    repo.checkout(&[h1], false, "checkout").unwrap();
    write(&r, "other.txt", b"o\n");
    let h3 = repo.commit("third", &[]).unwrap();
    let rep = repo.git_export(&git_dir).unwrap();
    assert_eq!((rep.exported, rep.heads), (1, 2));
    assert_eq!(git(&["log", "--format=%s", "main"]), "third\nsecond\nfirst");
    let parents = git(&["rev-list", "--parents", "-1", "main"]);
    assert_eq!(parents.split(' ').count(), 2, "one parent: {parents}");
    assert_eq!(git(&["show", "main:other.txt"]), "o");
    assert_eq!(git(&["show", "main:src/main.rs"]), "fn main() { run(); }");
    assert_eq!(
        git(&["ls-tree", "--name-only", "main"]),
        "README.md\nlogo.png\nother.txt\nsrc"
    );
    let body = git(&["log", "-1", "--format=%B", "main"]);
    assert!(
        body.contains(&format!("Oxy-Hash: {}", h3.to_hex())) && body.contains("Oxy-State: "),
        "{body}"
    );
    // A rewrite is a new state whose one new change is the rewritten one.
    repo.describe(&h3, "third, described").unwrap();
    let rep = repo.git_export(&git_dir).unwrap();
    assert_eq!(rep.exported, 1);
    assert_eq!(
        git(&["log", "-1", "--format=%s", "main"]),
        "third, described"
    );
    assert_eq!(git(&["log", "--format=%s", "main"]).lines().count(), 4);
    let _ = h2;
}

#[test]
fn git_import_reproduces_trees() {
    hermetic();
    if std::process::Command::new("git")
        .arg("--version")
        .output()
        .is_err()
    {
        eprintln!("git not installed; skipping");
        return;
    }
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let g = root.join("src.git");
    fs::create_dir_all(&g).unwrap();
    let git = |args: &[&str]| -> String {
        let out = std::process::Command::new("git")
            .arg("-C")
            .arg(&g)
            .args([
                "-c",
                "user.name=Grace",
                "-c",
                "[email protected]",
                "-c",
                "commit.gpgsign=false",
            ])
            .args(args)
            .output()
            .unwrap();
        assert!(
            out.status.success(),
            "git {args:?}: {}",
            String::from_utf8_lossy(&out.stderr)
        );
        String::from_utf8_lossy(&out.stdout).trim().to_string()
    };
    git(&["init", "-q", "-b", "main"]);
    write(&g, "README.md", b"# Hi\n");
    write(&g, "src/lib.rs", b"pub fn a() {}\n");
    git(&["add", "."]);
    git(&["commit", "-q", "-m", "initial"]);
    write(&g, "src/lib.rs", b"pub fn a() {}\npub fn b() {}\n");
    write(&g, "run.sh", b"#!/bin/sh\n");
    #[cfg(unix)]
    {
        use std::os::unix::fs::PermissionsExt;
        fs::set_permissions(g.join("run.sh"), fs::Permissions::from_mode(0o755)).unwrap();
    }
    write(&g, "logo.png", b"\x89PNG\0\0\x01");
    git(&["add", "."]);
    git(&[
        "commit",
        "-q",
        "-m",
        "second\n\nChange-Id: 0123456789abcdef0123456789abcdef",
    ]);
    // A branch that edits README, merged back with a conflict-free merge.
    git(&["checkout", "-q", "-b", "topic", "HEAD~1"]);
    write(&g, "README.md", b"# Hi\n\nMore.\n");
    git(&["commit", "-q", "-am", "readme"]);
    git(&["checkout", "-q", "main"]);
    git(&["merge", "-q", "--no-ff", "-m", "merge topic", "topic"]);
    // A branch from the initial commit inserting at the same place as
    // "second": concurrent in Oxygen too, so the merge commit is a resolution.
    let initial = git(&["rev-list", "--max-parents=0", "HEAD"]);
    git(&["checkout", "-q", "-b", "clash", &initial]);
    write(&g, "src/lib.rs", b"pub fn a() {}\npub fn c() {}\n");
    git(&["commit", "-q", "-am", "clash"]);
    git(&["checkout", "-q", "main"]);
    let _ = std::process::Command::new("git")
        .arg("-C")
        .arg(&g)
        .args(["merge", "-q", "clash"])
        .output();
    write(
        &g,
        "src/lib.rs",
        b"pub fn a() {}\npub fn b() {}\npub fn c() {}\n",
    );
    git(&["add", "."]);
    git(&["commit", "-q", "-m", "resolve clash"]);
    git(&["rm", "-q", "logo.png"]);
    git(&["commit", "-q", "-m", "drop logo"]);
    // A rename with a small edit is imported as a move of the same node.
    git(&["mv", "src/lib.rs", "src/lib2.rs"]);
    write(
        &g,
        "src/lib2.rs",
        b"pub fn a() {}\npub fn b() {}\npub fn c() {}\npub fn d() {}\n",
    );
    git(&["add", "."]);
    git(&["commit", "-q", "-m", "rename lib"]);
    let expected_count: usize = git(&["rev-list", "--count", "main"]).parse().unwrap();

    let dest = root.join("oxy");
    let repo = Repo::init(&dest).unwrap().with_home(root.join("home"));
    let rep = repo.import_git(&g, "main").unwrap();
    assert_eq!(rep.commits, expected_count);
    assert_eq!(rep.merges, 2);
    // The working copy equals the Git tree at main.
    assert_eq!(
        fs::read(dest.join("src/lib2.rs")).unwrap(),
        b"pub fn a() {}\npub fn b() {}\npub fn c() {}\npub fn d() {}\n"
    );
    assert!(!dest.join("src/lib.rs").exists());
    assert_eq!(
        fs::read(dest.join("README.md")).unwrap(),
        b"# Hi\n\nMore.\n"
    );
    assert!(!dest.join("logo.png").exists());
    #[cfg(unix)]
    {
        use std::os::unix::fs::PermissionsExt;
        assert!(
            fs::metadata(dest.join("run.sh"))
                .unwrap()
                .permissions()
                .mode()
                & 0o111
                != 0
        );
    }
    assert!(
        !repo.snapshot("status").unwrap().changed,
        "clean after import"
    );
    let heads = repo.bookmark_heads().unwrap();
    let st = repo.load_state(&heads).unwrap();
    assert!(!st.materialize().is_conflicted());
    assert_eq!(st.len(), expected_count);
    let tip = repo
        .log()
        .unwrap()
        .into_iter()
        .find(|e| e.change.message.starts_with("rename lib"))
        .unwrap();
    let c = repo.store().get_change(&tip.hash).unwrap();
    assert!(
        c.tree_ops
            .iter()
            .any(|op| matches!(op, TreeOp::Move { name, .. } if name == "lib2.rs")),
        "{:?}",
        c.tree_ops
    );
    assert!(!c
        .tree_ops
        .iter()
        .any(|op| matches!(op, TreeOp::AddNode { .. })));
    // Messages carry Git trailers; the Change-Id trailer was honoured.
    let log = repo.log().unwrap();
    let second = log
        .iter()
        .find(|e| e.change.message.starts_with("second"))
        .unwrap();
    assert_eq!(
        second.change.change_id,
        ChangeId::from_hex("0123456789abcdef0123456789abcdef").unwrap()
    );
    assert!(second
        .change
        .message
        .contains("Git-Author: Grace <[email protected]>"));
    let resolve = log
        .iter()
        .find(|e| e.change.message.starts_with("resolve clash"))
        .unwrap();
    assert_eq!(
        resolve.change.kind,
        ChangeKind::Resolution,
        "a conflicting Git merge becomes a resolution"
    );
    // Re-importing into another fresh repository gives the same ChangeIds.
    let repo2 = Repo::init(&root.join("oxy2"))
        .unwrap()
        .with_home(root.join("home"));
    repo2.import_git(&g, "main").unwrap();
    let ids: BTreeSet<ChangeId> = repo
        .log()
        .unwrap()
        .iter()
        .filter(|e| !e.is_working_copy)
        .map(|e| e.change.change_id)
        .collect();
    let ids2: BTreeSet<ChangeId> = repo2
        .log()
        .unwrap()
        .iter()
        .filter(|e| !e.is_working_copy)
        .map(|e| e.change.change_id)
        .collect();
    assert_eq!(ids, ids2);
    // Round trip back out to Git reproduces the tip tree.
    let mirror = root.join("mirror.git");
    repo.git_export(&mirror).unwrap();
    let out = std::process::Command::new("git")
        .arg("-C")
        .arg(&mirror)
        .args(["show", "main:src/lib2.rs"])
        .output()
        .unwrap();
    assert_eq!(
        String::from_utf8_lossy(&out.stdout),
        "pub fn a() {}\npub fn b() {}\npub fn c() {}\npub fn d() {}\n"
    );
    let out = std::process::Command::new("git")
        .arg("-C")
        .arg(&mirror)
        .args(["show", "main:src/lib.rs"])
        .output()
        .unwrap();
    assert!(
        !out.status.success(),
        "the old path is gone from the export"
    );
}

#[test]
fn checkpoints_accelerate_loading_and_stay_correct() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let mut repo = Repo::init(root).unwrap().with_home(root.join("home"));
    repo.config.set("core.checkpoint-interval", "5").unwrap();
    repo.save_config().unwrap();
    let repo = Repo::open(root).unwrap().with_home(root.join("home"));
    let mut hashes = Vec::new();
    for i in 0..12 {
        write(
            root,
            "a.txt",
            format!(
                "{}\n",
                (0..=i)
                    .map(|k| k.to_string())
                    .collect::<Vec<_>>()
                    .join("\n")
            )
            .as_bytes(),
        );
        write(root, &format!("f{i}.txt"), b"x\n");
        hashes.push(repo.commit(&format!("c{i}"), &[]).unwrap());
    }
    let (_, cp) = repo
        .latest_checkpoint("main")
        .unwrap()
        .expect("automatic checkpoint");
    assert!(cp.count >= 5 && cp.count <= 12, "{}", cp.count);
    // Loading through the checkpoint equals loading everything.
    let heads = repo.bookmark_heads().unwrap();
    let fast = repo.load_state(&heads).unwrap();
    let full = repo.load_state_full(&heads).unwrap();
    assert_eq!(fast.len(), full.len());
    assert_eq!(fast.heads(), full.heads());
    let (a, b) = (fast.materialize(), full.materialize());
    assert_eq!(
        a.files.keys().collect::<Vec<_>>(),
        b.files.keys().collect::<Vec<_>>()
    );
    for (p, f) in &a.files {
        assert_eq!(f.content, b.files[p].content, "{p}");
    }
    assert!(repo.load_state_checkpointed(&heads).unwrap().is_some());
    // A head set that does not contain the checkpoint's heads falls back.
    assert!(repo
        .load_state_checkpointed(&[hashes[0]])
        .unwrap()
        .is_none());
    assert_eq!(repo.load_state(&[hashes[0]]).unwrap().len(), 1);
    // Everything else keeps working on top of the checkpoint.
    assert!(!repo.snapshot("status").unwrap().changed);
    let h = repo.describe(&hashes[3], "c3 described").unwrap();
    assert_eq!(repo.store().get_change(&h).unwrap().message, "c3 described");
    let (r, n, bytes) = repo.checkpoint().unwrap();
    assert!(n >= 12 && bytes > 0);
    assert_eq!(repo.latest_checkpoint("main").unwrap().unwrap().0, r);
    write(root, "a.txt", b"after\n");
    let h_after = repo.commit("after", &[]).unwrap();
    let st = repo.load_state(&repo.bookmark_heads().unwrap()).unwrap();
    assert!(st.contains(&h_after));
    assert!(
        matches!(&st.materialize().files["a.txt"].content, FileContent::Text { bytes, .. } if bytes == b"after\n")
    );
    assert_eq!(repo.log().unwrap().len(), 14);
    // Checkpoints survive gc.
    repo.gc(true).unwrap();
    assert!(repo.latest_checkpoint("main").unwrap().is_some());
    assert!(repo
        .load_state_checkpointed(&repo.bookmark_heads().unwrap())
        .unwrap()
        .is_some());
}

#[test]
fn quick_status_for_prompts() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let origin = Repo::init(&root.join("origin")).unwrap();
    let url = root.join("origin").to_string_lossy().to_string();
    let a = Repo::clone(&url, &root.join("a"))
        .unwrap()
        .with_home(root.join("home"));
    let ops_before = a.op_log().unwrap().len();
    let info = a.quick_status().unwrap();
    assert_eq!(
        (
            info.bookmark.as_str(),
            info.heads,
            info.dirty,
            info.conflicted,
            info.ahead,
            info.behind
        ),
        ("main", 0, false, false, Some(0), Some(0))
    );
    write(&root.join("a"), "f.txt", b"f\n");
    assert!(a.quick_status().unwrap().dirty, "a new file is dirty");
    assert_eq!(
        a.op_log().unwrap().len(),
        ops_before,
        "quick_status records nothing"
    );
    // A snapshotted but uncommitted change is still dirty.
    a.snapshot("status").unwrap();
    assert!(a.quick_status().unwrap().dirty);
    a.commit("f", &[]).unwrap();
    let info = a.quick_status().unwrap();
    assert!(!info.dirty, "clean right after a commit");
    assert_eq!((info.ahead, info.behind), (Some(1), Some(0)));
    assert_eq!(
        info.format("%b %c%d%x%A%D"),
        format!("main {}+1", info.change_id)
    );
    assert_eq!(info.format("[%h heads] %a/%B %%"), "[1 heads] 1/0 %");
    // Touching a file without changing it is not dirty; changing content of
    // the same size is.
    let p = root.join("a/f.txt");
    let content = fs::read(&p).unwrap();
    fs::write(&p, &content).unwrap();
    assert!(!a.quick_status().unwrap().dirty);
    fs::write(&p, b"g\n").unwrap();
    assert!(a.quick_status().unwrap().dirty);
    fs::write(&p, b"f\n").unwrap();
    // Push, then a second clone commits and pushes: we are behind.
    assert!(a.push("origin", false).unwrap()[0].ok);
    assert_eq!(a.quick_status().unwrap().ahead, Some(0));
    let b = Repo::clone(&url, &root.join("b"))
        .unwrap()
        .with_home(root.join("home-b"));
    write(&root.join("b"), "g.txt", b"g\n");
    b.commit("g", &[]).unwrap();
    b.push("origin", false).unwrap();
    a.fetch("origin").unwrap();
    let info = a.quick_status().unwrap();
    assert_eq!((info.ahead, info.behind), (Some(0), Some(1)));
    assert_eq!(info.format("%A%D"), "-1");
    let _ = origin;
}

#[test]
fn lazy_blobs_are_fetched_on_first_read() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let origin_dir = root.join("origin");
    let origin = Repo::init(&origin_dir)
        .unwrap()
        .with_home(root.join("home"));
    let url = origin_dir.to_string_lossy().to_string();
    let big: Vec<u8> = (0..200_000u32).map(|i| (i % 251) as u8).collect(); // has NUL bytes: opaque
    write(&origin_dir, "big.bin", &big);
    write(&origin_dir, "small.bin", &[0u8, 1, 2]);
    write(&origin_dir, "t.txt", b"t\n");
    let h = origin.commit("blobs", &[]).unwrap();
    let big_ref = Repo::blob_ref(&big);

    // Fetch only (no checkout) with a filter: the big blob stays absent.
    let a = Repo::init_with_id(&root.join("a"), origin.id().unwrap())
        .unwrap()
        .with_home(root.join("home"));
    let a = {
        let mut a = a;
        a.config.set("remote.origin.url", &url).unwrap();
        a.config.set("filter.max-blob", "100K").unwrap();
        a.save_config().unwrap();
        a
    };
    assert_eq!(a.config.max_blob, Some(100 * 1024));
    a.fetch("origin").unwrap();
    assert!(a.store().has(&h));
    assert!(!a.store().has(&big_ref), "withheld");
    assert!(
        a.store().has(&Repo::blob_ref(&[0u8, 1, 2])),
        "small blob came along"
    );
    assert_eq!(a.lazy_remote(&big_ref).as_deref(), Some("origin"));

    // status and commit do not need it: adopt the state, edit a text file, commit.
    let (op_ref, op) = a.head_op().unwrap();
    let mut view = op.view.clone();
    view.bookmarks.insert(
        "main".into(),
        a.store().put_state(&StateObject::new(vec![h])).unwrap(),
    );
    a.record_op(&[op_ref], "adopt", view).unwrap();
    // Checkout reads the blob lazily, which fetches it.
    a.checkout(&[h], true, "checkout").unwrap();
    assert!(a.store().has(&big_ref), "fetched on first read");
    assert_eq!(fs::read(root.join("a/big.bin")).unwrap(), big);
    assert!(a.lazy_remote(&big_ref).is_none(), "no longer registered");
    write(&root.join("a"), "t.txt", b"t2\n");
    a.commit("text edit", &[]).unwrap();

    // clone --max-blob records the filter; the checkout fetches lazily.
    let b = Repo::clone_with(&url, &root.join("b"), Some(1024), &[]).unwrap();
    assert_eq!(b.config.max_blob, Some(1024));
    assert_eq!(fs::read(root.join("b/big.bin")).unwrap(), big);
    assert_eq!(parse_size("2M").unwrap(), 2 << 20);
    assert!(parse_size("lots").is_err());
}

#[test]
fn sparse_checkout_materializes_only_chosen_paths() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let origin_dir = root.join("origin");
    let origin = Repo::init(&origin_dir)
        .unwrap()
        .with_home(root.join("home"));
    write(&origin_dir, "src/main.rs", b"fn main() {}\n");
    write(&origin_dir, "src/lib.rs", b"pub fn a() {}\n");
    write(&origin_dir, "docs/guide.md", b"# guide\n");
    let logo: Vec<u8> = (0..50_000u32).map(|i| (i % 7) as u8).collect();
    write(&origin_dir, "docs/logo.png", &logo);
    write(&origin_dir, "README.md", b"# top\n");
    let h1 = origin.commit("tree", &[]).unwrap();
    let url = origin_dir.to_string_lossy().to_string();

    let a = Repo::clone_with(&url, &root.join("a"), None, &["src".into()])
        .unwrap()
        .with_home(root.join("home"));
    assert_eq!(a.config.sparse_paths, vec!["src"]);
    assert_eq!(a.config.max_blob, Some(0), "sparse implies lazy blobs");
    assert!(root.join("a/src/main.rs").exists());
    assert!(!root.join("a/docs").exists() && !root.join("a/README.md").exists());
    assert!(
        !a.store().has(&Repo::blob_ref(&logo)),
        "out-of-scope blob never fetched"
    );
    assert!(
        !a.snapshot("status").unwrap().changed,
        "out-of-scope files are not removals"
    );
    assert_eq!(a.quick_status().unwrap().dirty, false);

    // Edits in scope commit normally and keep the rest of the tree intact.
    write(
        &root.join("a"),
        "src/lib.rs",
        b"pub fn a() {}\npub fn b() {}\n",
    );
    let h2 = a.commit("edit lib", &[]).unwrap();
    let st = a.load_state(&[h2]).unwrap().materialize();
    assert!(
        st.files.contains_key("docs/guide.md"),
        "the state still has everything"
    );
    assert!(a.push("origin", false).unwrap()[0].ok);
    // Files created outside the scope are ignored by status.
    write(&root.join("a"), "docs/new.md", b"ignored\n");
    assert!(a.snapshot("status").unwrap().statuses.is_empty());

    // Widening the filter checks out the rest; narrowing leaves stray files alone.
    let mut a = a;
    a.config.set("filter.paths", "src,docs").unwrap();
    a.save_config().unwrap();
    let r = a
        .checkout(&a.bookmark_heads().unwrap(), true, "widen")
        .unwrap();
    assert!(r.written >= 2);
    assert_eq!(
        fs::read(root.join("a/docs/logo.png")).unwrap(),
        logo,
        "now fetched lazily"
    );
    assert!(!root.join("a/README.md").exists());
    // Origin sees the change made under a sparse checkout with the full tree intact.
    origin.pull("origin").err();
    let full = origin
        .load_state(&origin.bookmark_heads().unwrap())
        .unwrap()
        .materialize();
    assert!(
        matches!(&full.files["src/lib.rs"].content, FileContent::Text { bytes, .. } if bytes == b"pub fn a() {}\npub fn b() {}\n")
    );
    assert!(full.files.contains_key("README.md"));
    let _ = h1;
}

#[test]
fn shallow_clone_and_deepen() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let origin_dir = root.join("origin");
    let origin = Repo::init(&origin_dir)
        .unwrap()
        .with_home(root.join("home"));
    let mut hashes = Vec::new();
    for i in 0..8 {
        write(
            &origin_dir,
            "a.txt",
            format!(
                "{}\n",
                (0..=i)
                    .map(|k| k.to_string())
                    .collect::<Vec<_>>()
                    .join("\n")
            )
            .as_bytes(),
        );
        hashes.push(origin.commit(&format!("c{i}"), &[]).unwrap());
    }
    let url = origin_dir.to_string_lossy().to_string();
    let a = Repo::clone_shallow(&url, &root.join("a"), 3, None, &[])
        .unwrap()
        .with_home(root.join("home"));
    assert!(a.is_shallow());
    assert_eq!(
        fs::read_to_string(root.join("a/a.txt")).unwrap(),
        "0\n1\n2\n3\n4\n5\n6\n7\n"
    );
    assert!(
        a.store().has(&hashes[7]) && a.store().has(&hashes[5]),
        "three levels present"
    );
    assert!(!a.store().has(&hashes[4]), "beyond the depth is absent");
    assert_eq!(a.boundary(), [hashes[4]].into_iter().collect());
    assert_eq!(
        a.log().unwrap().len(),
        9,
        "the log shows every change from the checkpoint's metadata"
    );
    assert!(!a.snapshot("status").unwrap().changed);
    assert_eq!(a.quick_status().unwrap().heads, 1);

    // Work continues on top of the shallow history and pushes back.
    write(&root.join("a"), "a.txt", b"0\n1\n2\n3\n4\n5\n6\n7\n8\n");
    let h_new = a.commit("c8", &[]).unwrap();
    assert!(a.push("origin", false).unwrap()[0].ok);
    assert_eq!(origin.bookmark_heads().unwrap(), vec![h_new]);
    // Fetching new work from origin into the shallow clone works too.
    write(&origin_dir, "b.txt", b"b\n");
    origin.pull("origin").err();
    let (_, wc) = origin.working_copy().unwrap();
    let _ = wc;
    origin
        .checkout(&origin.bookmark_heads().unwrap(), true, "co")
        .unwrap();
    write(&origin_dir, "b.txt", b"b\n");
    let h_b = origin.commit("b", &[]).unwrap();
    let pr = a.pull("origin").unwrap();
    assert!(pr.changed);
    assert!(a.store().has(&h_b));
    assert!(root.join("a/b.txt").exists());

    // Deepening fetches older history until the boundary is gone.
    // Every commit also depends on the change that created the file, so two
    // levels below the boundary hold h4, h3, and the root.
    assert!(a.deepen("origin", 2).unwrap() >= 2);
    assert!(a.store().has(&hashes[3]));
    assert!(a.is_shallow());
    a.deepen("origin", 100).unwrap();
    assert!(!a.is_shallow(), "boundary reached the root");
    assert!(a.store().has(&hashes[0]));
    assert_eq!(
        a.load_state_full(&a.bookmark_heads().unwrap())
            .unwrap()
            .len(),
        10
    );
}

#[test]
fn tags_are_immutable_named_states_and_travel() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let origin = Repo::init(&root.join("origin")).unwrap();
    let url = root.join("origin").to_string_lossy().to_string();
    let mut a = Repo::clone(&url, &root.join("a"))
        .unwrap()
        .with_home(root.join("home-a"));
    let (key_a, _) = a
        .create_identity("Ada", "[email protected]", IdentityScope::User)
        .unwrap();
    write(&root.join("a"), "f.txt", b"1\n");
    let h1 = a.commit("one", &[]).unwrap();
    write(&root.join("a"), "f.txt", b"1\n2\n");
    let h2 = a.commit("two", &[]).unwrap();

    let t = a.tag_create("v1", &[h1], "first release").unwrap();
    assert_eq!(
        (t.heads.clone(), t.signer.as_deref()),
        (vec![h1], Some("Ada"))
    );
    assert!(a.tag_create("v1", &[h2], "").is_err(), "immutable");
    assert!(a.tag_create("bad/name", &[h2], "").is_err());
    assert_eq!(a.tag_heads("v1").unwrap(), Some(vec![h1]));
    assert_eq!(a.resolve_heads("v1").unwrap(), vec![h1]);
    assert_eq!(a.resolve_heads("main").unwrap(), vec![h2]);
    let (_, sa) = a.tag_attest("v1").unwrap().unwrap();
    assert_eq!(sa.sigs[0].key, key_a);
    // Checkout by tag.
    a.checkout(&a.resolve_heads("v1").unwrap(), false, "co")
        .unwrap();
    assert_eq!(fs::read(root.join("a/f.txt")).unwrap(), b"1\n");
    a.checkout(&a.bookmark_heads().unwrap(), false, "co")
        .unwrap();

    // Push carries the tag; a second attestation for the name is refused.
    let r = a.push("origin", false).unwrap();
    assert!(r.iter().any(|x| x.name == "tags/v1" && x.ok), "{r:?}");
    assert_eq!(origin.tag_heads("v1").unwrap(), Some(vec![h1]));
    let mut forged = a
        .tag_refs()
        .unwrap()
        .into_iter()
        .find(|t| t.name == "v1")
        .unwrap();
    forged.state = origin
        .store()
        .put_state(&StateObject::new(vec![h2]))
        .unwrap();
    forged.heads = vec![h2];
    forged.attestation = None;
    let r = origin
        .receive_push(Bundle::default(), vec![], None, vec![forged])
        .unwrap();
    assert!(!r[0].ok && r[0].reason.contains("immutable"), "{r:?}");

    // A clone gets the tag; a later tag arrives on fetch.
    let b = Repo::clone(&url, &root.join("b"))
        .unwrap()
        .with_home(root.join("home-b"));
    assert_eq!(b.tag_heads("v1").unwrap(), Some(vec![h1]));
    assert!(b.tags().unwrap()[0].signer.as_deref() == Some("Ada"));
    a.tag_create("v2", &[h2], "second").unwrap();
    a.push("origin", false).unwrap();
    let rep = b.fetch("origin").unwrap();
    assert_eq!(rep.new_tags, 1);
    assert_eq!(b.tag_heads("v2").unwrap(), Some(vec![h2]));

    // Under a policy, an unattested tag is refused and an attested one by the root passes.
    a.policy_init().unwrap();
    a.push("origin", false).unwrap();
    let unattested = crate::protocol::TagRef {
        name: "v3".into(),
        state: origin
            .store()
            .put_state(&StateObject::new(vec![h2]))
            .unwrap(),
        heads: vec![h2],
        attestation: None,
    };
    let r = origin
        .receive_push(Bundle::default(), vec![], None, vec![unattested])
        .unwrap();
    assert!(!r[0].ok && r[0].reason.contains("attestation"), "{r:?}");
    a.tag_create("v3", &[h2], "").unwrap();
    let r = a.push("origin", false).unwrap();
    assert!(r.iter().any(|x| x.name == "tags/v3" && x.ok), "{r:?}");
    assert!(a.gc(true).is_ok());
    assert_eq!(a.tags().unwrap().len(), 3, "tags survive gc");
}

#[test]
fn multiple_workspaces_share_a_repository() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let main_dir = root.join("main");
    let repo = Repo::init(&main_dir).unwrap().with_home(root.join("home"));
    write(&main_dir, "a.txt", b"a\n");
    let h1 = repo.commit("a", &[]).unwrap();
    assert_eq!(repo.workspaces().unwrap().len(), 1);

    // A second workspace elsewhere, checked out on the bookmark.
    let ws_dir = root.join("ws2");
    let ws = repo.workspace_add(&ws_dir, None).unwrap();
    assert!(ws_dir.join(".oxy").is_file());
    assert_eq!(fs::read(ws_dir.join("a.txt")).unwrap(), b"a\n");
    assert_ne!(ws.workspace(), repo.workspace());
    let list = repo.workspaces().unwrap();
    assert_eq!(list.len(), 2);
    assert!(list
        .iter()
        .any(|w| w.id == ws.workspace() && w.path == ws_dir.canonicalize().unwrap() && !w.current));
    assert!(!ws.snapshot("status").unwrap().changed);

    // Work in the second workspace: its own working copy, shared bookmark.
    write(&ws_dir, "b.txt", b"b\n");
    let s = ws.snapshot("status").unwrap();
    assert_eq!(s.statuses.len(), 1);
    assert!(
        !repo.snapshot("status").unwrap().changed,
        "the first workspace is untouched"
    );
    let h2 = ws.commit("b from ws2", &[]).unwrap();
    let mut heads = repo.bookmark_heads().unwrap();
    heads.sort();
    let mut want = vec![h1, h2];
    want.sort();
    assert_eq!(heads, want, "both workspaces see the bookmark move");
    assert!(!main_dir.join("b.txt").exists());
    repo.checkout(&repo.bookmark_heads().unwrap(), false, "co")
        .unwrap();
    assert!(main_dir.join("b.txt").exists());

    // Reopening from inside the second workspace finds the shared repository.
    let reopened = Repo::open(&ws_dir).unwrap();
    assert_eq!(reopened.workspace(), ws.workspace());
    assert_eq!(reopened.id().unwrap(), repo.id().unwrap());
    assert_eq!(reopened.quick_status().unwrap().heads, 2);

    // Workspaces cannot nest; forget drops one from the view but keeps files.
    assert!(repo.workspace_add(&main_dir.join("inner"), None).is_err());
    assert!(repo.workspace_forget(&repo.workspace()).is_err());
    repo.workspace_forget(&ws.workspace()).unwrap();
    assert_eq!(repo.workspaces().unwrap().len(), 1);
    assert!(ws_dir.join("b.txt").exists());
    assert!(
        ws.snapshot("status").is_err(),
        "a forgotten workspace is no longer in the view"
    );

    // The snapshot lock: a fresh lock blocks a second, a stale one is taken over.
    let lock = repo.lock_snapshot().unwrap();
    drop(lock);
    let lock_path = main_dir
        .join(".oxy/workspaces")
        .join(repo.workspace().to_hex())
        .join("lock");
    fs::write(&lock_path, "1").unwrap();
    let old = std::time::SystemTime::now() - std::time::Duration::from_secs(120);
    fs::File::open(&lock_path)
        .unwrap()
        .set_modified(old)
        .unwrap();
    assert!(repo.lock_snapshot().is_ok(), "stale lock taken over");
}

#[test]
fn attributes_binary_eol_nocompress_lockable() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap().with_home(root.join("home"));
    write(
        root,
        ".oxyattributes",
        b"*.dat binary nocompress\n*.txt eol=crlf\nassets/** lockable\n",
    );
    write(root, "plain.dat", b"no nul bytes here\n");
    write(root, "notes.txt", b"one\r\ntwo\r\n");
    write(root, "assets/model.bin", b"\0model");
    let h = repo.commit("attrs", &[]).unwrap();
    let snap = repo.load_state(&[h]).unwrap().materialize();
    assert!(
        snap.files["plain.dat"].mode.opaque,
        "binary attribute forces opaque without NUL bytes"
    );
    assert!(
        matches!(&snap.files["notes.txt"].content, FileContent::Text { bytes, .. } if bytes == b"one\ntwo\n"),
        "stored with LF"
    );
    assert!(
        !repo.snapshot("status").unwrap().changed,
        "CRLF on disk equals LF in the state"
    );
    // nocompress chunks pack raw.
    let r = repo.gc(true).unwrap();
    assert!(r.packed.objects > 0);
    // Checkout writes CRLF for eol=crlf and makes lockable files read-only.
    fs::remove_file(root.join("notes.txt")).unwrap();
    repo.checkout(&[h], true, "co").unwrap();
    assert_eq!(fs::read(root.join("notes.txt")).unwrap(), b"one\r\ntwo\r\n");
    assert!(fs::metadata(root.join("assets/model.bin"))
        .unwrap()
        .permissions()
        .readonly());
    assert!(repo.lock_path("plain.dat").is_err(), "not lockable");
    repo.lock_path("assets/model.bin").unwrap();
    assert!(!fs::metadata(root.join("assets/model.bin"))
        .unwrap()
        .permissions()
        .readonly());
    assert!(repo.is_locked("assets/model.bin"));
    write(root, "assets/model.bin", b"\0model2");
    repo.commit("edit model", &[]).unwrap();
    repo.unlock_path("assets/model.bin").unwrap();
    assert!(fs::metadata(root.join("assets/model.bin"))
        .unwrap()
        .permissions()
        .readonly());
    // A later checkout can still overwrite a read-only lockable file.
    repo.checkout(&[h], true, "co").unwrap();
    assert_eq!(fs::read(root.join("assets/model.bin")).unwrap(), b"\0model");
}

#[cfg(unix)]
#[test]
fn hooks_can_veto_observe_and_add_dependencies() {
    use std::os::unix::fs::PermissionsExt;
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let mut repo = Repo::init(root).unwrap().with_home(root.join("home"));
    let hooks = root.join(".oxy/hooks");
    fs::create_dir_all(&hooks).unwrap();
    let hook = |name: &str, body: &str| {
        let p = hooks.join(name);
        fs::write(&p, format!("#!/bin/sh\n{body}\n")).unwrap();
        fs::set_permissions(&p, fs::Permissions::from_mode(0o755)).unwrap();
    };
    hook("pre-commit", "cat > \"$OXY_ROOT/.last-pre-commit\"; grep -q WIP \"$OXY_ROOT/.last-pre-commit\" && { echo 'no WIP commits' >&2; exit 1; }; exit 0");
    hook("post-commit", "cat > \"$OXY_ROOT/.last-post-commit\"");
    hook("post-checkout", "cat > \"$OXY_ROOT/.last-post-checkout\"");
    hook("pre-push", "echo pushing blocked >&2; exit 3");
    write(root, ".oxyignore", b".last-*\n");
    write(root, "a.txt", b"a\n");
    let err = repo.commit("WIP: nope", &[]).unwrap_err().to_string();
    assert!(err.contains("pre-commit refused: no WIP commits"), "{err}");
    let h1 = repo.commit("first", &[]).unwrap();
    let pre = fs::read_to_string(root.join(".last-pre-commit")).unwrap();
    assert!(
        pre.contains("\"event\":\"pre-commit\"")
            && pre.contains("\"path\":\"a.txt\"")
            && pre.contains("\"message\":\"first\""),
        "{pre}"
    );
    let post = fs::read_to_string(root.join(".last-post-commit")).unwrap();
    assert!(post.contains(&h1.to_hex()), "{post}");
    repo.checkout(&[h1], false, "co").unwrap();
    assert!(fs::read_to_string(root.join(".last-post-checkout"))
        .unwrap()
        .contains("post-checkout"));
    repo.config.set("remote.origin.url", "/nowhere").unwrap();
    repo.save_config().unwrap();
    let err = repo.push("origin", false).unwrap_err().to_string();
    assert!(err.contains("pre-push refused: pushing blocked"), "{err}");

    // semantic-deps: only when enabled; adds an explicit dependency.
    write(root, "b.txt", b"b\n");
    hook(
        "semantic-deps",
        &format!(
            "cat > \"$OXY_ROOT/.last-semantic\"; echo '{{\"deps\": [\"{}\"]}}'",
            h1.to_hex()
        ),
    );
    let h2 = repo.commit("b without hook", &[]).unwrap();
    assert!(
        repo.store().get_change(&h2).unwrap().deps.is_empty(),
        "hook disabled by default"
    );
    repo.config.set("hooks.semantic-deps", "true").unwrap();
    repo.save_config().unwrap();
    write(root, "c.txt", b"c\n");
    let h3 = repo.commit("c with hook", &[]).unwrap();
    assert_eq!(repo.store().get_change(&h3).unwrap().deps, vec![h1]);
    let sem = fs::read_to_string(root.join(".last-semantic")).unwrap();
    assert!(
        sem.contains("\"touched_paths\":[\"c.txt\"]") && sem.contains("candidate_deps"),
        "{sem}"
    );
    assert_eq!(json_str("a\"b\\c\n"), "\"a\\\"b\\\\c\\n\"");
}

#[test]
fn amend_into_older_change_and_split() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let mut repo = Repo::init(root).unwrap().with_home(root.join("home"));
    repo.create_identity("Ada", "a@b", IdentityScope::User)
        .unwrap();
    repo.set_user_config("core.sign", "change").unwrap();
    write(root, "a.txt", b"one\ntwo\n");
    let h0 = repo.commit("base", &[]).unwrap();
    write(root, "a.txt", b"one\nTWO\n");
    let h1 = repo.commit("edit two", &[]).unwrap();
    write(root, "a.txt", b"one\nTWO\nthree\n");
    let h2 = repo.commit("add three", &[]).unwrap();
    let id1 = repo.store().get_change(&h1).unwrap().change_id;

    // Fixing the line h1 introduced folds into h1; h2 is rewritten on top.
    write(root, "a.txt", b"one\nTWO!\nthree\n");
    let h1b = repo.amend_into(&h1, None).unwrap();
    assert_ne!(h1b, h1);
    let c1b = repo.store().get_change(&h1b).unwrap();
    assert_eq!(c1b.change_id, id1);
    assert_eq!(c1b.deps, vec![h0]);
    assert!(matches!(
        repo.verify_change(&h1b).unwrap(),
        SignatureStatus::Valid { .. }
    ));
    let heads = repo.bookmark_heads().unwrap();
    assert_eq!(heads.len(), 1);
    let top = repo.store().get_change(&heads[0]).unwrap();
    assert_eq!(top.message, "add three");
    assert_eq!(
        top.deps.iter().copied().collect::<BTreeSet<_>>(),
        [h0, h1b].into_iter().collect(),
        "depends on the file's creator and the rewritten line"
    );
    let snap = repo.load_state(&heads).unwrap().materialize();
    assert!(
        matches!(&snap.files["a.txt"].content, FileContent::Text { bytes, .. } if bytes == b"one\nTWO!\nthree\n")
    );
    assert!(
        !repo.snapshot("status").unwrap().changed,
        "the working copy is clean after folding"
    );
    // Only h1b's own state shows the fix without "three".
    let only = repo.load_state(&[h1b]).unwrap().materialize();
    assert!(
        matches!(&only.files["a.txt"].content, FileContent::Text { bytes, .. } if bytes == b"one\nTWO!\n")
    );
    assert_eq!(repo.log().unwrap().len(), 4);

    // An edit to a line introduced by h2 cannot fold into h1.
    write(root, "a.txt", b"one\nTWO!\nthree!\n");
    let err = repo.amend_into(&h1b, None).unwrap_err().to_string();
    assert!(err.contains("introduced after"), "{err}");
    assert!(
        repo.snapshot("status").unwrap().statuses.len() == 1,
        "nothing was changed by the refusal"
    );
    write(root, "a.txt", b"one\nTWO!\nthree\n");

    // Split the head that touches two files.
    write(root, "b.txt", b"b\n");
    write(root, "c.txt", b"c\n");
    let h3 = repo.commit("b and c", &[]).unwrap();
    let id3 = repo.store().get_change(&h3).unwrap().change_id;
    let (p1, p2) = repo.split(&h3, &["b.txt".into()]).unwrap();
    let c_1 = repo.store().get_change(&p1).unwrap();
    let c_2 = repo.store().get_change(&p2).unwrap();
    assert!(c_1.message.contains("part 1: b.txt"));
    assert_eq!(c_2.change_id, id3);
    let heads: BTreeSet<_> = repo.bookmark_heads().unwrap().into_iter().collect();
    assert!(
        heads.contains(&p1) && heads.contains(&p2),
        "independent parts are both heads"
    );
    let snap = repo
        .load_state(&repo.bookmark_heads().unwrap())
        .unwrap()
        .materialize();
    assert!(snap.files.contains_key("b.txt") && snap.files.contains_key("c.txt"));
    let only1 = repo.load_state(&[p1]).unwrap().materialize();
    assert!(only1.files.contains_key("b.txt") && !only1.files.contains_key("c.txt"));
    assert!(!repo.snapshot("status").unwrap().changed);
    assert!(repo.split(&p2, &["nope.txt".into()]).is_err());
    let _ = h2;
}

#[test]
fn identity_lifecycle() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let origin = Repo::init(&root.join("origin")).unwrap();
    let url = root.join("origin").to_string_lossy().to_string();
    let mut a = Repo::clone(&url, &root.join("a"))
        .unwrap()
        .with_home(root.join("home-a"));
    a.set_user_config("core.sign", "change").unwrap();
    let (key_a, _) = a
        .create_identity("Ada", "[email protected]", IdentityScope::User)
        .unwrap();
    write(&root.join("a"), "a.txt", b"a\n");
    let h1 = a.commit("one", &[]).unwrap();
    assert!(a.policy_init().unwrap().applied);
    assert!(a.push("origin", false).unwrap().iter().all(|r| r.ok));

    // Expiry: an identity that had expired when the change was made does not authenticate it.
    let mut e = Repo::init(&root.join("e"))
        .unwrap()
        .with_home(root.join("home-e"));
    e.set_user_config("core.sign", "change").unwrap();
    e.create_identity_with(
        "Eve",
        "[email protected]",
        IdentityScope::User,
        Some(Hlc::now().wall_ms - 1),
    )
    .unwrap();
    write(&root.join("e"), "e.txt", b"e\n");
    let he = e.commit("late", &[]).unwrap();
    assert!(
        matches!(e.verify_change(&he).unwrap(), SignatureStatus::Invalid(m) if m.contains("expired"))
    );
    // Renewal re-issues the identity (same keys, new KeyId) with a later expiry.
    let r = e
        .renew_identity(Some(Hlc::now().wall_ms + 86_400_000))
        .unwrap();
    assert_eq!(e.identity(&r.new).unwrap().previous, Some(r.old));
    write(&root.join("e"), "e.txt", b"e2\n");
    let he2 = e.commit("in time", &[]).unwrap();
    assert!(
        matches!(e.verify_change(&he2).unwrap(), SignatureStatus::Valid { key, .. } if key == r.new)
    );

    // Rotation: a fresh key; the old change still verifies; the policy follows.
    let r = a.rotate_identity().unwrap();
    assert_eq!(r.old, key_a);
    assert_eq!(a.config.author_key, Some(r.new));
    assert_eq!(a.identity(&r.new).unwrap().previous, Some(key_a));
    assert!(r.policy.as_ref().unwrap().applied);
    let (_, sp) = a.current_policy().unwrap().unwrap();
    assert_eq!(
        (sp.policy.serial, sp.policy.roots.clone()),
        (2, vec![r.new])
    );
    assert!(
        !sp.policy.revoked.contains(&key_a) && sp.policy.authorizes(&r.new, "main"),
        "superseded, not revoked"
    );
    assert!(sp.policy.succeeds(&r.new, &key_a) && !sp.policy.succeeds(&key_a, &r.new));
    assert!(
        matches!(a.verify_change(&h1).unwrap(), SignatureStatus::Valid { key, revoked: false, .. } if key == key_a)
    );
    write(&root.join("a"), "a.txt", b"a2\n");
    let h2 = a.commit("two", &[]).unwrap();
    assert!(
        matches!(a.verify_change(&h2).unwrap(), SignatureStatus::Valid { key, revoked: false, .. } if key == r.new)
    );
    // Origin accepts the rotated policy (signed by the old root) and the new key's change.
    let res = a.push("origin", false).unwrap();
    assert!(res.iter().all(|x| x.ok), "{res:?}");
    assert_eq!(origin.current_policy().unwrap().unwrap().1.policy.serial, 2);
    let key_a = r.new;

    // Delegation: Bob may sign on Ada's behalf. Delegates live in the
    // identity object, so Ada's KeyId changes while her keys stay the same.
    let mut b = Repo::clone(&url, &root.join("b"))
        .unwrap()
        .with_home(root.join("home-b"));
    let (key_b, id_b) = b
        .create_identity("Bob", "[email protected]", IdentityScope::User)
        .unwrap();
    let r = a.delegate_add(id_b.clone()).unwrap();
    assert_eq!(r.old, key_a);
    let key_a2 = r.new;
    assert_eq!(a.identity(&key_a2).unwrap().delegates, vec![key_b]);
    assert_eq!(
        a.identity(&key_a2).unwrap().ed25519_pk,
        a.identity(&key_a).unwrap().ed25519_pk
    );
    assert!(a.delegate_add(id_b.clone()).is_err(), "already a delegate");
    assert!(a.push("origin", false).unwrap().iter().all(|x| x.ok));
    write(&root.join("a"), "a.txt", b"a3\n");
    let h3 = a.commit("three", &[]).unwrap();
    assert!(
        matches!(a.verify_change(&h3).unwrap(), SignatureStatus::Valid { key, .. } if key == key_a2),
        "the same secret signs under the new KeyId"
    );
    // A change authored by Ada but signed only by Bob verifies through the delegation.
    a.set_user_config("core.sign", "seal").unwrap();
    write(&root.join("a"), "a.txt", b"a4\n");
    let h4 = a.commit("four", &[]).unwrap();
    assert_eq!(a.verify_change(&h4).unwrap(), SignatureStatus::Unsigned);
    let (_, sk_b) = b.secret_key().unwrap().unwrap();
    a.store()
        .put_signature(&h4, &sk_b.sign(Domain::Change, &key_b, &h4))
        .unwrap();
    assert!(
        matches!(a.verify_change(&h4).unwrap(), SignatureStatus::Valid { key, .. } if key == key_b)
    );
    a.set_user_config("core.sign", "change").unwrap();
    // Withdrawing the delegation re-issues the identity again.
    let r = a.delegate_remove(&key_b).unwrap();
    assert!(a.identity(&r.new).unwrap().delegates.is_empty());
    assert!(a.delegate_remove(&key_b).is_err());
    let key_a3 = r.new;
    let res = a.push("origin", false).unwrap();
    assert!(res.iter().all(|x| x.ok), "{res:?}");

    // Multi-signer policy: Bob becomes a root and the threshold rises to 2,
    // both applied under the old threshold of 1. A grant then needs Bob too.
    assert!(a.policy_root_add(id_b.clone()).unwrap().applied);
    assert!(a.policy_root_add(id_b.clone()).is_err());
    assert!(a.policy_set_threshold(3).is_err());
    assert!(a.policy_set_threshold(2).unwrap().applied);
    assert!(a.push("origin", false).unwrap().iter().all(|x| x.ok));
    b.pull("origin").unwrap();
    assert_eq!(
        b.current_policy().unwrap().unwrap().1.policy.root_threshold,
        2
    );
    let mut c = Repo::init(&root.join("c"))
        .unwrap()
        .with_home(root.join("home-c"));
    let (key_c, id_c) = c
        .create_identity("Cy", "[email protected]", IdentityScope::User)
        .unwrap();
    let serial_before = a.current_policy().unwrap().unwrap().1.policy.serial;
    let proposal = a.policy_grant(id_c, None).unwrap();
    assert!(!proposal.applied && proposal.sigs.len() == 1);
    assert_eq!(proposal.policy.serial, serial_before + 1);
    assert_eq!(
        a.current_policy().unwrap().unwrap().1.policy.serial,
        serial_before,
        "a proposal changes nothing yet"
    );
    // Bob signs the proposal, handed over as a file, and it applies for him.
    let bytes = proposal.signed().encode();
    let signed = b
        .policy_sign(SignedPolicy::decode(&bytes).unwrap())
        .unwrap();
    assert!(signed.applied && signed.sigs.len() == 2);
    assert!(b
        .current_policy()
        .unwrap()
        .unwrap()
        .1
        .policy
        .authorizes(&key_c, "main"));
    assert!(
        b.policy_sign(signed.signed()).is_err(),
        "a stale proposal is refused"
    );
    // Bob publishes it and Ada picks it up.
    assert!(b
        .push("origin", false)
        .unwrap()
        .iter()
        .any(|x| x.name == "policy" && x.ok));
    a.pull("origin").unwrap();
    assert_eq!(
        a.current_policy().unwrap().unwrap().1.policy.serial,
        serial_before + 1
    );
    // A root cannot revoke itself; revoking Cy needs both roots but is recorded locally at once.
    assert!(a.policy_revoke(&key_a3).is_err());
    let u = a
        .revoke_identity(&key_c, "left the project")
        .unwrap()
        .unwrap();
    assert!(!u.applied);
    assert!(a.is_revoked(&key_c).unwrap());
    assert!(!b.is_revoked(&key_c).unwrap());
    let u = b.policy_sign(u.signed()).unwrap();
    assert!(u.applied && u.policy.is_revoked(&key_c));
    assert!(b.is_revoked(&key_c).unwrap());
    // Bob can revoke Ada's root key, leaving himself as the only root (threshold 2 would be unmeetable).
    assert!(
        b.policy_revoke(&key_a3).is_err(),
        "would leave one root for a threshold of 2"
    );
    // Revoking one's own key without a policy root works locally: a plain marker plus attestation.
    let key_c_own = c.config.author_key.unwrap();
    assert!(c
        .revoke_identity(&key_c_own, "lost laptop")
        .unwrap()
        .is_none());
    assert!(c.is_revoked(&key_c_own).unwrap());
    assert_eq!(key_c_own, key_c);
}

#[test]
fn renames_are_detected_and_tracked_as_moves() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap().with_home(root.join("home"));
    write(
        root,
        "src/old.rs",
        b"fn a() {}\nfn b() {}\nfn c() {}\nfn d() {}\n",
    );
    write(root, "img.bin", b"\x89PNG\0\0\x01\x02");
    write(root, "tiny.txt", b"x\n");
    let h1 = repo.commit("base", &[]).unwrap();
    let node_old = repo.load_state(&[h1]).unwrap().materialize().files["src/old.rs"].node;
    let node_img = repo.load_state(&[h1]).unwrap().materialize().files["img.bin"].node;

    // Rename with a small edit, a binary moved unchanged, and a rewrite
    // that shares nothing with the removed file.
    fs::remove_file(root.join("src/old.rs")).unwrap();
    write(
        root,
        "lib/new.rs",
        b"fn a() {}\nfn b() {}\nfn c() {}\nfn e() {}\n",
    );
    fs::remove_file(root.join("img.bin")).unwrap();
    write(root, "assets/img.bin", b"\x89PNG\0\0\x01\x02");
    fs::remove_file(root.join("tiny.txt")).unwrap();
    write(root, "other.txt", b"completely different\n");
    let snap = repo.snapshot("status").unwrap();
    let statuses: Vec<(&str, ChangeStatus)> = snap
        .statuses
        .iter()
        .map(|s| (s.path.as_str(), s.status))
        .collect();
    assert_eq!(
        statuses,
        vec![
            ("assets/img.bin", ChangeStatus::Renamed),
            ("lib/new.rs", ChangeStatus::Renamed),
            ("other.txt", ChangeStatus::Added),
            ("src", ChangeStatus::Removed),
            ("tiny.txt", ChangeStatus::Removed)
        ]
    );
    let h2 = repo.commit("move things", &[]).unwrap();
    let c = repo.store().get_change(&h2).unwrap();
    let moves: Vec<_> = c
        .tree_ops
        .iter()
        .filter(|op| matches!(op, TreeOp::Move { .. }))
        .collect();
    assert_eq!(moves.len(), 2, "{:?}", c.tree_ops);
    assert!(c.tree_ops.iter().any(
        |op| matches!(op, TreeOp::Move { node, name, .. } if *node == node_old && name == "new.rs")
    ));
    assert!(c.tree_ops.iter().any(
        |op| matches!(op, TreeOp::Move { node, name, .. } if *node == node_img && name == "img.bin")
    ));
    let snap = repo.load_state(&[h2]).unwrap().materialize();
    assert_eq!(
        snap.files["lib/new.rs"].node, node_old,
        "the node survives the rename"
    );
    assert!(
        matches!(&snap.files["lib/new.rs"].content, FileContent::Text { bytes, .. } if bytes == b"fn a() {}\nfn b() {}\nfn c() {}\nfn e() {}\n")
    );
    assert!(!snap.files.contains_key("src/old.rs") && !snap.files.contains_key("src"));
    assert!(render_change(
        &c,
        &repo.load_state(&[h1]).unwrap(),
        &repo.load_state(&[h1]).unwrap().materialize()
    )
    .contains("R "));
    // A fresh checkout reproduces the tree.
    let other = tempfile::tempdir().unwrap();
    let clone = Repo::clone(&root.to_string_lossy(), other.path()).unwrap();
    assert_eq!(
        fs::read(other.path().join("lib/new.rs")).unwrap(),
        b"fn a() {}\nfn b() {}\nfn c() {}\nfn e() {}\n"
    );
    assert!(!other.path().join("src").exists());
    assert!(!clone.snapshot("status").unwrap().changed);
    // Similarity is line based, byte weighted.
    assert_eq!(similarity(b"a\nb\n", b"a\nb\n"), 100);
    assert_eq!(similarity(b"a\nb\nc\nd\n", b"a\nb\nx\ny\n"), 50);
    assert_eq!(similarity(b"hello\n", b"world\n"), 0);
    assert_eq!(similarity(b"", b"x\n"), 0);
}

#[test]
fn git_fetch_and_push_round_trip() {
    hermetic();
    if std::process::Command::new("git")
        .arg("--version")
        .output()
        .is_err()
    {
        eprintln!("git not installed; skipping");
        return;
    }
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let git_in = |d: &Path, args: &[&str]| -> String {
        let out = std::process::Command::new("git")
            .arg("-C")
            .arg(d)
            .args([
                "-c",
                "user.name=Grace",
                "-c",
                "[email protected]",
                "-c",
                "commit.gpgsign=false",
            ])
            .args(args)
            .output()
            .unwrap();
        assert!(
            out.status.success(),
            "git {args:?}: {}",
            String::from_utf8_lossy(&out.stderr)
        );
        String::from_utf8_lossy(&out.stdout).trim().to_string()
    };
    // A bare "remote" and a work tree that pushes to it.
    let remote = root.join("remote.git");
    fs::create_dir_all(&remote).unwrap();
    git_in(&remote, &["init", "-q", "--bare", "-b", "main"]);
    let work = root.join("work");
    git_in(
        root,
        &[
            "clone",
            "-q",
            remote.to_str().unwrap(),
            work.to_str().unwrap(),
        ],
    );
    git_in(&work, &["checkout", "-q", "-b", "main"]);
    write(&work, "README.md", b"# Project\n");
    write(&work, "src/lib.rs", b"pub fn a() {}\n");
    git_in(&work, &["add", "."]);
    git_in(&work, &["commit", "-q", "-m", "initial"]);
    write(&work, "src/lib.rs", b"pub fn a() {}\npub fn b() {}\n");
    git_in(&work, &["commit", "-q", "-am", "second"]);
    git_in(&work, &["push", "-q", "origin", "main"]);
    let tip1 = git_in(&work, &["rev-parse", "HEAD"]);

    // Fetch into a fresh oxy repository.
    let o = root.join("oxy");
    let mut repo = Repo::init(&o).unwrap().with_home(root.join("home"));
    repo.create_identity("Ada", "[email protected]", IdentityScope::User)
        .unwrap();
    let url = remote.to_string_lossy().to_string();
    let r = repo.git_fetch(&url, "main").unwrap();
    assert_eq!((r.commits, r.heads), (2, 1));
    assert_eq!(
        fs::read(o.join("src/lib.rs")).unwrap(),
        b"pub fn a() {}\npub fn b() {}\n"
    );
    assert!(!repo.snapshot("status").unwrap().changed);
    assert_eq!(
        repo.git_fetch(&url, "main").unwrap().commits,
        0,
        "nothing new"
    );

    // An oxy change, pushed back: one commit on top of the Git tip.
    write(
        &o,
        "src/lib.rs",
        b"pub fn a() {}\npub fn b() {}\npub fn c() {}\n",
    );
    write(&o, "NOTES.md", b"from oxy\n");
    let h_oxy = repo.commit("add c and notes", &[]).unwrap();
    let r = repo.git_push(&url, "main").unwrap();
    assert_eq!(r.exported, 1, "{r:?}");
    git_in(&work, &["pull", "-q", "--ff-only", "origin", "main"]);
    assert_eq!(
        git_in(&work, &["log", "--format=%s", "main"]),
        "add c and notes\nsecond\ninitial"
    );
    assert_eq!(git_in(&work, &["rev-parse", "HEAD~1"]), tip1);
    assert_eq!(fs::read(work.join("NOTES.md")).unwrap(), b"from oxy\n");
    assert_eq!(git_in(&work, &["log", "-1", "--format=%an", "main"]), "Ada");
    assert!(git_in(&work, &["log", "-1", "--format=%B", "main"])
        .contains(&format!("Oxy-Hash: {}", h_oxy.to_hex())));
    assert_eq!(
        repo.git_push(&url, "main").unwrap().exported,
        0,
        "already pushed"
    );

    // Git moves on; pushing without fetching is refused, fetching brings
    // the commit in and the working copy follows.
    write(&work, "README.md", b"# Project\n\nMore.\n");
    git_in(&work, &["commit", "-q", "-am", "readme from git"]);
    git_in(&work, &["push", "-q", "origin", "main"]);
    let tip2 = git_in(&work, &["rev-parse", "HEAD"]);
    assert!(repo
        .git_push(&url, "main")
        .unwrap_err()
        .to_string()
        .contains("fetch"));
    let r = repo.git_fetch(&url, "main").unwrap();
    assert_eq!(
        (r.commits, r.heads),
        (1, 2),
        "the Git change and the oxy change commute"
    );
    assert_eq!(
        fs::read(o.join("README.md")).unwrap(),
        b"# Project\n\nMore.\n"
    );
    assert_eq!(fs::read(o.join("NOTES.md")).unwrap(), b"from oxy\n");
    assert!(!repo.snapshot("status").unwrap().changed);
    // Another oxy change pushes on top of Git's newest commit.
    write(&o, "NOTES.md", b"from oxy\nagain\n");
    repo.commit("notes again", &[]).unwrap();
    assert_eq!(repo.git_push(&url, "main").unwrap().exported, 1);
    git_in(&work, &["pull", "-q", "--ff-only", "origin", "main"]);
    assert_eq!(git_in(&work, &["rev-parse", "HEAD~1"]), tip2);
    assert_eq!(
        fs::read(work.join("NOTES.md")).unwrap(),
        b"from oxy\nagain\n"
    );
    assert_eq!(
        git_in(&work, &["log", "--format=%s", "main"])
            .lines()
            .count(),
        5
    );
}

/// Benchmark, not a gate: `cargo test --release -p oxy-core --lib bench_one_gibibyte -- --ignored --nocapture`.
/// Commits, stores, clones, and reads back a 1 GiB incompressible file.
#[test]
#[ignore]
fn bench_one_gibibyte_file() {
    hermetic();
    // /tmp is often a small tmpfs; `OXY_BENCH_DIR` picks a roomier disk.
    let dir = match std::env::var_os("OXY_BENCH_DIR") {
        Some(d) => tempfile::tempdir_in(d).unwrap(),
        None => tempfile::tempdir().unwrap(),
    };
    let root = dir.path();
    let repo = Repo::init(&root.join("r"))
        .unwrap()
        .with_home(root.join("home"));
    let size = 1usize << 30;
    let mut data = vec![0u8; size];
    let mut x = 0x9e3779b97f4a7c15u64;
    for chunk in data.chunks_mut(8) {
        x ^= x << 13;
        x ^= x >> 7;
        x ^= x << 17;
        let b = x.to_le_bytes();
        chunk.copy_from_slice(&b[..chunk.len()]);
    }
    let t = std::time::Instant::now();
    write(&root.join("r"), "big.bin", &data);
    eprintln!("write 1 GiB to disk: {:.2?}", t.elapsed());
    let t = std::time::Instant::now();
    let h = repo.commit("big", &[]).unwrap();
    eprintln!("commit (chunk + hash + store): {:.2?}", t.elapsed());
    let t = std::time::Instant::now();
    assert!(!repo.snapshot("status").unwrap().changed);
    eprintln!("status on a clean 1 GiB working copy: {:.2?}", t.elapsed());
    let t = std::time::Instant::now();
    let objects = repo.store().list().unwrap().len();
    eprintln!("objects stored: {objects} ({:.2?} to list)", t.elapsed());
    let t = std::time::Instant::now();
    let g = repo.gc(true).unwrap();
    eprintln!("gc (pack): {:.2?} {g:?}", t.elapsed());
    let t = std::time::Instant::now();
    let clone = Repo::clone(&root.join("r").to_string_lossy(), &root.join("c")).unwrap();
    eprintln!("clone (fetch + checkout): {:.2?}", t.elapsed());
    let t = std::time::Instant::now();
    let back = fs::read(root.join("c/big.bin")).unwrap();
    assert_eq!(blake3::hash(&back), blake3::hash(&data));
    eprintln!("read back and verify: {:.2?}", t.elapsed());
    assert_eq!(clone.bookmark_heads().unwrap(), vec![h]);
    let store_bytes: u64 = walkdir_size(&root.join("r/.oxy/objects"));
    eprintln!(
        "store size: {:.1} MiB for 1 GiB of data",
        store_bytes as f64 / (1024.0 * 1024.0)
    );
}

fn walkdir_size(p: &Path) -> u64 {
    let mut total = 0;
    if let Ok(rd) = fs::read_dir(p) {
        for e in rd.flatten() {
            let path = e.path();
            if path.is_dir() {
                total += walkdir_size(&path);
            } else if let Ok(m) = fs::metadata(&path) {
                total += m.len();
            }
        }
    }
    total
}

/// An opaque file whose size and mtime match the manifest is not read on
/// the next snapshot: its blob comes from the manifest's stat cache.
#[cfg(unix)]
#[test]
fn stat_cache_skips_reading_unchanged_opaque_files() {
    use std::os::unix::fs::PermissionsExt;
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap().with_home(root.join("home"));
    let mut big = vec![0u8; 300 * 1024];
    for (i, b) in big.iter_mut().enumerate() {
        *b = (i as u32).wrapping_mul(2654435761).to_le_bytes()[1];
    }
    big[0] = 0;
    write(root, "big.bin", &big);
    write(root, "a.txt", b"text\n");
    let h1 = repo.commit("base", &[]).unwrap();
    let (_, _, m) = repo.read_manifest().unwrap().unwrap();
    assert!(
        m.entries["big.bin"].blob.is_some(),
        "opaque files record their blob"
    );
    assert!(m.entries["a.txt"].blob.is_none());
    let blob = m.entries["big.bin"].blob.unwrap();
    assert!(repo.store().has(&blob));

    // Files modified within two seconds of the manifest are racy and still
    // read; age the file so the cache applies, then snapshot to record it.
    let old = std::time::SystemTime::now() - std::time::Duration::from_secs(30);
    fs::File::options()
        .write(true)
        .open(root.join("big.bin"))
        .unwrap()
        .set_modified(old)
        .unwrap();
    assert!(!repo.snapshot("status").unwrap().changed);
    // Now the file cannot be read at all; the snapshot succeeds without it.
    fs::set_permissions(root.join("big.bin"), fs::Permissions::from_mode(0o000)).unwrap();
    let snap = repo.snapshot("status").unwrap();
    assert!(
        !snap.changed && snap.statuses.is_empty(),
        "{:?}",
        snap.statuses
    );
    fs::set_permissions(root.join("big.bin"), fs::Permissions::from_mode(0o644)).unwrap();
    // A real change (new mtime, new content) is seen and committed correctly.
    let mut big2 = big.clone();
    big2[10] ^= 0xff;
    write(root, "big.bin", &big2);
    let snap = repo.snapshot("status").unwrap();
    assert_eq!(
        snap.statuses
            .iter()
            .map(|s| (s.path.as_str(), s.status))
            .collect::<Vec<_>>(),
        vec![("big.bin", ChangeStatus::Modified)]
    );
    let h2 = repo.commit("edit", &[]).unwrap();
    let files = repo.load_state(&[h2]).unwrap().materialize().files;
    assert_eq!(
        files["big.bin"].content,
        FileContent::Opaque {
            blobs: vec![Repo::blob_ref(&big2)]
        }
    );
    // Checkout writes a manifest with blobs too, so the next status is cached.
    repo.checkout(&[h1], false, "checkout").unwrap();
    let (_, _, m) = repo.read_manifest().unwrap().unwrap();
    assert_eq!(m.entries["big.bin"].blob, Some(Repo::blob_ref(&big)));
    assert!(!repo.snapshot("status").unwrap().changed);
}

#[test]
fn status_json_lists_conflicts_with_contributors() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap().with_home(root.join("home"));
    write(root, "a.txt", b"one\n");
    let h1 = repo.commit("base", &[]).unwrap();
    write(root, "a.txt", b"one\nleft\n");
    let ha = repo.commit("left", &[]).unwrap();
    repo.checkout(&[h1], true, "checkout").unwrap();
    write(root, "a.txt", b"one\nright\n");
    let hb = repo.commit("right", &[]).unwrap();
    repo.checkout(&[ha, hb], true, "checkout").unwrap();
    let snap = repo.snapshot("status").unwrap();
    assert!(snap.base_snapshot.is_conflicted());
    let json = repo.status_json(&snap).unwrap();
    let ida = repo.store().get_change(&ha).unwrap().change_id.to_hex();
    let idb = repo.store().get_change(&hb).unwrap().change_id.to_hex();
    assert!(json.contains("\"conflicted\":true"), "{json}");
    assert!(
        json.contains("\"kind\":\"text\",\"path\":\"a.txt\""),
        "{json}"
    );
    assert!(json.contains(&ida) && json.contains(&idb), "{json}");
    assert!(json.contains("\"resolved\":false"), "{json}");
    assert!(json.starts_with('{') && json.ends_with('}'));
    // Resolve and the report says so; a clean copy has no conflicts.
    write(root, "a.txt", b"one\nleft\nright\n");
    let snap = repo.snapshot("status").unwrap();
    let json = repo.status_json(&snap).unwrap();
    assert!(json.contains("\"resolved\":true"), "{json}");
    repo.commit("resolve", &[]).unwrap();
    let snap = repo.snapshot("status").unwrap();
    let json = repo.status_json(&snap).unwrap();
    assert!(
        json.contains("\"clean\":true,\"conflicted\":false,\"paths\":[],\"conflicts\":[]"),
        "{json}"
    );
}

#[test]
fn ignore_rules_do_not_untrack_files() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap().with_home(root.join("home"));
    write(root, "src.c", b"int x;\n");
    write(root, "build/out.o", b"\0obj");
    write(root, "sub/keep.log", b"keep\n");
    write(root, "sub/junk.log", b"junk\n");
    write(root, ".oxyignore", b"/build\n*.log\n!sub/keep.log\n");
    let snap = repo.snapshot("status").unwrap();
    let added: Vec<&str> = snap.statuses.iter().map(|s| s.path.as_str()).collect();
    assert_eq!(
        added,
        vec![".oxyignore", "src.c", "sub/keep.log"],
        "anchored, glob, and negated rules"
    );
    let h1 = repo.commit("base", &[]).unwrap();
    // Ignoring a tracked file changes nothing about it.
    write(root, ".oxyignore", b"/build\n*.log\n!sub/keep.log\nsrc.c\n");
    let snap = repo.snapshot("status").unwrap();
    assert_eq!(
        snap.statuses
            .iter()
            .map(|s| s.path.as_str())
            .collect::<Vec<_>>(),
        vec![".oxyignore"]
    );
    let h2 = repo.commit("ignore src.c", &[]).unwrap();
    assert!(repo
        .load_state(&[h2])
        .unwrap()
        .materialize()
        .files
        .contains_key("src.c"));
    // Its edits are still seen, by status and by the prompt.
    assert_eq!(repo.quick_dirty().unwrap(), Some(false));
    write(root, "src.c", b"int x, y;\n");
    assert_eq!(repo.quick_dirty().unwrap(), Some(true));
    let snap = repo.snapshot("status").unwrap();
    assert_eq!(
        snap.statuses
            .iter()
            .map(|s| (s.path.as_str(), s.status))
            .collect::<Vec<_>>(),
        vec![("src.c", ChangeStatus::Modified)]
    );
    let h3 = repo.commit("edit src.c", &[]).unwrap();
    assert!(
        matches!(&repo.load_state(&[h3]).unwrap().materialize().files["src.c"].content, FileContent::Text { bytes, .. } if bytes == b"int x, y;\n")
    );
    // Deleting it on disk removes it, ignored or not; a checkout brings it back.
    fs::remove_file(root.join("src.c")).unwrap();
    let snap = repo.snapshot("status").unwrap();
    assert_eq!(
        snap.statuses
            .iter()
            .map(|s| (s.path.as_str(), s.status))
            .collect::<Vec<_>>(),
        vec![("src.c", ChangeStatus::Removed)]
    );
    repo.checkout(&[h3], true, "checkout").unwrap();
    assert_eq!(fs::read(root.join("src.c")).unwrap(), b"int x, y;\n");
    assert!(!repo.snapshot("status").unwrap().changed);
    let _ = h1;
}

#[test]
fn split_works_on_non_heads_by_node() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap().with_home(root.join("home"));
    write(root, "a.txt", b"one\n");
    write(root, "junk/x.lock", b"lock\n");
    let h1 = repo.commit("work plus junk", &[]).unwrap();
    write(root, "a.txt", b"one\ntwo\n");
    let h2 = repo.commit("more work", &[]).unwrap();
    assert_eq!(repo.store().get_change(&h2).unwrap().deps, vec![h1]);
    let id1 = repo.store().get_change(&h1).unwrap().change_id;
    // h1 is not a head: split it by node.
    let (hj, h1b) = repo.split(&h1, &["junk".into()]).unwrap();
    assert_ne!(h1b, h1);
    assert_eq!(
        repo.store().get_change(&h1b).unwrap().change_id,
        id1,
        "the rest keeps the ChangeId"
    );
    let junk = repo.store().get_change(&hj).unwrap();
    assert!(junk.tree_ops.iter().all(
        |op| matches!(op, TreeOp::AddNode { name, .. } if name == "junk" || name == "x.lock")
    ));
    let heads = repo.bookmark_heads().unwrap();
    assert!(
        heads.contains(&hj),
        "the split-off part is a head of its own"
    );
    let snap = repo.load_state(&heads).unwrap().materialize();
    assert!(
        matches!(&snap.files["a.txt"].content, FileContent::Text { bytes, .. } if bytes == b"one\ntwo\n"),
        "the dependent was rewritten onto the new hash"
    );
    assert!(snap.files.contains_key("junk/x.lock"));
    let h2b = heads
        .iter()
        .find(|h| repo.store().get_change(h).unwrap().message == "more work")
        .copied()
        .unwrap();
    assert_eq!(repo.store().get_change(&h2b).unwrap().deps, vec![h1b]);
    assert!(!repo.snapshot("status").unwrap().changed);
    // Abandoning the split-off head removes the junk from history.
    repo.abandon(&hj).unwrap();
    let heads = repo.bookmark_heads().unwrap();
    let snap = repo.load_state(&heads).unwrap().materialize();
    assert!(!snap.files.contains_key("junk/x.lock") && !snap.files.contains_key("junk"));
    assert!(snap.files.contains_key("a.txt"));
    // A dependent that touches the split-off paths blocks the split.
    write(root, "junk/y.lock", b"y\n");
    let hb = repo.commit("junk base", &[]).unwrap();
    write(root, "junk/y.lock", b"yy\n");
    write(root, "b.txt", b"b\n");
    repo.commit("touches junk", &[]).unwrap();
    let err = repo.split(&hb, &["junk".into()]).unwrap_err().to_string();
    assert!(err.contains("depends on the split-off paths"), "{err}");
}

#[test]
fn bookmarks_switch_merge_and_push() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let origin = Repo::init(&root.join("origin")).unwrap();
    let url = root.join("origin").to_string_lossy().to_string();
    let mut repo = Repo::clone(&url, &root.join("r"))
        .unwrap()
        .with_home(root.join("home"));
    let r = root.join("r");
    write(&r, "a.txt", b"a\n");
    let h_a = repo.commit("a", &[]).unwrap();
    assert!(repo.push("origin", false).unwrap()[0].ok);

    // A bookmark at the working copy's base, then work on it.
    assert!(repo.bookmark_create("bad name..", None).is_err());
    assert!(repo.bookmark_create("-x", None).is_err());
    assert_eq!(repo.bookmark_create("feature", None).unwrap(), vec![h_a]);
    assert!(repo.bookmark_create("feature", None).is_err(), "exists");
    repo.bookmark_switch("feature", false).unwrap();
    assert_eq!(repo.config.bookmark, "feature");
    write(&r, "a.txt", b"a\nb\n");
    write(&r, "b.txt", b"b\n");
    let h_b = repo.commit("b on feature", &[]).unwrap();
    assert_eq!(
        repo.bookmark_heads().unwrap(),
        vec![h_b],
        "b edits a.txt, so it depends on a"
    );
    assert_eq!(
        repo.resolve_heads("main").unwrap(),
        vec![h_a],
        "main is untouched"
    );
    assert_eq!(
        repo.resolve_change("feature").unwrap(),
        h_b,
        "a one-head bookmark names its change"
    );
    // Reopening keeps the workspace's bookmark.
    let reopened = Repo::open(&r).unwrap().with_home(root.join("home"));
    assert_eq!(reopened.config.bookmark, "feature");
    // Back to main: b.txt goes away; work there.
    repo.bookmark_switch("main", false).unwrap();
    assert!(!r.join("b.txt").exists());
    assert_eq!(fs::read(r.join("a.txt")).unwrap(), b"a\n");
    write(&r, "c.txt", b"c\n");
    let h_c = repo.commit("c on main", &[]).unwrap();
    let list = repo.bookmarks().unwrap();
    assert_eq!(
        list.iter()
            .map(|b| (b.name.as_str(), b.current))
            .collect::<Vec<_>>(),
        vec![("feature", false), ("main", true)]
    );
    assert_eq!(
        list.iter().find(|b| b.name == "main").unwrap().ahead,
        Some(1),
        "c is not on origin yet"
    );
    // Merge feature into main: the union, both heads, no merge change.
    let m = repo.merge("feature").unwrap();
    assert!(m.changed && m.checked_out);
    let mut want = vec![h_b, h_c];
    want.sort();
    assert_eq!(m.heads, want);
    assert_eq!(fs::read(r.join("b.txt")).unwrap(), b"b\n");
    assert!(!repo.merge("feature").unwrap().changed, "already merged");
    assert!(repo.merge("main").is_err());
    // The other bookmark can be pushed by name and appears at origin.
    assert!(repo.push_bookmark("origin", "feature", false).unwrap()[0].ok);
    assert_eq!(origin.resolve_heads("feature").unwrap(), vec![h_b]);
    assert!(repo.push("origin", false).unwrap()[0].ok);
    assert_eq!(
        repo.bookmarks()
            .unwrap()
            .iter()
            .find(|b| b.name == "main")
            .unwrap()
            .ahead,
        Some(0)
    );
    // A second workspace inherits the current bookmark and can switch independently.
    let ws = repo.workspace_add(&root.join("ws"), None).unwrap();
    assert_eq!(ws.config.bookmark, "main");
    let mut ws = ws;
    ws.bookmark_switch("feature", false).unwrap();
    assert_eq!(
        Repo::open(&r).unwrap().config.bookmark,
        "main",
        "the first workspace is unaffected"
    );
    assert!(
        repo.bookmark_delete("feature").is_err(),
        "current bookmark of another workspace"
    );
    ws.bookmark_switch("main", false).unwrap();
    // Set and delete.
    assert_eq!(repo.bookmark_set("feature", &[h_a]).unwrap(), vec![h_a]);
    assert!(repo.bookmark_delete("main").is_err(), "current here");
    repo.bookmark_delete("feature").unwrap();
    assert!(repo.resolve_heads("feature").is_err());
    assert!(repo.bookmark_set("feature", &[h_a]).is_err());
    assert!(
        repo.checkout(&[h_a], false, "checkout").is_ok(),
        "changes of a deleted bookmark remain"
    );
}

#[test]
fn oxygen_subrepos_pin_follow_and_update() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    // A library repository with two commits, and a bare-ish origin for it.
    let lib_origin = Repo::init(&root.join("lib-origin")).unwrap();
    let lib_url = root.join("lib-origin").to_string_lossy().to_string();
    let lib = Repo::clone(&lib_url, &root.join("lib"))
        .unwrap()
        .with_home(root.join("home"));
    write(&root.join("lib"), "lib.txt", b"v1\n");
    let l1 = lib.commit("lib v1", &[]).unwrap();
    assert!(lib.push("origin", false).unwrap()[0].ok);
    let _ = lib_origin;

    // The application (a clone of its own origin) adds it as a subrepo.
    let app_origin = Repo::init(&root.join("app-origin")).unwrap();
    let app_url = root.join("app-origin").to_string_lossy().to_string();
    let _ = app_origin;
    let app_dir = root.join("app");
    let app = Repo::clone(&app_url, &app_dir)
        .unwrap()
        .with_home(root.join("home"));
    write(&app_dir, "main.txt", b"app\n");
    let pin = app.submodule_add(&lib_url, "libs/lib", None).unwrap();
    assert!(matches!(&pin, crate::subrepo::Pin::Oxy { heads, .. } if heads == &vec![l1]));
    assert!(app_dir.join(".oxymodules").exists() && app_dir.join("libs/lib/.oxy").is_dir());
    let snap = app.snapshot("status").unwrap();
    let paths: Vec<&str> = snap.statuses.iter().map(|s| s.path.as_str()).collect();
    assert_eq!(
        paths,
        vec![".oxymodules", "libs/lib", "main.txt"],
        "the nested files are not walked"
    );
    let a1 = app.commit("app with lib", &[]).unwrap();
    let files = app.load_state(&[a1]).unwrap().materialize().files;
    assert_eq!(files["libs/lib"].kind, NodeKind::Subrepo);
    assert!(!files.contains_key("libs/lib/lib.txt"));
    assert!(!app.snapshot("status").unwrap().changed);
    let subs = app.subrepos().unwrap();
    assert_eq!(subs.len(), 1);
    assert_eq!(subs[0].actual.as_ref(), Some(&subs[0].pin));

    // Advance the nested repository: the parent sees a modified pin.
    let nested = Repo::open(&app_dir.join("libs/lib"))
        .unwrap()
        .with_home(root.join("home"));
    write(&app_dir.join("libs/lib"), "lib.txt", b"v2\n");
    let l2 = nested.commit("lib v2", &[]).unwrap();
    assert!(nested.push("origin", false).unwrap()[0].ok);
    let snap = app.snapshot("status").unwrap();
    assert_eq!(
        snap.statuses
            .iter()
            .map(|s| (s.path.as_str(), s.status))
            .collect::<Vec<_>>(),
        vec![("libs/lib", ChangeStatus::Modified)]
    );
    let a2 = app.commit("bump lib", &[]).unwrap();
    // Checking out the older app state moves the nested repository back.
    let r = app.checkout(&[a1], false, "checkout").unwrap();
    assert!(r.notes.is_empty(), "{:?}", r.notes);
    assert_eq!(fs::read(app_dir.join("libs/lib/lib.txt")).unwrap(), b"v1\n");
    assert_eq!(
        Repo::open(&app_dir.join("libs/lib"))
            .unwrap()
            .bookmark_heads()
            .unwrap(),
        vec![l1]
    );
    assert!(!app.snapshot("status").unwrap().changed);
    // A dirty nested repository is left alone and reported.
    write(&app_dir.join("libs/lib"), "scratch.txt", b"wip\n");
    let r = app.checkout(&[a2], false, "checkout").unwrap();
    assert!(
        r.notes.iter().any(|n| n.contains("uncommitted")),
        "{:?}",
        r.notes
    );
    assert_eq!(fs::read(app_dir.join("libs/lib/lib.txt")).unwrap(), b"v1\n");
    fs::remove_file(app_dir.join("libs/lib/scratch.txt")).unwrap();
    let r = app.submodule_update(false, &[]).unwrap();
    assert_eq!(r, vec![("libs/lib".to_string(), SubrepoSync::Updated)]);
    assert_eq!(fs::read(app_dir.join("libs/lib/lib.txt")).unwrap(), b"v2\n");
    let _ = l2;

    // A fresh clone of the app has the pin but no nested repository until update --init.
    assert!(app.push("origin", false).unwrap()[0].ok);
    let clone_dir = root.join("app-clone");
    let clone = Repo::clone(&app_url, &clone_dir)
        .unwrap()
        .with_home(root.join("home"));
    assert!(!clone_dir.join("libs/lib/.oxy").exists());
    assert_eq!(
        clone.submodule_update(false, &[]).unwrap(),
        vec![("libs/lib".to_string(), SubrepoSync::Missing)]
    );
    assert_eq!(
        clone.submodule_update(true, &[]).unwrap(),
        vec![("libs/lib".to_string(), SubrepoSync::Updated)]
    );
    assert_eq!(
        fs::read(clone_dir.join("libs/lib/lib.txt")).unwrap(),
        b"v2\n"
    );
    assert!(!clone.snapshot("status").unwrap().changed);
    // Removing the subrepo leaves the directory and drops the node.
    clone.submodule_remove("libs/lib").unwrap();
    let snap = clone.snapshot("status").unwrap();
    assert!(
        snap.statuses
            .iter()
            .any(|s| s.path == "libs/lib" && s.status == ChangeStatus::Removed),
        "{:?}",
        snap.statuses
    );
    let c = clone.commit("drop lib", &[]).unwrap();
    assert!(!clone
        .load_state(&[c])
        .unwrap()
        .materialize()
        .files
        .contains_key("libs/lib"));
    assert!(clone_dir.join("libs/lib/lib.txt").exists());
    assert!(
        !clone.snapshot("status").unwrap().changed,
        "an unregistered nested repository is ignored"
    );
}

#[test]
fn git_submodules_import_and_export_as_gitlinks() {
    hermetic();
    if std::process::Command::new("git")
        .arg("--version")
        .output()
        .is_err()
    {
        eprintln!("git not installed; skipping");
        return;
    }
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let git_in = |d: &Path, args: &[&str]| -> String {
        let out = std::process::Command::new("git")
            .arg("-C")
            .arg(d)
            .args([
                "-c",
                "user.name=Grace",
                "-c",
                "[email protected]",
                "-c",
                "commit.gpgsign=false",
                "-c",
                "protocol.file.allow=always",
            ])
            .args(args)
            .output()
            .unwrap();
        assert!(
            out.status.success(),
            "git {args:?}: {}",
            String::from_utf8_lossy(&out.stderr)
        );
        String::from_utf8_lossy(&out.stdout).trim().to_string()
    };
    let sub = root.join("sub");
    fs::create_dir_all(&sub).unwrap();
    git_in(&sub, &["init", "-q", "-b", "main"]);
    write(&sub, "s.txt", b"sub\n");
    git_in(&sub, &["add", "."]);
    git_in(&sub, &["commit", "-q", "-m", "sub initial"]);
    let sub_sha = git_in(&sub, &["rev-parse", "HEAD"]);
    let g = root.join("main.git");
    fs::create_dir_all(&g).unwrap();
    git_in(&g, &["init", "-q", "-b", "main"]);
    write(&g, "README.md", b"# app\n");
    git_in(&g, &["add", "."]);
    git_in(&g, &["commit", "-q", "-m", "initial"]);
    git_in(
        &g,
        &[
            "submodule",
            "add",
            "-q",
            sub.to_str().unwrap(),
            "vendor/sub",
        ],
    );
    git_in(&g, &["commit", "-q", "-m", "add submodule"]);

    let dest = root.join("oxy");
    let repo = Repo::init(&dest).unwrap().with_home(root.join("home"));
    let rep = repo.import_git(&g, "main").unwrap();
    assert_eq!((rep.commits, rep.submodules), (2, 1));
    let files = repo
        .load_state(&repo.bookmark_heads().unwrap())
        .unwrap()
        .materialize()
        .files;
    assert_eq!(files["vendor/sub"].kind, NodeKind::Subrepo);
    let FileContent::Opaque { blobs } = &files["vendor/sub"].content else {
        panic!()
    };
    assert_eq!(
        crate::subrepo::Pin::decode(&repo.read_blob(&blobs[0]).unwrap()).unwrap(),
        crate::subrepo::Pin::Git {
            sha: sub_sha.clone(),
            branch: "HEAD".into()
        }
    );
    let modules =
        crate::subrepo::Modules::parse(&fs::read_to_string(dest.join(".oxymodules")).unwrap());
    assert_eq!(modules.entries["vendor/sub"].url, sub.to_string_lossy());
    assert!(modules.entries["vendor/sub"].git);
    assert!(
        files.contains_key(".gitmodules"),
        "the Git file is kept for round trips"
    );
    assert!(
        !dest.join("vendor/sub/.git").exists(),
        "not cloned until update --init"
    );
    assert!(!repo.snapshot("status").unwrap().changed);
    // update --init clones it at the pinned commit; status is unchanged.
    assert_eq!(
        repo.submodule_update(true, &[]).unwrap(),
        vec![("vendor/sub".to_string(), SubrepoSync::Updated)]
    );
    assert_eq!(
        git_in(&dest.join("vendor/sub"), &["rev-parse", "HEAD"]),
        sub_sha
    );
    assert!(!repo.snapshot("status").unwrap().changed);
    // Export writes the gitlink and .gitmodules back.
    let mirror = root.join("mirror.git");
    let rep = repo.git_export(&mirror).unwrap();
    assert_eq!(rep.skipped_subrepos, 0);
    let ls = git_in(&mirror, &["ls-tree", "main", "vendor/sub"]);
    assert!(
        ls.starts_with("160000 commit ") && ls.contains(&sub_sha),
        "{ls}"
    );
    assert_eq!(
        git_in(&mirror, &["ls-tree", "--name-only", "main"]),
        ".gitmodules\nREADME.md\nvendor"
    );
    let orig_tree = git_in(&g, &["rev-parse", "main^{tree}"]);
    assert_eq!(
        git_in(&mirror, &["rev-parse", "main^{tree}"]),
        orig_tree,
        "tree round trip"
    );
}

#[test]
fn partial_commits_by_path_and_by_hunk() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap().with_home(root.join("home"));
    write(root, "a.txt", b"1\n2\n3\n");
    write(root, "b.txt", b"b\n");
    let h0 = repo.commit("base", &[]).unwrap();
    write(root, "a.txt", b"0\n1\n2\n3\n4\n");
    write(root, "b.txt", b"b\nbb\n");
    write(root, "c.txt", b"c\n");
    // By path: only a.txt goes in; the rest stays on disk as uncommitted work.
    let h1 = repo
        .commit_selection("a only", &[], &Selection::Paths(vec!["a.txt".into()]))
        .unwrap();
    let c1 = repo.store().get_change(&h1).unwrap();
    assert!(
        c1.tree_ops.is_empty() && c1.edits.iter().all(|e| e.node() == c1.edits[0].node()),
        "{:?}",
        c1.tree_ops
    );
    assert_eq!(c1.deps, vec![h0]);
    let files = repo.load_state(&[h1]).unwrap().materialize().files;
    assert!(
        matches!(&files["a.txt"].content, FileContent::Text { bytes, .. } if bytes == b"0\n1\n2\n3\n4\n")
    );
    assert!(matches!(&files["b.txt"].content, FileContent::Text { bytes, .. } if bytes == b"b\n"));
    assert!(!files.contains_key("c.txt"));
    let snap = repo.snapshot("status").unwrap();
    assert_eq!(
        snap.statuses
            .iter()
            .map(|s| (s.path.as_str(), s.status))
            .collect::<Vec<_>>(),
        vec![
            ("b.txt", ChangeStatus::Modified),
            ("c.txt", ChangeStatus::Added)
        ]
    );
    assert_eq!(
        fs::read(root.join("b.txt")).unwrap(),
        b"b\nbb\n",
        "disk untouched"
    );
    // By hunk: pick the b.txt insert; c.txt's addition is left.
    let (_, hunks) = repo.hunks().unwrap();
    let b_hunk = hunks
        .iter()
        .find(|h| h.path == "b.txt" && h.text.contains("+bb"))
        .unwrap()
        .index;
    let h2 = repo
        .commit_selection("b only", &[], &Selection::Hunks(vec![b_hunk]))
        .unwrap();
    let files = repo.load_state(&[h2]).unwrap().materialize().files;
    assert!(
        matches!(&files["b.txt"].content, FileContent::Text { bytes, .. } if bytes == b"b\nbb\n")
    );
    assert!(!files.contains_key("c.txt"));
    let snap = repo.snapshot("status").unwrap();
    assert_eq!(
        snap.statuses
            .iter()
            .map(|s| s.path.as_str())
            .collect::<Vec<_>>(),
        vec!["c.txt"]
    );
    // Choosing only the content hunk of a file in a new directory pulls in
    // the directory and file additions it needs.
    write(root, "d/e.txt", b"e\n");
    let (_, hunks) = repo.hunks().unwrap();
    let e_insert = hunks
        .iter()
        .find(|h| h.path == "d/e.txt" && h.text.contains("+e"))
        .unwrap()
        .index;
    let h3 = repo
        .commit_selection("e only", &[], &Selection::Hunks(vec![e_insert]))
        .unwrap();
    let c3 = repo.store().get_change(&h3).unwrap();
    assert_eq!(c3.tree_ops.len(), 2, "{:?}", c3.tree_ops);
    let files = repo.load_state(&[h3]).unwrap().materialize().files;
    assert!(files.contains_key("d/e.txt") && !files.contains_key("c.txt"));
    // Choosing a new file's addition hunk brings its content along.
    write(root, "f/g.txt", b"g\n");
    let (_, hunks) = repo.hunks().unwrap();
    let g_add = hunks
        .iter()
        .find(|h| h.path == "f/g.txt" && h.text.starts_with("A "))
        .unwrap()
        .index;
    let h4 = repo
        .commit_selection("g by addition", &[], &Selection::Hunks(vec![g_add]))
        .unwrap();
    let files = repo.load_state(&[h4]).unwrap().materialize().files;
    assert!(
        matches!(&files["f/g.txt"].content, FileContent::Text { bytes, .. } if bytes == b"g\n")
    );
    assert!(!repo
        .snapshot("status")
        .unwrap()
        .statuses
        .iter()
        .any(|s| s.path == "f/g.txt"));
    // Everything left commits normally; the working copy is then clean.
    repo.commit("the rest", &[]).unwrap();
    assert!(!repo.snapshot("status").unwrap().changed);
    let files = repo
        .load_state(&repo.bookmark_heads().unwrap())
        .unwrap()
        .materialize()
        .files;
    assert!(files.contains_key("c.txt"));
}

#[test]
fn blame_attributes_lines_to_introducing_changes_across_renames() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let mut repo = Repo::init(root).unwrap().with_home(root.join("home"));
    repo.create_identity("Ada", "[email protected]", IdentityScope::User)
        .unwrap();
    write(root, "a.txt", b"one\n");
    let h1 = repo.commit("first", &[]).unwrap();
    write(root, "a.txt", b"one\ntwo\n");
    let h2 = repo.commit("second", &[]).unwrap();
    let b = repo.blame("a.txt").unwrap();
    assert_eq!(
        b.iter()
            .map(|l| (l.line, l.hash, l.text.as_slice()))
            .collect::<Vec<_>>(),
        vec![(1, h1, b"one\n".as_slice()), (2, h2, b"two\n".as_slice())]
    );
    assert!(b.iter().all(|l| l.author == "Ada"));
    assert_eq!(
        b[0].change_id,
        repo.store().get_change(&h1).unwrap().change_id
    );
    fs::rename(root.join("a.txt"), root.join("b.txt")).unwrap();
    repo.commit("rename", &[]).unwrap();
    let b = repo.blame("b.txt").unwrap();
    assert_eq!(
        b.iter().map(|l| l.hash).collect::<Vec<_>>(),
        vec![h1, h2],
        "the node survives the rename"
    );
    assert!(repo.blame("a.txt").is_err());
}

#[test]
fn bisect_finds_the_first_bad_change() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap().with_home(root.join("home"));
    let mut content = String::new();
    let mut hashes = Vec::new();
    for i in 1..=8 {
        content.push_str(&format!("line {i}{}\n", if i == 5 { " bug" } else { "" }));
        write(root, "f.txt", content.as_bytes());
        hashes.push(repo.commit(&format!("step {i}"), &[]).unwrap());
    }
    // Each step appends after the previous line, so the chain is linear.
    assert_eq!(repo.bookmark_heads().unwrap(), vec![hashes[7]]);
    repo.bisect_start().unwrap();
    assert!(matches!(
        repo.bisect_mark(Some(true), &[hashes[0]]).unwrap(),
        BisectStep::NeedMarks { good: 1, bad: 0 }
    ));
    let step = repo.bisect_mark(Some(false), &[hashes[7]]).unwrap();
    assert!(
        matches!(step, BisectStep::Testing { remaining: 7, .. }),
        "{step:?}"
    );
    // Automated: bad when the bug line is present.
    let step = repo
        .bisect_run(&["sh".into(), "-c".into(), "! grep -q bug f.txt".into()])
        .unwrap();
    assert_eq!(step, BisectStep::Found { culprit: hashes[4] });
    assert_eq!(
        repo.bisect_status().unwrap(),
        Some(BisectStep::Found { culprit: hashes[4] })
    );
    repo.bisect_reset().unwrap();
    assert_eq!(fs::read_to_string(root.join("f.txt")).unwrap(), content);
    assert!(repo.bisect_status().unwrap().is_none());
    assert!(!repo.snapshot("status").unwrap().changed);
    // Manual marks and a skip.
    repo.bisect_start().unwrap();
    repo.bisect_mark(Some(true), &[hashes[0]]).unwrap();
    let mut step = repo.bisect_mark(Some(false), &[hashes[7]]).unwrap();
    let mut skipped_once = false;
    let mut guard = 0;
    while let BisectStep::Testing { .. } = step {
        guard += 1;
        assert!(guard < 20);
        let text = fs::read_to_string(root.join("f.txt")).unwrap();
        if !skipped_once && text.contains("line 6") {
            // An untestable state away from the boundary: the search routes around it.
            skipped_once = true;
            step = repo.bisect_mark(None, &[]).unwrap();
            continue;
        }
        step = repo.bisect_mark(Some(!text.contains("bug")), &[]).unwrap();
    }
    assert!(skipped_once);
    assert_eq!(step, BisectStep::Found { culprit: hashes[4] });
    repo.bisect_reset().unwrap();
    // Skipping the culprit itself leaves it among the candidates reported.
    repo.bisect_start().unwrap();
    repo.bisect_mark(Some(true), &[hashes[0]]).unwrap();
    let mut step = repo.bisect_mark(Some(false), &[hashes[7]]).unwrap();
    let mut guard = 0;
    while let BisectStep::Testing { heads, .. } = &step {
        guard += 1;
        assert!(guard < 20);
        let text = fs::read_to_string(root.join("f.txt")).unwrap();
        let is_culprit_state =
            heads.contains(&hashes[4]) && !heads.iter().any(|h| hashes[5..].contains(h));
        step = if is_culprit_state {
            repo.bisect_mark(None, &[]).unwrap()
        } else {
            repo.bisect_mark(Some(!text.contains("bug")), &[]).unwrap()
        };
    }
    match step {
        BisectStep::Inconclusive { candidates } => assert!(
            candidates.contains(&hashes[4]) && candidates.len() <= 2,
            "{candidates:?}"
        ),
        other => panic!("{other:?}"),
    }
    repo.bisect_reset().unwrap();
}

#[test]
fn squash_folds_a_change_into_its_dependency() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap().with_home(root.join("home"));
    write(root, "a.txt", b"1\n");
    let a = repo.commit("A", &[]).unwrap();
    write(root, "a.txt", b"1\n2\n");
    let c = repo.commit("C", &[]).unwrap();
    write(root, "a.txt", b"1\n2\n3\n");
    let e = repo.commit("E", &[]).unwrap();
    write(root, "b.txt", b"b\n");
    let b = repo.commit("B", &[]).unwrap();
    let id_a = repo.store().get_change(&a).unwrap().change_id;
    let id_e = repo.store().get_change(&e).unwrap().change_id;
    // E depends on C which A lacks: refused, naming it.
    let err = repo.squash(&e, &a).unwrap_err().to_string();
    assert!(err.contains(&c.short(12)), "{err}");
    // C into A: A' has both, C is gone, E follows and still reads the same.
    let a2 = repo.squash(&c, &a).unwrap();
    let a2c = repo.store().get_change(&a2).unwrap();
    assert_eq!(a2c.change_id, id_a);
    assert!(a2c.deps.is_empty());
    let heads = repo.bookmark_heads().unwrap();
    let st = repo.load_state(&heads).unwrap();
    assert!(!st.contains(&c) && !st.contains(&a) && !st.contains(&e));
    let e2 = st
        .changes()
        .find(|(_, m)| m.change_id == id_e)
        .map(|(h, _)| *h)
        .unwrap();
    assert_eq!(
        repo.store().get_change(&e2).unwrap().deps,
        vec![a2],
        "E now depends on A' alone"
    );
    let files = st.materialize().files;
    assert!(
        matches!(&files["a.txt"].content, FileContent::Text { bytes, .. } if bytes == b"1\n2\n3\n")
    );
    assert!(files.contains_key("b.txt"));
    assert!(st.contains(&b));
    assert!(!repo.snapshot("status").unwrap().changed);
    assert_eq!(repo.log().unwrap().len(), 4, "working copy, B, E', A'");
    // Undo restores the three original changes.
    repo.undo().unwrap();
    repo.undo().unwrap();
    let st = repo.load_state(&repo.bookmark_heads().unwrap()).unwrap();
    assert!(st.contains(&c) && st.contains(&a) && st.contains(&e));
}

#[test]
fn rebase_re_expresses_a_change_against_another_base() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap().with_home(root.join("home"));
    write(root, "a.txt", b"1\n2\n");
    let a = repo.commit("A", &[]).unwrap();
    write(root, "a.txt", b"1\n2\n3\n");
    let c = repo.commit("C: append 3", &[]).unwrap();
    write(root, "a.txt", b"1\n2\n3\n4\n");
    let e = repo.commit("E: append 4", &[]).unwrap();
    // A different base: A plus a change that prepends a line.
    repo.checkout(&[a], true, "checkout").unwrap();
    write(root, "a.txt", b"0\n1\n2\n");
    let d = repo.commit("D: prepend 0", &[]).unwrap();
    let id_c = repo.store().get_change(&c).unwrap().change_id;
    let id_e = repo.store().get_change(&e).unwrap().change_id;
    // Rebase C onto D: its effect (append 3) re-derived against D's text.
    let c2 = repo.rebase(&c, &[d]).unwrap();
    let c2c = repo.store().get_change(&c2).unwrap();
    assert_eq!(c2c.change_id, id_c);
    assert!(c2c.deps.contains(&d), "{:?}", c2c.deps);
    let heads = repo.bookmark_heads().unwrap();
    let st = repo.load_state(&heads).unwrap();
    assert!(!st.contains(&c) && st.contains(&d));
    let e2 = st
        .changes()
        .find(|(_, m)| m.change_id == id_e)
        .map(|(h, _)| *h)
        .unwrap();
    let e2deps = repo.store().get_change(&e2).unwrap().deps;
    assert!(
        e2deps.contains(&c2) && !e2deps.contains(&c) && e2deps.contains(&a),
        "E follows C by content and still depends on A, which introduced the file: {e2deps:?}"
    );
    let files = st.materialize().files;
    assert!(
        matches!(&files["a.txt"].content, FileContent::Text { bytes, .. } if bytes == b"0\n1\n2\n3\n4\n"),
        "{:?}",
        files["a.txt"].content
    );
    assert!(!files["a.txt"].is_conflicted());
    // Rebasing onto a state that already contains the change is refused.
    assert!(repo.rebase(&c2, &[c2]).is_err());
    let err = repo.rebase(&e2, &[d]).unwrap_err().to_string();
    assert!(
        err.contains("lacks dependencies"),
        "E needs C, which D's state does not have: {err}"
    );
}

#[test]
fn unsigned_tags_keep_their_message() {
    hermetic();
    let dir = tempfile::tempdir().unwrap();
    let root = dir.path();
    let repo = Repo::init(root).unwrap().with_home(root.join("home"));
    write(root, "a.txt", b"a\n");
    repo.commit("a", &[]).unwrap();
    assert!(repo.secret_key().unwrap().is_none());
    repo.tag_create("v1", &repo.bookmark_heads().unwrap(), "first release")
        .unwrap();
    let tags = repo.tags().unwrap();
    assert_eq!(
        (
            tags[0].name.as_str(),
            tags[0].message.as_str(),
            tags[0].signer.as_deref()
        ),
        ("v1", "first release", None)
    );
    assert!(
        repo.tag_refs().unwrap()[0].attestation.is_none(),
        "an unsigned attestation is not advertised"
    );
}
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