OXYGENHUB
# d82e44097323 oxygen / crates / oxy-core / src / repo / sync.rs
54.0 KiB · Rust · last changed Proposal clients: oxy seal --proposal, oxy proposal show|land, seal-only pushes, http_get for hub APIs 1 month ago source blame history raw
1 
//! Serving and talking to remotes (spec §10.2, §16).
2
3 
use super::*;
4
5 
/// What a fetch brought in.
6 
#[derive(Debug, Clone, PartialEq, Eq, Default)]
7 
pub struct FetchReport {
8 
    /// Bookmark name, its heads, and how many changes were new.
9 
    pub refs: Vec<(String, Vec<ChangeHash>, usize)>,
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    /// Tags adopted from the remote.
11 
    pub new_tags: usize,
12 
    /// The remote has never presented a policy, so nothing was verified
13 
    /// against one (spec §14.5: warn loudly).
14 
    pub unverified: bool,
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}
16
17 
#[derive(Debug, Clone, PartialEq, Eq)]
18 
pub struct PullReport {
19 
    pub heads: Vec<ChangeHash>,
20 
    pub changed: bool,
21 
    pub checked_out: bool,
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}
23
24 
impl Repo {
25 
    // ------------------------------------------------------------ serving (spec §16)
26
27 
    fn ref_attest_path(&self, bookmark: &str) -> PathBuf {
28 
        self.oxy.join("attest").join(bookmark)
29 
    }
30
31 
    /// The latest reference attestation stored for a bookmark.
32 
    pub fn latest_ref_attest(&self, bookmark: &str) -> Result<Option<(ObjectRef, SignedAttest)>> {
33 
        match fs::read_to_string(self.ref_attest_path(bookmark)) {
34 
            Ok(h) => {
35 
                let r = ObjectRef::from_hex(h.trim())
36 
                    .ok_or_else(|| RepoError::Msg("corrupt attestation pointer".into()))?;
37 
                Ok(Some((
38 
                    r,
39 
                    SignedAttest {
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                        attest: self.store.get_attest(&r)?,
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                        sigs: self.store.signatures(&r)?,
42 
                    },
43 
                )))
44 
            }
45 
            Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(None),
46 
            Err(e) => Err(e.into()),
47 
        }
48 
    }
49
50 
    fn set_ref_attest(&self, bookmark: &str, r: &ObjectRef) -> Result<()> {
51 
        fs::create_dir_all(self.oxy.join("attest"))?;
52 
        write_atomic(&self.ref_attest_path(bookmark), r.to_hex().as_bytes())
53 
    }
54
55 
    pub fn remote_refs(&self) -> Result<RefsResponse> {
56 
        let view = self.view()?;
57 
        let mut out = Vec::new();
58 
        for (name, state) in &view.bookmarks {
59 
            let latest = self.latest_ref_attest(name)?.map(|(_, a)| a);
60 
            let last_serial = latest.as_ref().and_then(|a| match a.attest.body {
61 
                AttestBody::Ref { serial, .. } => Some(serial),
62 
                _ => None,
63 
            });
64 
            let attestation = latest.filter(|a| matches!(&a.attest.body, AttestBody::Ref { new_state, .. } if new_state == state));
65 
            out.push(RemoteRef {
66 
                name: name.clone(),
67 
                state: *state,
68 
                heads: self.store.get_state(state)?.heads,
69 
                attestation,
70 
                last_serial,
71 
            });
72 
        }
73 
        let policy = self.current_policy()?.map(|(_, sp)| sp);
74 
        let history = self
75 
            .policy_history()?
76 
            .into_iter()
77 
            .filter(|sp| {
78 
                policy
79 
                    .as_ref()
80 
                    .is_some_and(|p| sp.policy.serial < p.policy.serial)
81 
            })
82 
            .collect();
83 
        Ok(RefsResponse {
84 
            refs: out,
85 
            policy,
86 
            tags: self.tag_refs()?,
87 
            history,
88 
        })
89 
    }
90
91 
    /// Every change reachable from `heads` that is in the store.
92 
    fn closure_in_store(&self, heads: &[ChangeHash]) -> Result<BTreeSet<ChangeHash>> {
93 
        let mut seen = BTreeSet::new();
94 
        let mut stack: Vec<ChangeHash> = heads.to_vec();
95 
        while let Some(h) = stack.pop() {
96 
            if seen.contains(&h) || !self.store.has(&h) {
97 
                continue;
98 
            }
99 
            seen.insert(h);
100 
            stack.extend(self.store.get_change(&h)?.deps);
101 
        }
102 
        Ok(seen)
103 
    }
104
105 
    /// The changes within `depth` dependency steps of `heads` (spec §17),
106 
    /// nearest first; depth 1 is the heads themselves.
107 
    pub fn shallow_changes(&self, heads: &[ChangeHash], depth: u32) -> Result<Vec<ChangeHash>> {
108 
        let mut out = Vec::new();
109 
        let mut seen: BTreeSet<ChangeHash> = BTreeSet::new();
110 
        let mut layer: Vec<ChangeHash> = heads.to_vec();
111 
        for _ in 0..depth.max(1) {
112 
            let mut next = Vec::new();
113 
            for h in layer {
114 
                if !seen.insert(h) || !self.store.has(&h) {
115 
                    continue;
116 
                }
117 
                let c = self.store.get_change(&h)?;
118 
                next.extend(c.deps.iter().copied());
119 
                out.push(h);
120 
            }
121 
            if next.is_empty() {
122 
                break;
123 
            }
124 
            layer = next;
125 
        }
126 
        out.reverse();
127 
        Ok(out)
128 
    }
129
130 
    fn shallow_path(&self) -> PathBuf {
131 
        self.oxy.join("shallow")
132 
    }
133
134 
    /// The shallow boundary: dependencies this repository does not hold (spec §17).
135 
    pub fn boundary(&self) -> BTreeSet<ChangeHash> {
136 
        fs::read_to_string(self.shallow_path())
137 
            .map(|t| t.lines().filter_map(ObjectRef::from_hex).collect())
138 
            .unwrap_or_default()
139 
    }
140
141 
    pub fn is_shallow(&self) -> bool {
142 
        !self.boundary().is_empty()
143 
    }
144
145 
    fn write_boundary(&self, boundary: &BTreeSet<ChangeHash>) -> Result<()> {
146 
        if boundary.is_empty() {
147 
            let _ = fs::remove_file(self.shallow_path());
148 
            return Ok(());
149 
        }
150 
        let text: String = boundary
151 
            .iter()
152 
            .map(|h| format!("{}\n", h.to_hex()))
153 
            .collect();
154 
        write_atomic(&self.shallow_path(), text.as_bytes())
155 
    }
156
157 
    /// Recompute the boundary from what is stored: every dependency of a
158 
    /// stored change that is not itself stored.
159 
    fn refresh_boundary(&self, imported: &[ChangeHash]) -> Result<()> {
160 
        let mut boundary = self.boundary();
161 
        boundary.retain(|h| !self.store.has(h));
162 
        for h in imported {
163 
            for d in self.store.get_change(h)?.deps {
164 
                if !self.store.has(&d) {
165 
                    boundary.insert(d);
166 
                }
167 
            }
168 
        }
169 
        self.write_boundary(&boundary)
170 
    }
171
172 
    /// Fetch `depth` more levels of history below the shallow boundary.
173 
    pub fn deepen(&self, remote_name: &str, depth: u32) -> Result<usize> {
174 
        let boundary = self.boundary();
175 
        if boundary.is_empty() {
176 
            return Ok(0);
177 
        }
178 
        let remote = self.open_named_remote(remote_name)?;
179 
        let wanted = remote.shallow(&boundary.iter().copied().collect::<Vec<_>>(), depth)?;
180 
        let bundle = remote.fetch(&wanted, self.config.max_blob)?;
181 
        let imported = self.import_bundle_shallow(&bundle, false)?;
182 
        if self.config.max_blob.is_some() {
183 
            self.register_missing_blobs(&imported, remote_name)?;
184 
        }
185 
        self.refresh_boundary(&imported)?;
186 
        Ok(imported.len())
187 
    }
188
189 
    /// `closure(want) \ closure(have)`, dependencies first (spec §16.2).
190 
    pub fn negotiate(&self, have: &[ChangeHash], want: &[ChangeHash]) -> Result<Vec<ChangeHash>> {
191 
        let have = self.closure_in_store(have)?;
192 
        // In a shallow repository the walk stops at the boundary, whose
193 
        // changes the remote is assumed to hold.
194 
        let boundary = self.boundary();
195 
        let mut out = Vec::new();
196 
        let mut done: BTreeSet<ChangeHash> = have.clone();
197 
        done.extend(boundary.iter().copied());
198 
        // Iterative post-order DFS.
199 
        let mut stack: Vec<(ChangeHash, bool)> = want.iter().rev().map(|h| (*h, false)).collect();
200 
        while let Some((h, expanded)) = stack.pop() {
201 
            if done.contains(&h) {
202 
                continue;
203 
            }
204 
            if !self.store.has(&h) {
205 
                return fail(format!("change {} is not in this repository", h.short(12)));
206 
            }
207 
            if expanded {
208 
                done.insert(h);
209 
                out.push(h);
210 
                continue;
211 
            }
212 
            stack.push((h, true));
213 
            for d in self.store.get_change(&h)?.deps {
214 
                if !done.contains(&d) {
215 
                    stack.push((d, false));
216 
                }
217 
            }
218 
        }
219 
        Ok(out)
220 
    }
221
222 
    /// Bundle changes (in the given dependency order) with their signatures,
223 
    /// seals, identities, blobs, chunks.
224 
    pub fn bundle_for(&self, changes: &[ChangeHash]) -> Result<Bundle> {
225 
        self.bundle_for_filtered(changes, None)
226 
    }
227
228 
    /// Objects by reference for the `objects` endpoint; a blob brings its chunks.
229 
    pub fn objects_for(&self, refs: &[ObjectRef]) -> Result<Vec<(ObjectType, Vec<u8>)>> {
230 
        let mut out = Vec::new();
231 
        for r in refs {
232 
            let (ty, body) = match self.store.get(r) {
233 
                Ok(x) => x,
234 
                Err(StoreError::NotFound(_)) => continue,
235 
                Err(e) => return Err(e.into()),
236 
            };
237 
            if ty == ObjectType::Blob {
238 
                for c in Blob::decode(&body)?.chunks {
239 
                    if let Ok((cty, cb)) = self.store.get(&c) {
240 
                        out.push((cty, cb));
241 
                    }
242 
                }
243 
            }
244 
            out.push((ty, body));
245 
        }
246 
        Ok(out)
247 
    }
248
249 
    /// Like `bundle_for`, leaving out blobs larger than `max_blob` bytes
250 
    /// (and their chunks) so the receiver fetches them lazily (spec §13.5).
251 
    pub fn bundle_for_filtered(
252 
        &self,
253 
        changes: &[ChangeHash],
254 
        max_blob: Option<u64>,
255 
    ) -> Result<Bundle> {
256 
        let mut bundle = Bundle::default();
257 
        let mut objects: BTreeSet<ObjectRef> = BTreeSet::new();
258 
        let mut seals: BTreeSet<ObjectRef> = BTreeSet::new();
259 
        let add_object = |r: &ObjectRef, objects: &mut BTreeSet<ObjectRef>| {
260 
            if !r.is_zero() && self.store.has(r) {
261 
                objects.insert(*r);
262 
            }
263 
        };
264 
        for h in changes {
265 
            let c = self.store.get_change(h)?;
266 
            let sigs = self.store.signatures(h)?;
267 
            add_object(&c.author, &mut objects);
268 
            for s in &sigs {
269 
                add_object(&s.key, &mut objects);
270 
            }
271 
            for e in &c.edits {
272 
                if let Edit::Replace { old, new, .. } = e {
273 
                    for b in [old, new].into_iter().flatten() {
274 
                        if self.store.has(b) {
275 
                            if let Ok(blob) =
276 
                                Blob::decode(&self.store.get_typed(b, ObjectType::Blob)?)
277 
                            {
278 
                                if max_blob.is_some_and(|m| blob.length > m) {
279 
                                    continue;
280 
                                }
281 
                                objects.insert(*b);
282 
                                objects.extend(blob.chunks.iter().copied());
283 
                            }
284 
                        }
285 
                    }
286 
                }
287 
            }
288 
            for s in self.store.seals_for(h)? {
289 
                seals.insert(s);
290 
            }
291 
            bundle.changes.push((c, sigs));
292 
        }
293 
        for r in seals {
294 
            let attest = self.store.get_attest(&r)?;
295 
            let sigs = self.store.signatures(&r)?;
296 
            for s in &sigs {
297 
                add_object(&s.key, &mut objects);
298 
            }
299 
            bundle.attests.push(SignedAttest { attest, sigs });
300 
        }
301 
        for r in objects {
302 
            let (ty, body) = self.store.get(&r)?;
303 
            bundle.objects.push((ty, body));
304 
        }
305 
        Ok(bundle)
306 
    }
307
308 
    /// Store a bundle's contents. With `strict`, every change must
309 
    /// authenticate (signature or seal by its author or a delegate).
310 
    pub fn import_bundle(&self, bundle: &Bundle, strict: bool) -> Result<Vec<ChangeHash>> {
311 
        self.import_bundle_inner(bundle, strict, false)
312 
    }
313
314 
    /// Like `import_bundle`, accepting changes whose dependencies are absent
315 
    /// (they join the shallow boundary).
316 
    pub fn import_bundle_shallow(&self, bundle: &Bundle, strict: bool) -> Result<Vec<ChangeHash>> {
317 
        self.import_bundle_inner(bundle, strict, true)
318 
    }
319
320 
    fn import_bundle_inner(
321 
        &self,
322 
        bundle: &Bundle,
323 
        strict: bool,
324 
        shallow: bool,
325 
    ) -> Result<Vec<ChangeHash>> {
326 
        let batch = self.store.begin_batch()?;
327 
        let result = self.import_bundle_batched(bundle, strict, shallow);
328 
        batch.finish()?;
329 
        result
330 
    }
331
332 
    fn import_bundle_batched(
333 
        &self,
334 
        bundle: &Bundle,
335 
        strict: bool,
336 
        shallow: bool,
337 
    ) -> Result<Vec<ChangeHash>> {
338 
        for (ty, body) in &bundle.objects {
339 
            match ty {
340 
                ObjectType::Chunk
341 
                | ObjectType::Blob
342 
                | ObjectType::Identity
343 
                | ObjectType::State
344 
                | ObjectType::Checkpoint => {
345 
                    self.store.put(*ty, body)?;
346 
                }
347 
                other => return fail(format!("bundle may not carry {} objects", other.name())),
348 
            }
349 
        }
350 
        for sa in &bundle.attests {
351 
            let r = self.store.put_attest(&sa.attest)?;
352 
            for sig in &sa.sigs {
353 
                self.store.put_signature(&r, sig)?;
354 
            }
355 
            if let AttestBody::Seal { hashes } = &sa.attest.body {
356 
                for h in hashes {
357 
                    self.store.index_seal(h, &r)?;
358 
                }
359 
            }
360 
        }
361 
        let incoming: BTreeSet<ChangeHash> = bundle.changes.iter().map(|(c, _)| c.hash()).collect();
362 
        let boundary = self.boundary();
363 
        let mut imported = Vec::new();
364 
        for (c, sigs) in &bundle.changes {
365 
            let h = c.hash();
366 
            for d in &c.deps {
367 
                if !self.store.has(d) && !incoming.contains(d) && !shallow && !boundary.contains(d)
368 
                {
369 
                    return fail(format!(
370 
                        "change {} depends on {}, which is neither stored nor in the bundle",
371 
                        h.short(12),
372 
                        d.short(12)
373 
                    ));
374 
                }
375 
            }
376 
            self.store.put_change(c)?;
377 
            for sig in sigs {
378 
                self.store.put_signature(&h, sig)?;
379 
            }
380 
            imported.push(h);
381 
        }
382 
        if strict {
383 
            for h in &imported {
384 
                if !matches!(self.authenticate_change(h)?, SignatureStatus::Valid { .. }) {
385 
                    return fail(format!(
386 
                        "change {} is not authenticated by its author",
387 
                        h.short(12)
388 
                    ));
389 
                }
390 
            }
391 
        }
392 
        Ok(imported)
393 
    }
394
395 
    /// Verify a reference attestation against an update it claims to describe.
396 
    /// `allow_equal` lets a client re-read the attestation it already has; a
397 
    /// server receiving a push requires a strictly greater serial.
398 
    fn check_ref_attest(
399 
        &self,
400 
        sa: &SignedAttest,
401 
        name: &str,
402 
        old_state: &ObjectRef,
403 
        new_state: &ObjectRef,
404 
        last_serial: Option<u64>,
405 
        allow_equal: bool,
406 
    ) -> std::result::Result<u64, String> {
407 
        let AttestBody::Ref {
408 
            name: n,
409 
            old_state: o,
410 
            new_state: nw,
411 
            serial,
412 
        } = &sa.attest.body
413 
        else {
414 
            return Err("attestation is not a ref attestation".into());
415 
        };
416 
        if n != name || o != old_state || nw != new_state {
417 
            return Err("attestation does not describe this update".into());
418 
        }
419 
        if sa.attest.repo != self.id().map_err(|e| e.to_string())? {
420 
            return Err("attestation is for a different repository".into());
421 
        }
422 
        if let Some(last) = last_serial {
423 
            if *serial < last || (*serial == last && !allow_equal) {
424 
                return Err(format!(
425 
                    "attestation serial {serial} is not greater than the last seen {last}"
426 
                ));
427 
            }
428 
        }
429 
        let r = sa.attest.hash();
430 
        let sig = sa.sigs.first().ok_or("attestation carries no signature")?;
431 
        let id = self
432 
            .store
433 
            .get_identity(&sig.key)
434 
            .map_err(|_| format!("unknown key {}", sig.key.short(12)))?;
435 
        verify_signature(&id, sig, Domain::Attest, &r).map_err(|e| e.to_string())?;
436 
        Ok(*serial)
437 
    }
438
439 
    /// Accept a push (spec §16.4). Without a trust policy every repository
440 
    /// is unverified, so unsigned changes and unattested updates are accepted;
441 
    /// attestations that are present must still be valid. With a policy,
442 
    /// every change and update is checked against it. A newer policy in the
443 
    /// push is applied first when it is signed by the current roots.
444 
    pub fn receive_push(
445 
        &self,
446 
        bundle: Bundle,
447 
        updates: Vec<RefUpdate>,
448 
        policy: Option<SignedPolicy>,
449 
        tags: Vec<crate::protocol::TagRef>,
450 
    ) -> Result<Vec<RefResult>> {
451 
        let mut results = Vec::new();
452 
        if let Some(sp) = policy {
453 
            match self.adopt_policy_chain(&bundle.policies, &sp, "push received") {
454 
                Ok(()) => {
455 
                    results.push(RefResult {
456 
                        name: "policy".into(),
457 
                        ok: true,
458 
                        reason: format!("serial {}", sp.policy.serial),
459 
                    });
460 
                }
461 
                Err(e) => {
462 
                    results.push(RefResult {
463 
                        name: "policy".into(),
464 
                        ok: false,
465 
                        reason: e,
466 
                    });
467 
                    for u in updates {
468 
                        results.push(RefResult {
469 
                            name: u.name,
470 
                            ok: false,
471 
                            reason: "policy update was rejected".into(),
472 
                        });
473 
                    }
474 
                    return Ok(results);
475 
                }
476 
            }
477 
        }
478 
        let policy = self.current_policy()?.map(|(_, sp)| sp.policy);
479 
        if let Err(e) = self.import_bundle(&bundle, policy.is_some()) {
480 
            for u in updates {
481 
                results.push(RefResult {
482 
                    name: u.name,
483 
                    ok: false,
484 
                    reason: e.to_string(),
485 
                });
486 
            }
487 
            return Ok(results);
488 
        }
489 
        let (op_ref, op) = self.head_op()?;
490 
        let mut view = op.view.clone();
491 
        let mut names = Vec::new();
492 
        for u in updates {
493 
            let outcome = self.apply_update(&mut view, &u, policy.as_ref());
494 
            let (ok, reason) = match outcome {
495 
                Ok(()) => (true, String::new()),
496 
                Err(e) => (false, e),
497 
            };
498 
            if ok {
499 
                names.push(u.name.clone());
500 
            }
501 
            results.push(RefResult {
502 
                name: u.name,
503 
                ok,
504 
                reason,
505 
            });
506 
        }
507 
        for t in &tags {
508 
            let name = format!("tags/{}", t.name);
509 
            match self.adopt_tag(&mut view, t, policy.as_ref()) {
510 
                Ok(()) => {
511 
                    names.push(name.clone());
512 
                    results.push(RefResult {
513 
                        name,
514 
                        ok: true,
515 
                        reason: String::new(),
516 
                    });
517 
                }
518 
                Err(e) => results.push(RefResult {
519 
                    name,
520 
                    ok: false,
521 
                    reason: e,
522 
                }),
523 
            }
524 
        }
525 
        if !names.is_empty() {
526 
            self.record_op(
527 
                &[op_ref],
528 
                &format!("push received: {}", names.join(" ")),
529 
                view,
530 
            )?;
531 
        }
532 
        Ok(results)
533 
    }
534
535 
    fn apply_update(
536 
        &self,
537 
        view: &mut View,
538 
        u: &RefUpdate,
539 
        policy: Option<&crate::policy::Policy>,
540 
    ) -> std::result::Result<(), String> {
541 
        if u.name == "policy" {
542 
            return Err(
543 
                "the policy reference is updated by sending a policy, not a bookmark update".into(),
544 
            );
545 
        }
546 
        let empty = self
547 
            .store
548 
            .put_state(&StateObject::new(vec![]))
549 
            .map_err(|e| e.to_string())?;
550 
        let current = view.bookmarks.get(&u.name).copied().unwrap_or(empty);
551 
        if current != u.old_state {
552 
            return Err("stale: the remote bookmark has moved; pull first".into());
553 
        }
554 
        let new_state = self
555 
            .store
556 
            .get_state(&u.new_state)
557 
            .map_err(|_| "new state object is missing".to_string())?;
558 
        for h in &new_state.heads {
559 
            if !self.store.has(h) {
560 
                return Err(format!("head {} is missing", h.short(12)));
561 
            }
562 
        }
563 
        if !u.force {
564 
            let old_heads = self
565 
                .store
566 
                .get_state(&current)
567 
                .map_err(|e| e.to_string())?
568 
                .heads;
569 
            let closure = self
570 
                .closure_in_store(&new_state.heads)
571 
                .map_err(|e| e.to_string())?;
572 
            if let Some(h) = old_heads.iter().find(|h| !closure.contains(h)) {
573 
                return Err(format!(
574 
                    "not a fast-forward: current head {} would be dropped (use --force)",
575 
                    h.short(12)
576 
                ));
577 
            }
578 
        }
579 
        if let Some(p) = policy {
580 
            let Some(sa) = &u.attestation else {
581 
                return Err(format!(
582 
                    "{:?} requires a signed reference attestation under this repository's policy",
583 
                    u.name
584 
                ));
585 
            };
586 
            let signer = sa
587 
                .sigs
588 
                .first()
589 
                .map(|s| s.key)
590 
                .ok_or("attestation carries no signature")?;
591 
            if !p.authorizes(&signer, &u.name) {
592 
                return Err(format!(
593 
                    "key {} may not update {:?} under this repository's policy",
594 
                    signer.short(12),
595 
                    u.name
596 
                ));
597 
            }
598 
            let old_heads = self
599 
                .store
600 
                .get_state(&current)
601 
                .map_err(|e| e.to_string())?
602 
                .heads;
603 
            self.state_allowed(&old_heads, &new_state.heads, p, &u.name)?;
604 
        }
605 
        if let Some(sa) = &u.attestation {
606 
            let last = self
607 
                .latest_ref_attest(&u.name)
608 
                .map_err(|e| e.to_string())?
609 
                .and_then(|(_, a)| match a.attest.body {
610 
                    AttestBody::Ref { serial, .. } => Some(serial),
611 
                    _ => None,
612 
                });
613 
            self.check_ref_attest(sa, &u.name, &u.old_state, &u.new_state, last, false)?;
614 
            let r = self
615 
                .store
616 
                .put_attest(&sa.attest)
617 
                .map_err(|e| e.to_string())?;
618 
            for sig in &sa.sigs {
619 
                self.store
620 
                    .put_signature(&r, sig)
621 
                    .map_err(|e| e.to_string())?;
622 
            }
623 
            self.set_ref_attest(&u.name, &r)
624 
                .map_err(|e| e.to_string())?;
625 
        }
626 
        view.bookmarks.insert(u.name.clone(), u.new_state);
627 
        Ok(())
628 
    }
629
630 
    // ------------------------------------------------------------ client side
631
632 
    fn remote_url(&self, name: &str) -> Result<String> {
633 
        self.config.remotes.get(name).cloned().ok_or_else(|| {
634 
            RepoError::Msg(format!(
635 
                "no remote named {name:?}; add one with `oxy remote add`"
636 
            ))
637 
        })
638 
    }
639
640 
    /// Credentials and trust for a remote: `remote.<name>.token` (else
641 
    /// `$OXY_TOKEN`) and `remote.<name>.ca` (else `$OXY_CA`).
642 
    /// Refuse a remote that is another repository. An **unbound** remote
643 
    /// (id all zero: a hosted repository nobody has pushed to) is accepted
644 
    /// for pushes, which bind it to this repository's id (spec §16.1).
645 
    fn check_remote_id(
646 
        &self,
647 
        remote: &dyn crate::protocol::Remote,
648 
        remote_name: &str,
649 
        allow_unbound: bool,
650 
    ) -> Result<()> {
651 
        let theirs = remote.repo_id()?;
652 
        if theirs == self.id()? {
653 
            return Ok(());
654 
        }
655 
        if theirs == crate::protocol::UNBOUND_ID {
656 
            if allow_unbound {
657 
                return Ok(());
658 
            }
659 
            return fail(format!(
660 
                "remote {remote_name:?} is empty and unbound: push to it first"
661 
            ));
662 
        }
663 
        fail(format!(
664 
            "remote {remote_name:?} is a different repository (repository IDs differ)"
665 
        ))
666 
    }
667
668 
    fn remote_options(&self, name: &str) -> RemoteOptions {
669 
        RemoteOptions {
670 
            repo_id: self.id().ok(),
671 
            token: self
672 
                .config
673 
                .remote_tokens
674 
                .get(name)
675 
                .cloned()
676 
                .or_else(|| std::env::var("OXY_TOKEN").ok()),
677 
            ca: self
678 
                .config
679 
                .remote_cas
680 
                .get(name)
681 
                .map(PathBuf::from)
682 
                .or_else(|| std::env::var("OXY_CA").ok().map(PathBuf::from)),
683 
        }
684 
    }
685
686 
    /// Push seal attestations on their own (hub spec §7.4): a bundle with
687 
    /// no changes and no reference updates, which the receiver stores.
688 
    pub fn push_seals(&self, remote_name: &str, seals: &[ObjectRef]) -> Result<()> {
689 
        let remote = self.open_named_remote(remote_name)?;
690 
        self.check_remote_id(remote.as_ref(), remote_name, false)?;
691 
        let mut bundle = Bundle::default();
692 
        for r in seals {
693 
            let attest = self.store.get_attest(r)?;
694 
            let sigs = self.store.signatures(r)?;
695 
            bundle.attests.push(crate::protocol::SignedAttest { attest, sigs });
696 
        }
697 
        let results = remote.push(bundle, vec![], None, vec![])?;
698 
        if let Some(r) = results.iter().find(|r| !r.ok) {
699 
            return fail(format!("{}: {}", r.name, r.reason));
700 
        }
701 
        Ok(())
702 
    }
703
704 
    /// The remote whose URL starts with `base` (a hub), if configured.
705 
    pub fn remote_for_url(&self, base: &str) -> Option<String> {
706 
        let base = base.trim_end_matches('/');
707 
        self.config.remotes.iter().find(|(_, url)| url.trim_end_matches('/') == base).map(|(name, _)| name.clone())
708 
    }
709
710 
    /// Open a remote by name or, failing that, by URL with the default
711 
    /// credentials (`OXY_TOKEN`, `OXY_CA`).
712 
    pub fn open_remote_at(&self, url: &str) -> Result<(String, Box<dyn crate::protocol::Remote>)> {
713 
        if let Some(name) = self.remote_for_url(url) {
714 
            return Ok((name.clone(), self.open_named_remote(&name)?));
715 
        }
716 
        let options = RemoteOptions {
717 
            token: std::env::var("OXY_TOKEN").ok(),
718 
            ca: std::env::var("OXY_CA").ok().map(PathBuf::from),
719 
            repo_id: self.id().ok(),
720 
        };
721 
        Ok((url.to_string(), open_remote(url, &options)?))
722 
    }
723
724 
    /// Credentials for a URL: those of the configured remote with that
725 
    /// URL, else the environment's.
726 
    pub fn options_for_url(&self, url: &str) -> RemoteOptions {
727 
        match self.remote_for_url(url) {
728 
            Some(name) => self.remote_options(&name),
729 
            None => RemoteOptions {
730 
                token: std::env::var("OXY_TOKEN").ok(),
731 
                ca: std::env::var("OXY_CA").ok().map(PathBuf::from),
732 
                repo_id: self.id().ok(),
733 
            },
734 
        }
735 
    }
736
737 
    fn open_named_remote(&self, name: &str) -> Result<Box<dyn crate::protocol::Remote>> {
738 
        open_remote(&self.remote_url(name)?, &self.remote_options(name))
739 
    }
740
741 
    fn serial_path(&self, remote: &str, bookmark: &str) -> PathBuf {
742 
        self.oxy
743 
            .join("remotes")
744 
            .join(remote)
745 
            .join(format!("{bookmark}.serial"))
746 
    }
747
748 
    fn last_seen_serial(&self, remote: &str, bookmark: &str) -> Option<u64> {
749 
        fs::read_to_string(self.serial_path(remote, bookmark))
750 
            .ok()
751 
            .and_then(|s| s.trim().parse().ok())
752 
    }
753
754 
    fn record_serial(&self, remote: &str, bookmark: &str, serial: u64) -> Result<()> {
755 
        let p = self.serial_path(remote, bookmark);
756 
        fs::create_dir_all(p.parent().unwrap())?;
757 
        write_atomic(&p, serial.to_string().as_bytes())
758 
    }
759
760 
    fn policy_serial_path(&self, remote: &str) -> PathBuf {
761 
        self.oxy.join("remotes").join(remote).join("policy.serial")
762 
    }
763
764 
    /// The highest policy serial `remote` has ever presented.
765 
    fn remote_policy_serial(&self, remote: &str) -> Option<u64> {
766 
        fs::read_to_string(self.policy_serial_path(remote))
767 
            .ok()
768 
            .and_then(|s| s.trim().parse().ok())
769 
    }
770
771 
    fn record_policy_serial(&self, remote: &str, serial: u64) -> Result<()> {
772 
        let p = self.policy_serial_path(remote);
773 
        fs::create_dir_all(p.parent().unwrap())?;
774 
        write_atomic(&p, serial.to_string().as_bytes())
775 
    }
776
777 
    fn lazy_dir(&self) -> PathBuf {
778 
        self.oxy.join("lazy")
779 
    }
780
781 
    /// Remember that `blob` was withheld by `remote` (spec §13.5).
782 
    fn register_lazy(&self, blob: &ObjectRef, remote: &str) -> Result<()> {
783 
        fs::create_dir_all(self.lazy_dir())?;
784 
        write_atomic(&self.lazy_dir().join(blob.to_hex()), remote.as_bytes())
785 
    }
786
787 
    /// Which remote promised an absent blob, if any.
788 
    pub fn lazy_remote(&self, blob: &ObjectRef) -> Option<String> {
789 
        fs::read_to_string(self.lazy_dir().join(blob.to_hex()))
790 
            .ok()
791 
            .map(|s| s.trim().to_string())
792 
    }
793
794 
    /// Fetch an absent blob (and its chunks) from the remote that promised it.
795 
    pub(crate) fn fetch_lazy_blob(&self, blob: &ObjectRef) -> Result<()> {
796 
        let Some(remote_name) = self.lazy_remote(blob) else {
797 
            return Err(RepoError::Store(StoreError::NotFound(*blob)));
798 
        };
799 
        let remote = self.open_named_remote(&remote_name)?;
800 
        let objects = remote.objects(&[*blob])?;
801 
        for (ty, body) in objects {
802 
            if matches!(ty, ObjectType::Blob | ObjectType::Chunk) {
803 
                self.store.put(ty, &body)?;
804 
            }
805 
        }
806 
        if !self.store.has(blob) {
807 
            return fail(format!(
808 
                "{remote_name} did not send blob {}",
809 
                blob.short(12)
810 
            ));
811 
        }
812 
        let _ = fs::remove_file(self.lazy_dir().join(blob.to_hex()));
813 
        Ok(())
814 
    }
815
816 
    /// After importing from `remote`, record every blob the changes reference
817 
    /// that the store lacks as lazily available from that remote.
818 
    fn register_missing_blobs(&self, changes: &[ChangeHash], remote: &str) -> Result<usize> {
819 
        let mut n = 0;
820 
        for h in changes {
821 
            let c = self.store.get_change(h)?;
822 
            for e in &c.edits {
823 
                if let Edit::Replace { old, new, .. } = e {
824 
                    for b in [old, new].into_iter().flatten() {
825 
                        if !self.store.has(b) {
826 
                            self.register_lazy(b, remote)?;
827 
                            n += 1;
828 
                        }
829 
                    }
830 
                }
831 
            }
832 
        }
833 
        Ok(n)
834 
    }
835
836 
    /// Every head this repository knows: bookmarks, remote tracking, working copy.
837 
    pub fn known_heads(&self, view: &View) -> Result<Vec<ChangeHash>> {
838 
        let mut have: BTreeSet<ChangeHash> = BTreeSet::new();
839 
        for st in view
840 
            .bookmarks
841 
            .values()
842 
            .chain(view.remotes.values().flat_map(|b| b.values()))
843 
        {
844 
            if let Ok(s) = self.store.get_state(st) {
845 
                have.extend(s.heads);
846 
            }
847 
        }
848 
        have.extend(view.workspaces.values().copied());
849 
        Ok(have.into_iter().collect())
850 
    }
851
852 
    /// Fetch every bookmark of a remote into `remotes/<name>/bookmarks/*` (spec §10.2).
853 
    pub fn fetch(&self, remote_name: &str) -> Result<FetchReport> {
854 
        let remote = self.open_named_remote(remote_name)?;
855 
        self.check_remote_id(remote.as_ref(), remote_name, false)?;
856 
        let resp = remote.refs()?;
857 
        // Trust policy (spec §14.5). Adopt the remote's policy when it is newer
858 
        // and signed by roots we trust, or on first contact. A remote that
859 
        // once presented a policy may never present none or an older one:
860 
        // that is a downgrade. A remote that never presented one is
861 
        // unverified, and this fetch is checked only as far as possible.
862 
        let local_policy = self.current_policy()?.map(|(_, sp)| sp.policy);
863 
        let seen = self.remote_policy_serial(remote_name);
864 
        let mut unverified = false;
865 
        match &resp.policy {
866 
            Some(sp) => {
867 
                if seen.is_some_and(|s| sp.policy.serial < s) {
868 
                    return fail(format!("{remote_name} presents policy serial {} but presented {} before: refusing the downgrade", sp.policy.serial, seen.unwrap()));
869 
                }
870 
                match &local_policy {
871 
                    Some(l) if sp.policy.serial < l.serial => {}
872 
                    Some(l) if sp.policy.serial == l.serial => {
873 
                        if sp.policy.hash() != l.hash() {
874 
                            return fail(format!(
875 
                                "{remote_name} presents a different policy with the same serial {}",
876 
                                l.serial
877 
                            ));
878 
                        }
879 
                    }
880 
                    _ => {
881 
                        self.adopt_policy_chain(
882 
                            &resp.history,
883 
                            sp,
884 
                            &format!("oxy fetch {remote_name}"),
885 
                        )
886 
                        .map_err(|e| RepoError::Msg(format!("policy from {remote_name}: {e}")))?;
887 
                    }
888 
                }
889 
                self.record_policy_serial(remote_name, sp.policy.serial)?;
890 
            }
891 
            None => {
892 
                if seen.is_some() {
893 
                    return fail(format!("{remote_name} presented a policy before but has none now: refusing the downgrade"));
894 
                }
895 
                unverified = true;
896 
            }
897 
        }
898 
        let policy = if unverified {
899 
            None
900 
        } else {
901 
            self.current_policy()?.map(|(_, sp)| sp.policy)
902 
        };
903 
        let (op_ref, op) = self.head_op()?;
904 
        let mut view = op.view.clone();
905 
        let have = self.known_heads(&view)?;
906 
        let mut report = Vec::new();
907 
        let max_blob = self.config.max_blob;
908 
        for r in resp.refs {
909 
            let needed = remote.negotiate(&have, &r.heads)?;
910 
            let bundle = remote.fetch(&needed, max_blob)?;
911 
            // Changes are not individually re-verified here: the bookmark's
912 
            // attestation (checked below) binds its whole state, and the
913 
            // receiver of the push verified the added changes at that time.
914 
            let imported = self.import_bundle(&bundle, false)?;
915 
            if max_blob.is_some() {
916 
                self.register_missing_blobs(&imported, remote_name)?;
917 
            }
918 
            for h in &r.heads {
919 
                if !self.store.has(h) {
920 
                    return fail(format!("remote did not send head {}", h.short(12)));
921 
                }
922 
            }
923 
            let state = self.store.put_state(&StateObject::new(r.heads.clone()))?;
924 
            if state != r.state {
925 
                return fail(format!(
926 
                    "remote state {} does not match its heads",
927 
                    r.state.short(12)
928 
                ));
929 
            }
930 
            if let Some(p) = &policy {
931 
                let Some(sa) = &r.attestation else {
932 
                    return fail(format!(
933 
                        "{remote_name}/{} has no attestation, which its policy requires",
934 
                        r.name
935 
                    ));
936 
                };
937 
                let signer = sa
938 
                    .sigs
939 
                    .first()
940 
                    .map(|s| s.key)
941 
                    .ok_or_else(|| RepoError::Msg("attestation carries no signature".into()))?;
942 
                if !p.authorizes(&signer, &r.name) {
943 
                    return fail(format!(
944 
                        "{remote_name}/{}: attested by {}, which the policy does not authorize",
945 
                        r.name,
946 
                        signer.short(12)
947 
                    ));
948 
                }
949 
            }
950 
            if let Some(sa) = &r.attestation {
951 
                let AttestBody::Ref {
952 
                    old_state,
953 
                    new_state,
954 
                    ..
955 
                } = &sa.attest.body
956 
                else {
957 
                    return fail("remote sent a non-ref attestation for a bookmark");
958 
                };
959 
                let (old_state, new_state) = (*old_state, *new_state);
960 
                let serial = self
961 
                    .check_ref_attest(
962 
                        sa,
963 
                        &r.name,
964 
                        &old_state,
965 
                        &new_state,
966 
                        self.last_seen_serial(remote_name, &r.name),
967 
                        true,
968 
                    )
969 
                    .map_err(|e| {
970 
                        RepoError::Msg(format!("attestation for {}/{}: {e}", remote_name, r.name))
971 
                    })?;
972 
                if new_state != r.state {
973 
                    return fail(format!(
974 
                        "attestation for {}/{} does not cover its current state",
975 
                        remote_name, r.name
976 
                    ));
977 
                }
978 
                let ar = self.store.put_attest(&sa.attest)?;
979 
                for sig in &sa.sigs {
980 
                    self.store.put_signature(&ar, sig)?;
981 
                }
982 
                self.record_serial(remote_name, &r.name, serial)?;
983 
            }
984 
            view.remotes
985 
                .entry(remote_name.to_string())
986 
                .or_default()
987 
                .insert(r.name.clone(), state);
988 
            report.push((r.name, r.heads, imported.len()));
989 
        }
990 
        let mut new_tags = 0;
991 
        for t in &resp.tags {
992 
            if view.tags.contains_key(&t.name) {
993 
                continue;
994 
            }
995 
            // The tag's changes must be here: fetch them if the bookmarks did not bring them.
996 
            let missing: Vec<ChangeHash> = t
997 
                .heads
998 
                .iter()
999 
                .filter(|h| !self.store.has(h))
1000 
                .copied()
1001 
                .collect();
1002 
            if !missing.is_empty() {
1003 
                let needed = remote.negotiate(&self.known_heads(&view)?, &missing)?;
1004 
                let bundle = remote.fetch(&needed, max_blob)?;
1005 
                self.import_bundle(&bundle, false)?;
1006 
            }
1007 
            self.store.put_state(&StateObject::new(t.heads.clone()))?;
1008 
            self.adopt_tag(&mut view, t, policy.as_ref())
1009 
                .map_err(|e| RepoError::Msg(format!("{remote_name} {}: {e}", t.name)))?;
1010 
            new_tags += 1;
1011 
        }
1012 
        if view != op.view {
1013 
            self.record_op(&[op_ref], &format!("oxy fetch {remote_name}"), view)?;
1014 
        }
1015 
        let _ = self.run_hook(
1016 
            "post-fetch",
1017 
            &format!(
1018 
                "{{\"event\":\"post-fetch\",\"remote\":{},\"bookmarks\":{}}}",
1019 
                json_str(remote_name),
1020 
                json_array(report.iter().map(|(n, heads, _)| format!(
1021 
                    "{{\"name\":{},\"heads\":{}}}",
1022 
                    json_str(n),
1023 
                    json_array(heads.iter().map(|h| json_str(&h.to_hex())))
1024 
                )))
1025 
            ),
1026 
        );
1027 
        Ok(FetchReport {
1028 
            refs: report,
1029 
            unverified,
1030 
            new_tags,
1031 
        })
1032 
    }
1033
1034 
    /// Shallow fetch of the remote's bookmark: its checkpoint as our base,
1035 
    /// the changes within `depth` steps of its heads, and the boundary below.
1036 
    pub fn fetch_shallow(&self, remote_name: &str, depth: u32) -> Result<usize> {
1037 
        let remote = self.open_named_remote(remote_name)?;
1038 
        self.check_remote_id(remote.as_ref(), remote_name, false)?;
1039 
        let resp = remote.refs()?;
1040 
        let bookmark = self.config.bookmark.clone();
1041 
        if let Some(sp) = &resp.policy {
1042 
            self.adopt_policy_chain(&resp.history, sp, "oxy clone --depth")
1043 
                .map_err(|e| RepoError::Msg(format!("policy from {remote_name}: {e}")))?;
1044 
            self.record_policy_serial(remote_name, sp.policy.serial)?;
1045 
        }
1046 
        let Some(r) = resp.refs.into_iter().find(|r| r.name == bookmark) else {
1047 
            return fail(format!("{remote_name} has no bookmark {bookmark:?}"));
1048 
        };
1049 
        if r.heads.is_empty() {
1050 
            return Ok(0);
1051 
        }
1052 
        // Base: the remote's checkpoint of exactly these heads.
1053 
        let cp_bundle = remote.checkpoint(&r.heads)?;
1054 
        let mut cp_ref = None;
1055 
        for (ty, body) in &cp_bundle.objects {
1056 
            let put = self.store.put(*ty, body)?;
1057 
            if *ty == ObjectType::Checkpoint {
1058 
                cp_ref = Some(put);
1059 
            }
1060 
        }
1061 
        let Some(cp_ref) = cp_ref else {
1062 
            return fail(format!("{remote_name} sent no checkpoint"));
1063 
        };
1064 
        self.install_checkpoint(&bookmark, &cp_ref)?;
1065 
        // History window.
1066 
        let wanted = remote.shallow(&r.heads, depth)?;
1067 
        let bundle = remote.fetch(&wanted, self.config.max_blob)?;
1068 
        let imported = self.import_bundle_shallow(&bundle, false)?;
1069 
        if self.config.max_blob.is_some() {
1070 
            self.register_missing_blobs(&imported, remote_name)?;
1071 
        }
1072 
        self.refresh_boundary(&imported)?;
1073 
        if let Some(sa) = &r.attestation {
1074 
            let ar = self.store.put_attest(&sa.attest)?;
1075 
            for sig in &sa.sigs {
1076 
                self.store.put_signature(&ar, sig)?;
1077 
            }
1078 
            if let AttestBody::Ref { serial, .. } = sa.attest.body {
1079 
                self.record_serial(remote_name, &r.name, serial)?;
1080 
            }
1081 
        }
1082 
        let state = self.store.put_state(&StateObject::new(r.heads.clone()))?;
1083 
        let (op_ref, op) = self.head_op()?;
1084 
        let mut view = op.view.clone();
1085 
        view.remotes
1086 
            .entry(remote_name.to_string())
1087 
            .or_default()
1088 
            .insert(r.name.clone(), state);
1089 
        self.record_op(
1090 
            &[op_ref],
1091 
            &format!("oxy fetch {remote_name} --depth {depth}"),
1092 
            view,
1093 
        )?;
1094 
        Ok(imported.len())
1095 
    }
1096
1097 
    /// Fetch, then take the union of the local bookmark's state with the
1098 
    /// remote's: no merge change, conflicts become reified (spec §9.4).
1099 
    pub fn pull(&self, remote_name: &str) -> Result<PullReport> {
1100 
        self.fetch(remote_name)?;
1101 
        let (op_ref, op) = self.head_op()?;
1102 
        let bookmark = self.config.bookmark.clone();
1103 
        let local = self.heads_of(&op.view, &bookmark)?;
1104 
        let Some(remote_state) = op
1105 
            .view
1106 
            .remotes
1107 
            .get(remote_name)
1108 
            .and_then(|b| b.get(&bookmark))
1109 
            .copied()
1110 
        else {
1111 
            return Ok(PullReport {
1112 
                heads: local,
1113 
                changed: false,
1114 
                checked_out: false,
1115 
            });
1116 
        };
1117 
        let remote_heads = self.store.get_state(&remote_state)?.heads;
1118 
        let mut all = local.clone();
1119 
        all.extend(remote_heads);
1120 
        let st = self.load_state(&all)?;
1121 
        let mut heads = st.maximal(&all);
1122 
        heads.sort();
1123 
        let mut sorted_local = local.clone();
1124 
        sorted_local.sort();
1125 
        if heads == sorted_local {
1126 
            return Ok(PullReport {
1127 
                heads,
1128 
                changed: false,
1129 
                checked_out: false,
1130 
            });
1131 
        }
1132 
        let mut view = op.view.clone();
1133 
        view.bookmarks.insert(
1134 
            bookmark.clone(),
1135 
            self.store.put_state(&StateObject::new(heads.clone()))?,
1136 
        );
1137 
        self.record_op(&[op_ref], &format!("oxy pull {remote_name}"), view)?;
1138 
        // Follow along if the working copy was clean and on the old heads.
1139 
        let snap = self.snapshot("oxy pull")?;
1140 
        let clean = snap.wc.tree_ops.is_empty() && snap.wc.edits.is_empty();
1141 
        let mut base = snap.base.maximal(&snap.wc.deps);
1142 
        base.sort();
1143 
        let mut checked_out = false;
1144 
        if clean && base == sorted_local {
1145 
            self.checkout(&heads, false, "oxy pull (checkout)")?;
1146 
            checked_out = true;
1147 
        }
1148 
        Ok(PullReport {
1149 
            heads,
1150 
            changed: true,
1151 
            checked_out,
1152 
        })
1153 
    }
1154
1155 
    /// Push the current bookmark (spec §16.3), sealing this author's unsigned
1156 
    /// changes and attesting the reference when a key is available.
1157 
    pub fn push(&self, remote_name: &str, force: bool) -> Result<Vec<RefResult>> {
1158 
        let bookmark = self.config.bookmark.clone();
1159 
        self.push_bookmark(remote_name, &bookmark, force)
1160 
    }
1161
1162 
    /// `push` for a named bookmark (`oxy push -b NAME`).
1163 
    pub fn push_bookmark(
1164 
        &self,
1165 
        remote_name: &str,
1166 
        bookmark: &str,
1167 
        force: bool,
1168 
    ) -> Result<Vec<RefResult>> {
1169 
        let (op_ref, op) = self.head_op()?;
1170 
        if !op.view.bookmarks.contains_key(bookmark) {
1171 
            return fail(format!("no bookmark {bookmark}"));
1172 
        }
1173 
        let bookmark = bookmark.to_string();
1174 
        let local_heads = self.heads_of(&op.view, &bookmark)?;
1175 
        // pre-push hook: may veto before the remote is contacted.
1176 
        self.run_hook(
1177 
            "pre-push",
1178 
            &format!(
1179 
                "{{\"event\":\"pre-push\",\"remote\":{},\"bookmark\":{},\"heads\":{}}}",
1180 
                json_str(remote_name),
1181 
                json_str(&bookmark),
1182 
                json_array(local_heads.iter().map(|h| json_str(&h.to_hex())))
1183 
            ),
1184 
        )?;
1185 
        let remote = self.open_named_remote(remote_name)?;
1186 
        self.check_remote_id(remote.as_ref(), remote_name, true)?;
1187 
        let resp = remote.refs()?;
1188 
        let local_policy = self.current_policy()?.map(|(_, sp)| sp);
1189 
        let resp_policy_serial = resp.policy.as_ref().map(|p| p.policy.serial);
1190 
        let policy_to_send = match (&local_policy, &resp.policy) {
1191 
            (Some(l), Some(r)) if l.policy.serial > r.policy.serial => Some(l.clone()),
1192 
            (Some(l), None) => Some(l.clone()),
1193 
            (Some(l), Some(r)) if l.policy.serial < r.policy.serial => {
1194 
                return fail(format!(
1195 
                    "{remote_name} has a newer policy (serial {}); fetch first",
1196 
                    r.policy.serial
1197 
                ));
1198 
            }
1199 
            _ => None,
1200 
        };
1201 
        let remote_has_policy = resp.policy.is_some() || policy_to_send.is_some();
1202 
        if remote_has_policy && self.secret_key()?.is_none() {
1203 
            return fail(format!("{remote_name} enforces a trust policy; pushing needs an identity (`oxy identity create`)"));
1204 
        }
1205 
        let remote_tags: BTreeSet<String> = resp.tags.iter().map(|t| t.name.clone()).collect();
1206 
        let tags_to_send: Vec<crate::protocol::TagRef> = self
1207 
            .tag_refs()?
1208 
            .into_iter()
1209 
            .filter(|t| !remote_tags.contains(&t.name))
1210 
            .collect();
1211 
        let refs = resp.refs;
1212 
        let empty = self.store.put_state(&StateObject::new(vec![]))?;
1213 
        let (remote_state, remote_heads, last_serial) =
1214 
            match refs.iter().find(|r| r.name == bookmark) {
1215 
                Some(r) => (r.state, r.heads.clone(), r.last_serial),
1216 
                None => (empty, vec![], None),
1217 
            };
1218 
        let new_state = self
1219 
            .store
1220 
            .put_state(&StateObject::new(local_heads.clone()))?;
1221 
        // A push that carries a policy re-attests the bookmark even when its
1222 
        // state is unchanged, so the current attestation is always by a key
1223 
        // the current policy authorizes (a revoked key's attestation would
1224 
        // otherwise be refused by every later fetch).
1225 
        if new_state == remote_state && policy_to_send.is_none() && tags_to_send.is_empty() {
1226 
            return Ok(vec![RefResult {
1227 
                name: bookmark,
1228 
                ok: true,
1229 
                reason: "already up to date".into(),
1230 
            }]);
1231 
        }
1232 
        for h in &remote_heads {
1233 
            if !self.store.has(h) {
1234 
                return fail(format!(
1235 
                    "the remote has change {} which you do not; pull first",
1236 
                    h.short(12)
1237 
                ));
1238 
            }
1239 
        }
1240 
        if !force {
1241 
            let closure = self.closure_in_store(&local_heads)?;
1242 
            if let Some(h) = remote_heads.iter().find(|h| !closure.contains(h)) {
1243 
                return fail(format!("not a fast-forward: remote head {} is not in your state; pull first or use --force", h.short(12)));
1244 
            }
1245 
        }
1246 
        let to_send = self.negotiate(&remote_heads, &local_heads)?;
1247 
        let mut bundle = self.bundle_for(&to_send)?;
1248 
        let key = self.secret_key()?.map(|(k, _)| k);
1249 
        if let Some(key) = key {
1250 
            // Seal this author's changes that carry no valid authenticator,
1251 
            // and adopt anonymous ones (zero author, spec §14.4).
1252 
            let mut unsigned = Vec::new();
1253 
            for h in &to_send {
1254 
                let c = self.store.get_change(h)?;
1255 
                if (c.author == key || c.author.is_zero())
1256 
                    && !matches!(self.authenticate_change(h)?, SignatureStatus::Valid { .. })
1257 
                {
1258 
                    unsigned.push(*h);
1259 
                }
1260 
            }
1261 
            for chunk in unsigned.chunks(crate::attest::MAX_SEAL_HASHES) {
1262 
                let sa = self.sign_attest(&Attest::seal(self.id()?, chunk.to_vec()))?;
1263 
                bundle.attests.push(sa);
1264 
            }
1265 
            bundle = self.bundle_for(&to_send)?;
1266 
        }
1267 
        bundle.objects.push((
1268 
            ObjectType::State,
1269 
            StateObject::new(local_heads.clone()).encode(),
1270 
        ));
1271 
        let attestation = match key {
1272 
            Some(_) => Some(self.sign_attest(&Attest {
1273 
                repo: self.id()?,
1274 
                hlc: Hlc::now(),
1275 
                body: AttestBody::Ref {
1276 
                    name: bookmark.clone(),
1277 
                    old_state: remote_state,
1278 
                    new_state,
1279 
                    serial: last_serial.unwrap_or(0) + 1,
1280 
                },
1281 
            })?),
1282 
            None => None,
1283 
        };
1284 
        let serial = attestation.as_ref().and_then(|a| match a.attest.body {
1285 
            AttestBody::Ref { serial, .. } => Some(serial),
1286 
            _ => None,
1287 
        });
1288 
        let sent_serial = policy_to_send.as_ref().map(|p| p.policy.serial);
1289 
        // Tag states must be present on the remote: bundle their changes too.
1290 
        for t in &tags_to_send {
1291 
            let extra = self.negotiate(&remote_heads, &t.heads)?;
1292 
            let extra: Vec<ChangeHash> =
1293 
                extra.into_iter().filter(|h| !to_send.contains(h)).collect();
1294 
            if !extra.is_empty() {
1295 
                let more = self.bundle_for(&extra)?;
1296 
                bundle.changes.extend(more.changes);
1297 
                bundle.attests.extend(more.attests);
1298 
                bundle.objects.extend(more.objects);
1299 
            }
1300 
            bundle.objects.push((
1301 
                ObjectType::State,
1302 
                StateObject::new(t.heads.clone()).encode(),
1303 
            ));
1304 
        }
1305 
        if let Some(l) = &policy_to_send {
1306 
            let remote_serial = resp_policy_serial;
1307 
            bundle.policies = self
1308 
                .policy_history()?
1309 
                .into_iter()
1310 
                .filter(|sp| {
1311 
                    remote_serial.is_none_or(|r| sp.policy.serial > r)
1312 
                        && sp.policy.serial < l.policy.serial
1313 
                })
1314 
                .collect();
1315 
        }
1316 
        let results = remote.push(
1317 
            bundle,
1318 
            vec![RefUpdate {
1319 
                name: bookmark.clone(),
1320 
                old_state: remote_state,
1321 
                new_state,
1322 
                force,
1323 
                attestation,
1324 
            }],
1325 
            policy_to_send,
1326 
            tags_to_send,
1327 
        )?;
1328 
        if let (Some(serial), true) = (
1329 
            sent_serial,
1330 
            results.iter().any(|r| r.ok && r.name == "policy"),
1331 
        ) {
1332 
            self.record_policy_serial(remote_name, serial)?;
1333 
        }
1334 
        if results.iter().any(|r| r.ok && r.name == bookmark) {
1335 
            let mut view = op.view.clone();
1336 
            view.remotes
1337 
                .entry(remote_name.to_string())
1338 
                .or_default()
1339 
                .insert(bookmark.clone(), new_state);
1340 
            self.record_op(&[op_ref], &format!("oxy push {remote_name}"), view)?;
1341 
            if let Some(s) = serial {
1342 
                self.record_serial(remote_name, &bookmark, s)?;
1343 
            }
1344 
        }
1345 
        Ok(results)
1346 
    }
1347
1348 
    /// Clone a remote into `dest`: same repository ID, `origin` remote,
1349 
    /// bookmark set to the remote's, working copy checked out.
1350 
    pub fn clone(url: &str, dest: &Path) -> Result<Repo> {
1351 
        Self::clone_with(url, dest, None, &[])
1352 
    }
1353
1354 
    /// Clone, leaving blobs above `max_blob` bytes to be fetched on first
1355 
    /// read, and materializing only `sparse` paths (which implies lazy blobs
1356 
    /// unless a size is given, so out-of-scope binaries are never fetched).
1357 
    pub fn clone_with(
1358 
        url: &str,
1359 
        dest: &Path,
1360 
        max_blob: Option<u64>,
1361 
        sparse: &[String],
1362 
    ) -> Result<Repo> {
1363 
        Self::clone_full(url, dest, max_blob, sparse, None)
1364 
    }
1365
1366 
    /// Shallow clone (spec §17): a checkpoint of the bookmark's heads plus the
1367 
    /// changes within `depth` steps of them; the rest is the boundary.
1368 
    pub fn clone_shallow(
1369 
        url: &str,
1370 
        dest: &Path,
1371 
        depth: u32,
1372 
        max_blob: Option<u64>,
1373 
        sparse: &[String],
1374 
    ) -> Result<Repo> {
1375 
        Self::clone_full(url, dest, max_blob, sparse, Some(depth))
1376 
    }
1377
1378 
    fn clone_full(
1379 
        url: &str,
1380 
        dest: &Path,
1381 
        max_blob: Option<u64>,
1382 
        sparse: &[String],
1383 
        depth: Option<u32>,
1384 
    ) -> Result<Repo> {
1385 
        let options = RemoteOptions {
1386 
            token: std::env::var("OXY_TOKEN").ok(),
1387 
            ca: std::env::var("OXY_CA").ok().map(PathBuf::from),
1388 
            repo_id: None,
1389 
        };
1390 
        let remote = open_remote(url, &options)?;
1391 
        let id = remote.repo_id()?;
1392 
        if id == crate::protocol::UNBOUND_ID {
1393 
            return fail(format!(
1394 
                "{url} is empty and unbound: push a repository to it first"
1395 
            ));
1396 
        }
1397 
        let mut repo = Repo::init_with_id(dest, id)?;
1398 
        repo.config.set("remote.origin.url", url)?;
1399 
        if let Some(m) = max_blob {
1400 
            repo.config.set("filter.max-blob", &m.to_string())?;
1401 
        } else if !sparse.is_empty() {
1402 
            repo.config.set("filter.max-blob", "0")?;
1403 
        }
1404 
        if !sparse.is_empty() {
1405 
            repo.config.set("filter.paths", &sparse.join(","))?;
1406 
        }
1407 
        repo.save_config()?;
1408 
        if let Some(depth) = depth {
1409 
            repo.fetch_shallow("origin", depth)?;
1410 
        } else {
1411 
            repo.fetch("origin")?;
1412 
        }
1413 
        let (op_ref, op) = repo.head_op()?;
1414 
        let bookmark = repo.config.bookmark.clone();
1415 
        if let Some(state) = op
1416 
            .view
1417 
            .remotes
1418 
            .get("origin")
1419 
            .and_then(|b| b.get(&bookmark))
1420 
            .copied()
1421 
        {
1422 
            let heads = repo.store.get_state(&state)?.heads;
1423 
            let mut view = op.view.clone();
1424 
            view.bookmarks.insert(bookmark, state);
1425 
            repo.record_op(&[op_ref], &format!("oxy clone {url}"), view)?;
1426 
            repo.checkout(&heads, false, "oxy clone (checkout)")?;
1427 
        }
1428 
        Ok(repo)
1429 
    }
1430 
}