OXYGENHUB
# eae595568832 oxygen / crates / oxy-core / src / repo / sync.rs
54.2 KiB · Rust · last changed Delegate rule on fetch and tags too 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 push did, for hosts (hub spec §6.12).
6 
#[derive(Clone, Debug, Default)]
7 
pub struct PushReport {
8 
    pub results: Vec<RefResult>,
9 
    /// Accepted reference updates, in request order.
10 
    pub updated: Vec<RefUpdated>,
11 
    /// Changes this push stored that were not already present.
12 
    pub imported: Vec<ChangeHash>,
13 
}
14
15 
#[derive(Clone, Debug)]
16 
pub struct RefUpdated {
17 
    pub name: String,
18 
    pub old_state: ObjectRef,
19 
    pub new_state: ObjectRef,
20 
    pub heads: Vec<ChangeHash>,
21 
}
22
23 
/// What a fetch brought in.
24 
#[derive(Debug, Clone, PartialEq, Eq, Default)]
25 
pub struct FetchReport {
26 
    /// Bookmark name, its heads, and how many changes were new.
27 
    pub refs: Vec<(String, Vec<ChangeHash>, usize)>,
28 
    /// Tags adopted from the remote.
29 
    pub new_tags: usize,
30 
    /// The remote has never presented a policy, so nothing was verified
31 
    /// against one (spec §14.5: warn loudly).
32 
    pub unverified: bool,
33 
}
34
35 
#[derive(Debug, Clone, PartialEq, Eq)]
36 
pub struct PullReport {
37 
    pub heads: Vec<ChangeHash>,
38 
    pub changed: bool,
39 
    pub checked_out: bool,
40 
}
41
42 
impl Repo {
43 
    // ------------------------------------------------------------ serving (spec §16)
44
45 
    fn ref_attest_path(&self, bookmark: &str) -> PathBuf {
46 
        self.oxy.join("attest").join(bookmark)
47 
    }
48
49 
    /// The latest reference attestation stored for a bookmark.
50 
    pub fn latest_ref_attest(&self, bookmark: &str) -> Result<Option<(ObjectRef, SignedAttest)>> {
51 
        match fs::read_to_string(self.ref_attest_path(bookmark)) {
52 
            Ok(h) => {
53 
                let r = ObjectRef::from_hex(h.trim())
54 
                    .ok_or_else(|| RepoError::Msg("corrupt attestation pointer".into()))?;
55 
                Ok(Some((
56 
                    r,
57 
                    SignedAttest {
58 
                        attest: self.store.get_attest(&r)?,
59 
                        sigs: self.store.signatures(&r)?,
60 
                    },
61 
                )))
62 
            }
63 
            Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(None),
64 
            Err(e) => Err(e.into()),
65 
        }
66 
    }
67
68 
    fn set_ref_attest(&self, bookmark: &str, r: &ObjectRef) -> Result<()> {
69 
        fs::create_dir_all(self.oxy.join("attest"))?;
70 
        write_atomic(&self.ref_attest_path(bookmark), r.to_hex().as_bytes())
71 
    }
72
73 
    pub fn remote_refs(&self) -> Result<RefsResponse> {
74 
        let view = self.view()?;
75 
        let mut out = Vec::new();
76 
        for (name, state) in &view.bookmarks {
77 
            let latest = self.latest_ref_attest(name)?.map(|(_, a)| a);
78 
            let last_serial = latest.as_ref().and_then(|a| match a.attest.body {
79 
                AttestBody::Ref { serial, .. } => Some(serial),
80 
                _ => None,
81 
            });
82 
            let attestation = latest.filter(|a| matches!(&a.attest.body, AttestBody::Ref { new_state, .. } if new_state == state));
83 
            out.push(RemoteRef {
84 
                name: name.clone(),
85 
                state: *state,
86 
                heads: self.store.get_state(state)?.heads,
87 
                attestation,
88 
                last_serial,
89 
            });
90 
        }
91 
        let policy = self.current_policy()?.map(|(_, sp)| sp);
92 
        let history = self
93 
            .policy_history()?
94 
            .into_iter()
95 
            .filter(|sp| {
96 
                policy
97 
                    .as_ref()
98 
                    .is_some_and(|p| sp.policy.serial < p.policy.serial)
99 
            })
100 
            .collect();
101 
        Ok(RefsResponse {
102 
            refs: out,
103 
            policy,
104 
            tags: self.tag_refs()?,
105 
            history,
106 
        })
107 
    }
108
109 
    /// Every change reachable from `heads` that is in the store.
110 
    fn closure_in_store(&self, heads: &[ChangeHash]) -> Result<BTreeSet<ChangeHash>> {
111 
        let mut seen = BTreeSet::new();
112 
        let mut stack: Vec<ChangeHash> = heads.to_vec();
113 
        while let Some(h) = stack.pop() {
114 
            if seen.contains(&h) || !self.store.has(&h) {
115 
                continue;
116 
            }
117 
            seen.insert(h);
118 
            stack.extend(self.store.get_change(&h)?.deps);
119 
        }
120 
        Ok(seen)
121 
    }
122
123 
    /// The changes within `depth` dependency steps of `heads` (spec §17),
124 
    /// nearest first; depth 1 is the heads themselves.
125 
    pub fn shallow_changes(&self, heads: &[ChangeHash], depth: u32) -> Result<Vec<ChangeHash>> {
126 
        let mut out = Vec::new();
127 
        let mut seen: BTreeSet<ChangeHash> = BTreeSet::new();
128 
        let mut layer: Vec<ChangeHash> = heads.to_vec();
129 
        for _ in 0..depth.max(1) {
130 
            let mut next = Vec::new();
131 
            for h in layer {
132 
                if !seen.insert(h) || !self.store.has(&h) {
133 
                    continue;
134 
                }
135 
                let c = self.store.get_change(&h)?;
136 
                next.extend(c.deps.iter().copied());
137 
                out.push(h);
138 
            }
139 
            if next.is_empty() {
140 
                break;
141 
            }
142 
            layer = next;
143 
        }
144 
        out.reverse();
145 
        Ok(out)
146 
    }
147
148 
    fn shallow_path(&self) -> PathBuf {
149 
        self.oxy.join("shallow")
150 
    }
151
152 
    /// The shallow boundary: dependencies this repository does not hold (spec §17).
153 
    pub fn boundary(&self) -> BTreeSet<ChangeHash> {
154 
        fs::read_to_string(self.shallow_path())
155 
            .map(|t| t.lines().filter_map(ObjectRef::from_hex).collect())
156 
            .unwrap_or_default()
157 
    }
158
159 
    pub fn is_shallow(&self) -> bool {
160 
        !self.boundary().is_empty()
161 
    }
162
163 
    fn write_boundary(&self, boundary: &BTreeSet<ChangeHash>) -> Result<()> {
164 
        if boundary.is_empty() {
165 
            let _ = fs::remove_file(self.shallow_path());
166 
            return Ok(());
167 
        }
168 
        let text: String = boundary
169 
            .iter()
170 
            .map(|h| format!("{}\n", h.to_hex()))
171 
            .collect();
172 
        write_atomic(&self.shallow_path(), text.as_bytes())
173 
    }
174
175 
    /// Recompute the boundary from what is stored: every dependency of a
176 
    /// stored change that is not itself stored.
177 
    fn refresh_boundary(&self, imported: &[ChangeHash]) -> Result<()> {
178 
        let mut boundary = self.boundary();
179 
        boundary.retain(|h| !self.store.has(h));
180 
        for h in imported {
181 
            for d in self.store.get_change(h)?.deps {
182 
                if !self.store.has(&d) {
183 
                    boundary.insert(d);
184 
                }
185 
            }
186 
        }
187 
        self.write_boundary(&boundary)
188 
    }
189
190 
    /// Fetch `depth` more levels of history below the shallow boundary.
191 
    pub fn deepen(&self, remote_name: &str, depth: u32) -> Result<usize> {
192 
        let boundary = self.boundary();
193 
        if boundary.is_empty() {
194 
            return Ok(0);
195 
        }
196 
        let remote = self.open_named_remote(remote_name)?;
197 
        let wanted = remote.shallow(&boundary.iter().copied().collect::<Vec<_>>(), depth)?;
198 
        let bundle = remote.fetch(&wanted, self.config.max_blob)?;
199 
        let imported = self.import_bundle_shallow(&bundle, false)?;
200 
        if self.config.max_blob.is_some() {
201 
            self.register_missing_blobs(&imported, remote_name)?;
202 
        }
203 
        self.refresh_boundary(&imported)?;
204 
        Ok(imported.len())
205 
    }
206
207 
    /// `closure(want) \ closure(have)`, dependencies first (spec §16.2).
208 
    pub fn negotiate(&self, have: &[ChangeHash], want: &[ChangeHash]) -> Result<Vec<ChangeHash>> {
209 
        let have = self.closure_in_store(have)?;
210 
        // In a shallow repository the walk stops at the boundary, whose
211 
        // changes the remote is assumed to hold.
212 
        let boundary = self.boundary();
213 
        let mut out = Vec::new();
214 
        let mut done: BTreeSet<ChangeHash> = have.clone();
215 
        done.extend(boundary.iter().copied());
216 
        // Iterative post-order DFS.
217 
        let mut stack: Vec<(ChangeHash, bool)> = want.iter().rev().map(|h| (*h, false)).collect();
218 
        while let Some((h, expanded)) = stack.pop() {
219 
            if done.contains(&h) {
220 
                continue;
221 
            }
222 
            if !self.store.has(&h) {
223 
                return fail(format!("change {} is not in this repository", h.short(12)));
224 
            }
225 
            if expanded {
226 
                done.insert(h);
227 
                out.push(h);
228 
                continue;
229 
            }
230 
            stack.push((h, true));
231 
            for d in self.store.get_change(&h)?.deps {
232 
                if !done.contains(&d) {
233 
                    stack.push((d, false));
234 
                }
235 
            }
236 
        }
237 
        Ok(out)
238 
    }
239
240 
    /// Bundle changes (in the given dependency order) with their signatures,
241 
    /// seals, identities, blobs, chunks.
242 
    pub fn bundle_for(&self, changes: &[ChangeHash]) -> Result<Bundle> {
243 
        self.bundle_for_filtered(changes, None)
244 
    }
245
246 
    /// Objects by reference for the `objects` endpoint; a blob brings its chunks.
247 
    pub fn objects_for(&self, refs: &[ObjectRef]) -> Result<Vec<(ObjectType, Vec<u8>)>> {
248 
        let mut out = Vec::new();
249 
        for r in refs {
250 
            let (ty, body) = match self.store.get(r) {
251 
                Ok(x) => x,
252 
                Err(StoreError::NotFound(_)) => continue,
253 
                Err(e) => return Err(e.into()),
254 
            };
255 
            if ty == ObjectType::Blob {
256 
                for c in Blob::decode(&body)?.chunks {
257 
                    if let Ok((cty, cb)) = self.store.get(&c) {
258 
                        out.push((cty, cb));
259 
                    }
260 
                }
261 
            }
262 
            out.push((ty, body));
263 
        }
264 
        Ok(out)
265 
    }
266
267 
    /// Like `bundle_for`, leaving out blobs larger than `max_blob` bytes
268 
    /// (and their chunks) so the receiver fetches them lazily (spec §13.5).
269 
    pub fn bundle_for_filtered(
270 
        &self,
271 
        changes: &[ChangeHash],
272 
        max_blob: Option<u64>,
273 
    ) -> Result<Bundle> {
274 
        let mut bundle = Bundle::default();
275 
        let mut objects: BTreeSet<ObjectRef> = BTreeSet::new();
276 
        let mut seals: BTreeSet<ObjectRef> = BTreeSet::new();
277 
        let add_object = |r: &ObjectRef, objects: &mut BTreeSet<ObjectRef>| {
278 
            if !r.is_zero() && self.store.has(r) {
279 
                objects.insert(*r);
280 
            }
281 
        };
282 
        for h in changes {
283 
            let c = self.store.get_change(h)?;
284 
            let sigs = self.store.signatures(h)?;
285 
            add_object(&c.author, &mut objects);
286 
            for s in &sigs {
287 
                add_object(&s.key, &mut objects);
288 
            }
289 
            for e in &c.edits {
290 
                if let Edit::Replace { old, new, .. } = e {
291 
                    for b in [old, new].into_iter().flatten() {
292 
                        if self.store.has(b) {
293 
                            if let Ok(blob) =
294 
                                Blob::decode(&self.store.get_typed(b, ObjectType::Blob)?)
295 
                            {
296 
                                if max_blob.is_some_and(|m| blob.length > m) {
297 
                                    continue;
298 
                                }
299 
                                objects.insert(*b);
300 
                                objects.extend(blob.chunks.iter().copied());
301 
                            }
302 
                        }
303 
                    }
304 
                }
305 
            }
306 
            for s in self.store.seals_for(h)? {
307 
                seals.insert(s);
308 
            }
309 
            bundle.changes.push((c, sigs));
310 
        }
311 
        for r in seals {
312 
            let attest = self.store.get_attest(&r)?;
313 
            let sigs = self.store.signatures(&r)?;
314 
            for s in &sigs {
315 
                add_object(&s.key, &mut objects);
316 
            }
317 
            bundle.attests.push(SignedAttest { attest, sigs });
318 
        }
319 
        for r in objects {
320 
            let (ty, body) = self.store.get(&r)?;
321 
            bundle.objects.push((ty, body));
322 
        }
323 
        Ok(bundle)
324 
    }
325
326 
    /// Store a bundle's contents. With `strict`, every change must
327 
    /// authenticate (signature or seal by its author or a delegate).
328 
    pub fn import_bundle(&self, bundle: &Bundle, strict: bool) -> Result<Vec<ChangeHash>> {
329 
        self.import_bundle_inner(bundle, strict, false)
330 
    }
331
332 
    /// Like `import_bundle`, accepting changes whose dependencies are absent
333 
    /// (they join the shallow boundary).
334 
    pub fn import_bundle_shallow(&self, bundle: &Bundle, strict: bool) -> Result<Vec<ChangeHash>> {
335 
        self.import_bundle_inner(bundle, strict, true)
336 
    }
337
338 
    fn import_bundle_inner(
339 
        &self,
340 
        bundle: &Bundle,
341 
        strict: bool,
342 
        shallow: bool,
343 
    ) -> Result<Vec<ChangeHash>> {
344 
        let batch = self.store.begin_batch()?;
345 
        let result = self.import_bundle_batched(bundle, strict, shallow);
346 
        batch.finish()?;
347 
        result
348 
    }
349
350 
    fn import_bundle_batched(
351 
        &self,
352 
        bundle: &Bundle,
353 
        strict: bool,
354 
        shallow: bool,
355 
    ) -> Result<Vec<ChangeHash>> {
356 
        for (ty, body) in &bundle.objects {
357 
            match ty {
358 
                ObjectType::Chunk
359 
                | ObjectType::Blob
360 
                | ObjectType::Identity
361 
                | ObjectType::State
362 
                | ObjectType::Checkpoint => {
363 
                    self.store.put(*ty, body)?;
364 
                }
365 
                other => return fail(format!("bundle may not carry {} objects", other.name())),
366 
            }
367 
        }
368 
        for sa in &bundle.attests {
369 
            let r = self.store.put_attest(&sa.attest)?;
370 
            for sig in &sa.sigs {
371 
                self.store.put_signature(&r, sig)?;
372 
            }
373 
            if let AttestBody::Seal { hashes } = &sa.attest.body {
374 
                for h in hashes {
375 
                    self.store.index_seal(h, &r)?;
376 
                }
377 
            }
378 
        }
379 
        let incoming: BTreeSet<ChangeHash> = bundle.changes.iter().map(|(c, _)| c.hash()).collect();
380 
        let boundary = self.boundary();
381 
        let mut imported = Vec::new();
382 
        for (c, sigs) in &bundle.changes {
383 
            let h = c.hash();
384 
            for d in &c.deps {
385 
                if !self.store.has(d) && !incoming.contains(d) && !shallow && !boundary.contains(d)
386 
                {
387 
                    return fail(format!(
388 
                        "change {} depends on {}, which is neither stored nor in the bundle",
389 
                        h.short(12),
390 
                        d.short(12)
391 
                    ));
392 
                }
393 
            }
394 
            self.store.put_change(c)?;
395 
            for sig in sigs {
396 
                self.store.put_signature(&h, sig)?;
397 
            }
398 
            imported.push(h);
399 
        }
400 
        if strict {
401 
            for h in &imported {
402 
                if !matches!(self.authenticate_change(h)?, SignatureStatus::Valid { .. }) {
403 
                    return fail(format!(
404 
                        "change {} is not authenticated by its author",
405 
                        h.short(12)
406 
                    ));
407 
                }
408 
            }
409 
        }
410 
        Ok(imported)
411 
    }
412
413 
    /// Verify a reference attestation against an update it claims to describe.
414 
    /// `allow_equal` lets a client re-read the attestation it already has; a
415 
    /// server receiving a push requires a strictly greater serial.
416 
    /// A reference attestation signed by a delegate of an identity the
417 
    /// rule lists is authorized as that identity (spec §14.5): the identity
418 
    /// named the delegate, and the policy names the identity. Revoked keys
419 
    /// authorize nothing either way.
420 
    pub(crate) fn delegate_authorized(
421 
        &self,
422 
        p: &crate::policy::Policy,
423 
        signer: &KeyId,
424 
        reference: &str,
425 
    ) -> bool {
426 
        if p.is_revoked(signer) {
427 
            return false;
428 
        }
429 
        let Some(rule) = p.rule_for(reference) else {
430 
            return false;
431 
        };
432 
        rule.keys.iter().any(|k| {
433 
            !p.is_revoked(k)
434 
                && p.identity(k)
435 
                    .cloned()
436 
                    .or_else(|| self.store.get_identity(k).ok())
437 
                    .is_some_and(|id| id.delegates.contains(signer))
438 
        })
439 
    }
440
441 
    fn check_ref_attest(
442 
        &self,
443 
        sa: &SignedAttest,
444 
        name: &str,
445 
        old_state: &ObjectRef,
446 
        new_state: &ObjectRef,
447 
        last_serial: Option<u64>,
448 
        allow_equal: bool,
449 
    ) -> std::result::Result<u64, String> {
450 
        let AttestBody::Ref {
451 
            name: n,
452 
            old_state: o,
453 
            new_state: nw,
454 
            serial,
455 
        } = &sa.attest.body
456 
        else {
457 
            return Err("attestation is not a ref attestation".into());
458 
        };
459 
        if n != name || o != old_state || nw != new_state {
460 
            return Err("attestation does not describe this update".into());
461 
        }
462 
        if sa.attest.repo != self.id().map_err(|e| e.to_string())? {
463 
            return Err("attestation is for a different repository".into());
464 
        }
465 
        if let Some(last) = last_serial {
466 
            if *serial < last || (*serial == last && !allow_equal) {
467 
                return Err(format!(
468 
                    "attestation serial {serial} is not greater than the last seen {last}"
469 
                ));
470 
            }
471 
        }
472 
        let r = sa.attest.hash();
473 
        let sig = sa.sigs.first().ok_or("attestation carries no signature")?;
474 
        let id = self
475 
            .store
476 
            .get_identity(&sig.key)
477 
            .map_err(|_| format!("unknown key {}", sig.key.short(12)))?;
478 
        verify_signature(&id, sig, Domain::Attest, &r).map_err(|e| e.to_string())?;
479 
        Ok(*serial)
480 
    }
481
482 
    /// Accept a push (spec §16.4). Without a trust policy every repository
483 
    /// is unverified, so unsigned changes and unattested updates are accepted;
484 
    /// attestations that are present must still be valid. With a policy,
485 
    /// every change and update is checked against it. A newer policy in the
486 
    /// push is applied first when it is signed by the current roots.
487 
    pub fn receive_push(
488 
        &self,
489 
        bundle: Bundle,
490 
        updates: Vec<RefUpdate>,
491 
        policy: Option<SignedPolicy>,
492 
        tags: Vec<crate::protocol::TagRef>,
493 
    ) -> Result<Vec<RefResult>> {
494 
        Ok(self
495 
            .receive_push_report(bundle, updates, policy, tags)?
496 
            .results)
497 
    }
498
499 
    /// `receive_push` with what a host wants to log: each accepted
500 
    /// reference's old and new state and heads, and the changes this push
501 
    /// stored (hub spec §6.12).
502 
    pub fn receive_push_report(
503 
        &self,
504 
        bundle: Bundle,
505 
        updates: Vec<RefUpdate>,
506 
        policy: Option<SignedPolicy>,
507 
        tags: Vec<crate::protocol::TagRef>,
508 
    ) -> Result<PushReport> {
509 
        let mut report = PushReport::default();
510 
        let results = &mut report.results;
511 
        if let Some(sp) = policy {
512 
            match self.adopt_policy_chain(&bundle.policies, &sp, "push received") {
513 
                Ok(()) => {
514 
                    results.push(RefResult {
515 
                        name: "policy".into(),
516 
                        ok: true,
517 
                        reason: format!("serial {}", sp.policy.serial),
518 
                    });
519 
                }
520 
                Err(e) => {
521 
                    results.push(RefResult {
522 
                        name: "policy".into(),
523 
                        ok: false,
524 
                        reason: e,
525 
                    });
526 
                    for u in updates {
527 
                        results.push(RefResult {
528 
                            name: u.name,
529 
                            ok: false,
530 
                            reason: "policy update was rejected".into(),
531 
                        });
532 
                    }
533 
                    return Ok(report);
534 
                }
535 
            }
536 
        }
537 
        let policy = self.current_policy()?.map(|(_, sp)| sp.policy);
538 
        match self.import_bundle(&bundle, policy.is_some()) {
539 
            Ok(imported) => report.imported = imported,
540 
            Err(e) => {
541 
                for u in updates {
542 
                    results.push(RefResult {
543 
                        name: u.name,
544 
                        ok: false,
545 
                        reason: e.to_string(),
546 
                    });
547 
                }
548 
                return Ok(report);
549 
            }
550 
        }
551 
        let (op_ref, op) = self.head_op()?;
552 
        let mut view = op.view.clone();
553 
        let mut names = Vec::new();
554 
        for u in updates {
555 
            let outcome = self.apply_update(&mut view, &u, policy.as_ref());
556 
            let (ok, reason) = match outcome {
557 
                Ok(()) => (true, String::new()),
558 
                Err(e) => (false, e),
559 
            };
560 
            if ok {
561 
                names.push(u.name.clone());
562 
                let heads = self
563 
                    .store
564 
                    .get_state(&u.new_state)
565 
                    .map(|s| s.heads)
566 
                    .unwrap_or_default();
567 
                report.updated.push(RefUpdated {
568 
                    name: u.name.clone(),
569 
                    old_state: u.old_state,
570 
                    new_state: u.new_state,
571 
                    heads,
572 
                });
573 
            }
574 
            results.push(RefResult {
575 
                name: u.name,
576 
                ok,
577 
                reason,
578 
            });
579 
        }
580 
        for t in &tags {
581 
            let name = format!("tags/{}", t.name);
582 
            match self.adopt_tag(&mut view, t, policy.as_ref()) {
583 
                Ok(()) => {
584 
                    names.push(name.clone());
585 
                    results.push(RefResult {
586 
                        name,
587 
                        ok: true,
588 
                        reason: String::new(),
589 
                    });
590 
                }
591 
                Err(e) => results.push(RefResult {
592 
                    name,
593 
                    ok: false,
594 
                    reason: e,
595 
                }),
596 
            }
597 
        }
598 
        if !names.is_empty() {
599 
            self.record_op(
600 
                &[op_ref],
601 
                &format!("push received: {}", names.join(" ")),
602 
                view,
603 
            )?;
604 
        }
605 
        Ok(report)
606 
    }
607
608 
    fn apply_update(
609 
        &self,
610 
        view: &mut View,
611 
        u: &RefUpdate,
612 
        policy: Option<&crate::policy::Policy>,
613 
    ) -> std::result::Result<(), String> {
614 
        if u.name == "policy" {
615 
            return Err(
616 
                "the policy reference is updated by sending a policy, not a bookmark update".into(),
617 
            );
618 
        }
619 
        let empty = self
620 
            .store
621 
            .put_state(&StateObject::new(vec![]))
622 
            .map_err(|e| e.to_string())?;
623 
        let current = view.bookmarks.get(&u.name).copied().unwrap_or(empty);
624 
        if current != u.old_state {
625 
            return Err("stale: the remote bookmark has moved; pull first".into());
626 
        }
627 
        let new_state = self
628 
            .store
629 
            .get_state(&u.new_state)
630 
            .map_err(|_| "new state object is missing".to_string())?;
631 
        for h in &new_state.heads {
632 
            if !self.store.has(h) {
633 
                return Err(format!("head {} is missing", h.short(12)));
634 
            }
635 
        }
636 
        if !u.force {
637 
            let old_heads = self
638 
                .store
639 
                .get_state(&current)
640 
                .map_err(|e| e.to_string())?
641 
                .heads;
642 
            let closure = self
643 
                .closure_in_store(&new_state.heads)
644 
                .map_err(|e| e.to_string())?;
645 
            if let Some(h) = old_heads.iter().find(|h| !closure.contains(h)) {
646 
                return Err(format!(
647 
                    "not a fast-forward: current head {} would be dropped (use --force)",
648 
                    h.short(12)
649 
                ));
650 
            }
651 
        }
652 
        if let Some(p) = policy {
653 
            let Some(sa) = &u.attestation else {
654 
                return Err(format!(
655 
                    "{:?} requires a signed reference attestation under this repository's policy",
656 
                    u.name
657 
                ));
658 
            };
659 
            let signer = sa
660 
                .sigs
661 
                .first()
662 
                .map(|s| s.key)
663 
                .ok_or("attestation carries no signature")?;
664 
            if !p.authorizes(&signer, &u.name) && !self.delegate_authorized(p, &signer, &u.name) {
665 
                return Err(format!(
666 
                    "key {} may not update {:?} under this repository's policy",
667 
                    signer.short(12),
668 
                    u.name
669 
                ));
670 
            }
671 
            let old_heads = self
672 
                .store
673 
                .get_state(&current)
674 
                .map_err(|e| e.to_string())?
675 
                .heads;
676 
            self.state_allowed(&old_heads, &new_state.heads, p, &u.name)?;
677 
        }
678 
        if let Some(sa) = &u.attestation {
679 
            let last = self
680 
                .latest_ref_attest(&u.name)
681 
                .map_err(|e| e.to_string())?
682 
                .and_then(|(_, a)| match a.attest.body {
683 
                    AttestBody::Ref { serial, .. } => Some(serial),
684 
                    _ => None,
685 
                });
686 
            self.check_ref_attest(sa, &u.name, &u.old_state, &u.new_state, last, false)?;
687 
            let r = self
688 
                .store
689 
                .put_attest(&sa.attest)
690 
                .map_err(|e| e.to_string())?;
691 
            for sig in &sa.sigs {
692 
                self.store
693 
                    .put_signature(&r, sig)
694 
                    .map_err(|e| e.to_string())?;
695 
            }
696 
            self.set_ref_attest(&u.name, &r)
697 
                .map_err(|e| e.to_string())?;
698 
        }
699 
        view.bookmarks.insert(u.name.clone(), u.new_state);
700 
        Ok(())
701 
    }
702
703 
    // ------------------------------------------------------------ client side
704
705 
    fn remote_url(&self, name: &str) -> Result<String> {
706 
        self.config.remotes.get(name).cloned().ok_or_else(|| {
707 
            RepoError::Msg(format!(
708 
                "no remote named {name:?}; add one with `oxy remote add`"
709 
            ))
710 
        })
711 
    }
712
713 
    /// Credentials and trust for a remote: `remote.<name>.token` (else
714 
    /// `$OXY_TOKEN`) and `remote.<name>.ca` (else `$OXY_CA`).
715 
    /// Refuse a remote that is another repository. An **unbound** remote
716 
    /// (id all zero: a hosted repository nobody has pushed to) is accepted
717 
    /// for pushes, which bind it to this repository's id (spec §16.1).
718 
    fn check_remote_id(
719 
        &self,
720 
        remote: &dyn crate::protocol::Remote,
721 
        remote_name: &str,
722 
        allow_unbound: bool,
723 
    ) -> Result<()> {
724 
        let theirs = remote.repo_id()?;
725 
        if theirs == self.id()? {
726 
            return Ok(());
727 
        }
728 
        if theirs == crate::protocol::UNBOUND_ID {
729 
            if allow_unbound {
730 
                return Ok(());
731 
            }
732 
            return fail(format!(
733 
                "remote {remote_name:?} is empty and unbound: push to it first"
734 
            ));
735 
        }
736 
        fail(format!(
737 
            "remote {remote_name:?} is a different repository (repository IDs differ)"
738 
        ))
739 
    }
740
741 
    fn remote_options(&self, name: &str) -> RemoteOptions {
742 
        RemoteOptions {
743 
            repo_id: self.id().ok(),
744 
            token: self
745 
                .config
746 
                .remote_tokens
747 
                .get(name)
748 
                .cloned()
749 
                .or_else(|| std::env::var("OXY_TOKEN").ok()),
750 
            ca: self
751 
                .config
752 
                .remote_cas
753 
                .get(name)
754 
                .map(PathBuf::from)
755 
                .or_else(|| std::env::var("OXY_CA").ok().map(PathBuf::from)),
756 
        }
757 
    }
758
759 
    fn open_named_remote(&self, name: &str) -> Result<Box<dyn crate::protocol::Remote>> {
760 
        open_remote(&self.remote_url(name)?, &self.remote_options(name))
761 
    }
762
763 
    fn serial_path(&self, remote: &str, bookmark: &str) -> PathBuf {
764 
        self.oxy
765 
            .join("remotes")
766 
            .join(remote)
767 
            .join(format!("{bookmark}.serial"))
768 
    }
769
770 
    fn last_seen_serial(&self, remote: &str, bookmark: &str) -> Option<u64> {
771 
        fs::read_to_string(self.serial_path(remote, bookmark))
772 
            .ok()
773 
            .and_then(|s| s.trim().parse().ok())
774 
    }
775
776 
    fn record_serial(&self, remote: &str, bookmark: &str, serial: u64) -> Result<()> {
777 
        let p = self.serial_path(remote, bookmark);
778 
        fs::create_dir_all(p.parent().unwrap())?;
779 
        write_atomic(&p, serial.to_string().as_bytes())
780 
    }
781
782 
    fn policy_serial_path(&self, remote: &str) -> PathBuf {
783 
        self.oxy.join("remotes").join(remote).join("policy.serial")
784 
    }
785
786 
    /// The highest policy serial `remote` has ever presented.
787 
    fn remote_policy_serial(&self, remote: &str) -> Option<u64> {
788 
        fs::read_to_string(self.policy_serial_path(remote))
789 
            .ok()
790 
            .and_then(|s| s.trim().parse().ok())
791 
    }
792
793 
    fn record_policy_serial(&self, remote: &str, serial: u64) -> Result<()> {
794 
        let p = self.policy_serial_path(remote);
795 
        fs::create_dir_all(p.parent().unwrap())?;
796 
        write_atomic(&p, serial.to_string().as_bytes())
797 
    }
798
799 
    fn lazy_dir(&self) -> PathBuf {
800 
        self.oxy.join("lazy")
801 
    }
802
803 
    /// Remember that `blob` was withheld by `remote` (spec §13.5).
804 
    fn register_lazy(&self, blob: &ObjectRef, remote: &str) -> Result<()> {
805 
        fs::create_dir_all(self.lazy_dir())?;
806 
        write_atomic(&self.lazy_dir().join(blob.to_hex()), remote.as_bytes())
807 
    }
808
809 
    /// Which remote promised an absent blob, if any.
810 
    pub fn lazy_remote(&self, blob: &ObjectRef) -> Option<String> {
811 
        fs::read_to_string(self.lazy_dir().join(blob.to_hex()))
812 
            .ok()
813 
            .map(|s| s.trim().to_string())
814 
    }
815
816 
    /// Fetch an absent blob (and its chunks) from the remote that promised it.
817 
    pub(crate) fn fetch_lazy_blob(&self, blob: &ObjectRef) -> Result<()> {
818 
        let Some(remote_name) = self.lazy_remote(blob) else {
819 
            return Err(RepoError::Store(StoreError::NotFound(*blob)));
820 
        };
821 
        let remote = self.open_named_remote(&remote_name)?;
822 
        let objects = remote.objects(&[*blob])?;
823 
        for (ty, body) in objects {
824 
            if matches!(ty, ObjectType::Blob | ObjectType::Chunk) {
825 
                self.store.put(ty, &body)?;
826 
            }
827 
        }
828 
        if !self.store.has(blob) {
829 
            return fail(format!(
830 
                "{remote_name} did not send blob {}",
831 
                blob.short(12)
832 
            ));
833 
        }
834 
        let _ = fs::remove_file(self.lazy_dir().join(blob.to_hex()));
835 
        Ok(())
836 
    }
837
838 
    /// After importing from `remote`, record every blob the changes reference
839 
    /// that the store lacks as lazily available from that remote.
840 
    fn register_missing_blobs(&self, changes: &[ChangeHash], remote: &str) -> Result<usize> {
841 
        let mut n = 0;
842 
        for h in changes {
843 
            let c = self.store.get_change(h)?;
844 
            for e in &c.edits {
845 
                if let Edit::Replace { old, new, .. } = e {
846 
                    for b in [old, new].into_iter().flatten() {
847 
                        if !self.store.has(b) {
848 
                            self.register_lazy(b, remote)?;
849 
                            n += 1;
850 
                        }
851 
                    }
852 
                }
853 
            }
854 
        }
855 
        Ok(n)
856 
    }
857
858 
    /// Every head this repository knows: bookmarks, remote tracking, working copy.
859 
    fn known_heads(&self, view: &View) -> Result<Vec<ChangeHash>> {
860 
        let mut have: BTreeSet<ChangeHash> = BTreeSet::new();
861 
        for st in view
862 
            .bookmarks
863 
            .values()
864 
            .chain(view.remotes.values().flat_map(|b| b.values()))
865 
        {
866 
            if let Ok(s) = self.store.get_state(st) {
867 
                have.extend(s.heads);
868 
            }
869 
        }
870 
        have.extend(view.workspaces.values().copied());
871 
        Ok(have.into_iter().collect())
872 
    }
873
874 
    /// Fetch every bookmark of a remote into `remotes/<name>/bookmarks/*` (spec §10.2).
875 
    pub fn fetch(&self, remote_name: &str) -> Result<FetchReport> {
876 
        let remote = self.open_named_remote(remote_name)?;
877 
        self.check_remote_id(remote.as_ref(), remote_name, false)?;
878 
        let resp = remote.refs()?;
879 
        // Trust policy (spec §14.5). Adopt the remote's policy when it is newer
880 
        // and signed by roots we trust, or on first contact. A remote that
881 
        // once presented a policy may never present none or an older one:
882 
        // that is a downgrade. A remote that never presented one is
883 
        // unverified, and this fetch is checked only as far as possible.
884 
        let local_policy = self.current_policy()?.map(|(_, sp)| sp.policy);
885 
        let seen = self.remote_policy_serial(remote_name);
886 
        let mut unverified = false;
887 
        match &resp.policy {
888 
            Some(sp) => {
889 
                if seen.is_some_and(|s| sp.policy.serial < s) {
890 
                    return fail(format!("{remote_name} presents policy serial {} but presented {} before: refusing the downgrade", sp.policy.serial, seen.unwrap()));
891 
                }
892 
                match &local_policy {
893 
                    Some(l) if sp.policy.serial < l.serial => {}
894 
                    Some(l) if sp.policy.serial == l.serial => {
895 
                        if sp.policy.hash() != l.hash() {
896 
                            return fail(format!(
897 
                                "{remote_name} presents a different policy with the same serial {}",
898 
                                l.serial
899 
                            ));
900 
                        }
901 
                    }
902 
                    _ => {
903 
                        self.adopt_policy_chain(
904 
                            &resp.history,
905 
                            sp,
906 
                            &format!("oxy fetch {remote_name}"),
907 
                        )
908 
                        .map_err(|e| RepoError::Msg(format!("policy from {remote_name}: {e}")))?;
909 
                    }
910 
                }
911 
                self.record_policy_serial(remote_name, sp.policy.serial)?;
912 
            }
913 
            None => {
914 
                if seen.is_some() {
915 
                    return fail(format!("{remote_name} presented a policy before but has none now: refusing the downgrade"));
916 
                }
917 
                unverified = true;
918 
            }
919 
        }
920 
        let policy = if unverified {
921 
            None
922 
        } else {
923 
            self.current_policy()?.map(|(_, sp)| sp.policy)
924 
        };
925 
        let (op_ref, op) = self.head_op()?;
926 
        let mut view = op.view.clone();
927 
        let have = self.known_heads(&view)?;
928 
        let mut report = Vec::new();
929 
        let max_blob = self.config.max_blob;
930 
        for r in resp.refs {
931 
            let needed = remote.negotiate(&have, &r.heads)?;
932 
            let bundle = remote.fetch(&needed, max_blob)?;
933 
            // Changes are not individually re-verified here: the bookmark's
934 
            // attestation (checked below) binds its whole state, and the
935 
            // receiver of the push verified the added changes at that time.
936 
            let imported = self.import_bundle(&bundle, false)?;
937 
            if max_blob.is_some() {
938 
                self.register_missing_blobs(&imported, remote_name)?;
939 
            }
940 
            for h in &r.heads {
941 
                if !self.store.has(h) {
942 
                    return fail(format!("remote did not send head {}", h.short(12)));
943 
                }
944 
            }
945 
            let state = self.store.put_state(&StateObject::new(r.heads.clone()))?;
946 
            if state != r.state {
947 
                return fail(format!(
948 
                    "remote state {} does not match its heads",
949 
                    r.state.short(12)
950 
                ));
951 
            }
952 
            if let Some(p) = &policy {
953 
                let Some(sa) = &r.attestation else {
954 
                    return fail(format!(
955 
                        "{remote_name}/{} has no attestation, which its policy requires",
956 
                        r.name
957 
                    ));
958 
                };
959 
                let signer = sa
960 
                    .sigs
961 
                    .first()
962 
                    .map(|s| s.key)
963 
                    .ok_or_else(|| RepoError::Msg("attestation carries no signature".into()))?;
964 
                if !p.authorizes(&signer, &r.name) && !self.delegate_authorized(p, &signer, &r.name) {
965 
                    return fail(format!(
966 
                        "{remote_name}/{}: attested by {}, which the policy does not authorize",
967 
                        r.name,
968 
                        signer.short(12)
969 
                    ));
970 
                }
971 
            }
972 
            if let Some(sa) = &r.attestation {
973 
                let AttestBody::Ref {
974 
                    old_state,
975 
                    new_state,
976 
                    ..
977 
                } = &sa.attest.body
978 
                else {
979 
                    return fail("remote sent a non-ref attestation for a bookmark");
980 
                };
981 
                let (old_state, new_state) = (*old_state, *new_state);
982 
                let serial = self
983 
                    .check_ref_attest(
984 
                        sa,
985 
                        &r.name,
986 
                        &old_state,
987 
                        &new_state,
988 
                        self.last_seen_serial(remote_name, &r.name),
989 
                        true,
990 
                    )
991 
                    .map_err(|e| {
992 
                        RepoError::Msg(format!("attestation for {}/{}: {e}", remote_name, r.name))
993 
                    })?;
994 
                if new_state != r.state {
995 
                    return fail(format!(
996 
                        "attestation for {}/{} does not cover its current state",
997 
                        remote_name, r.name
998 
                    ));
999 
                }
1000 
                let ar = self.store.put_attest(&sa.attest)?;
1001 
                for sig in &sa.sigs {
1002 
                    self.store.put_signature(&ar, sig)?;
1003 
                }
1004 
                self.record_serial(remote_name, &r.name, serial)?;
1005 
            }
1006 
            view.remotes
1007 
                .entry(remote_name.to_string())
1008 
                .or_default()
1009 
                .insert(r.name.clone(), state);
1010 
            report.push((r.name, r.heads, imported.len()));
1011 
        }
1012 
        let mut new_tags = 0;
1013 
        for t in &resp.tags {
1014 
            if view.tags.contains_key(&t.name) {
1015 
                continue;
1016 
            }
1017 
            // The tag's changes must be here: fetch them if the bookmarks did not bring them.
1018 
            let missing: Vec<ChangeHash> = t
1019 
                .heads
1020 
                .iter()
1021 
                .filter(|h| !self.store.has(h))
1022 
                .copied()
1023 
                .collect();
1024 
            if !missing.is_empty() {
1025 
                let needed = remote.negotiate(&self.known_heads(&view)?, &missing)?;
1026 
                let bundle = remote.fetch(&needed, max_blob)?;
1027 
                self.import_bundle(&bundle, false)?;
1028 
            }
1029 
            self.store.put_state(&StateObject::new(t.heads.clone()))?;
1030 
            self.adopt_tag(&mut view, t, policy.as_ref())
1031 
                .map_err(|e| RepoError::Msg(format!("{remote_name} {}: {e}", t.name)))?;
1032 
            new_tags += 1;
1033 
        }
1034 
        if view != op.view {
1035 
            self.record_op(&[op_ref], &format!("oxy fetch {remote_name}"), view)?;
1036 
        }
1037 
        let _ = self.run_hook(
1038 
            "post-fetch",
1039 
            &format!(
1040 
                "{{\"event\":\"post-fetch\",\"remote\":{},\"bookmarks\":{}}}",
1041 
                json_str(remote_name),
1042 
                json_array(report.iter().map(|(n, heads, _)| format!(
1043 
                    "{{\"name\":{},\"heads\":{}}}",
1044 
                    json_str(n),
1045 
                    json_array(heads.iter().map(|h| json_str(&h.to_hex())))
1046 
                )))
1047 
            ),
1048 
        );
1049 
        Ok(FetchReport {
1050 
            refs: report,
1051 
            unverified,
1052 
            new_tags,
1053 
        })
1054 
    }
1055
1056 
    /// Shallow fetch of the remote's bookmark: its checkpoint as our base,
1057 
    /// the changes within `depth` steps of its heads, and the boundary below.
1058 
    pub fn fetch_shallow(&self, remote_name: &str, depth: u32) -> Result<usize> {
1059 
        let remote = self.open_named_remote(remote_name)?;
1060 
        self.check_remote_id(remote.as_ref(), remote_name, false)?;
1061 
        let resp = remote.refs()?;
1062 
        let bookmark = self.config.bookmark.clone();
1063 
        if let Some(sp) = &resp.policy {
1064 
            self.adopt_policy_chain(&resp.history, sp, "oxy clone --depth")
1065 
                .map_err(|e| RepoError::Msg(format!("policy from {remote_name}: {e}")))?;
1066 
            self.record_policy_serial(remote_name, sp.policy.serial)?;
1067 
        }
1068 
        let Some(r) = resp.refs.into_iter().find(|r| r.name == bookmark) else {
1069 
            return fail(format!("{remote_name} has no bookmark {bookmark:?}"));
1070 
        };
1071 
        if r.heads.is_empty() {
1072 
            return Ok(0);
1073 
        }
1074 
        // Base: the remote's checkpoint of exactly these heads.
1075 
        let cp_bundle = remote.checkpoint(&r.heads)?;
1076 
        let mut cp_ref = None;
1077 
        for (ty, body) in &cp_bundle.objects {
1078 
            let put = self.store.put(*ty, body)?;
1079 
            if *ty == ObjectType::Checkpoint {
1080 
                cp_ref = Some(put);
1081 
            }
1082 
        }
1083 
        let Some(cp_ref) = cp_ref else {
1084 
            return fail(format!("{remote_name} sent no checkpoint"));
1085 
        };
1086 
        self.install_checkpoint(&bookmark, &cp_ref)?;
1087 
        // History window.
1088 
        let wanted = remote.shallow(&r.heads, depth)?;
1089 
        let bundle = remote.fetch(&wanted, self.config.max_blob)?;
1090 
        let imported = self.import_bundle_shallow(&bundle, false)?;
1091 
        if self.config.max_blob.is_some() {
1092 
            self.register_missing_blobs(&imported, remote_name)?;
1093 
        }
1094 
        self.refresh_boundary(&imported)?;
1095 
        if let Some(sa) = &r.attestation {
1096 
            let ar = self.store.put_attest(&sa.attest)?;
1097 
            for sig in &sa.sigs {
1098 
                self.store.put_signature(&ar, sig)?;
1099 
            }
1100 
            if let AttestBody::Ref { serial, .. } = sa.attest.body {
1101 
                self.record_serial(remote_name, &r.name, serial)?;
1102 
            }
1103 
        }
1104 
        let state = self.store.put_state(&StateObject::new(r.heads.clone()))?;
1105 
        let (op_ref, op) = self.head_op()?;
1106 
        let mut view = op.view.clone();
1107 
        view.remotes
1108 
            .entry(remote_name.to_string())
1109 
            .or_default()
1110 
            .insert(r.name.clone(), state);
1111 
        self.record_op(
1112 
            &[op_ref],
1113 
            &format!("oxy fetch {remote_name} --depth {depth}"),
1114 
            view,
1115 
        )?;
1116 
        Ok(imported.len())
1117 
    }
1118
1119 
    /// Fetch, then take the union of the local bookmark's state with the
1120 
    /// remote's: no merge change, conflicts become reified (spec §9.4).
1121 
    pub fn pull(&self, remote_name: &str) -> Result<PullReport> {
1122 
        self.fetch(remote_name)?;
1123 
        let (op_ref, op) = self.head_op()?;
1124 
        let bookmark = self.config.bookmark.clone();
1125 
        let local = self.heads_of(&op.view, &bookmark)?;
1126 
        let Some(remote_state) = op
1127 
            .view
1128 
            .remotes
1129 
            .get(remote_name)
1130 
            .and_then(|b| b.get(&bookmark))
1131 
            .copied()
1132 
        else {
1133 
            return Ok(PullReport {
1134 
                heads: local,
1135 
                changed: false,
1136 
                checked_out: false,
1137 
            });
1138 
        };
1139 
        let remote_heads = self.store.get_state(&remote_state)?.heads;
1140 
        let mut all = local.clone();
1141 
        all.extend(remote_heads);
1142 
        let st = self.load_state(&all)?;
1143 
        let mut heads = st.maximal(&all);
1144 
        heads.sort();
1145 
        let mut sorted_local = local.clone();
1146 
        sorted_local.sort();
1147 
        if heads == sorted_local {
1148 
            return Ok(PullReport {
1149 
                heads,
1150 
                changed: false,
1151 
                checked_out: false,
1152 
            });
1153 
        }
1154 
        let mut view = op.view.clone();
1155 
        view.bookmarks.insert(
1156 
            bookmark.clone(),
1157 
            self.store.put_state(&StateObject::new(heads.clone()))?,
1158 
        );
1159 
        self.record_op(&[op_ref], &format!("oxy pull {remote_name}"), view)?;
1160 
        // Follow along if the working copy was clean and on the old heads.
1161 
        let snap = self.snapshot("oxy pull")?;
1162 
        let clean = snap.wc.tree_ops.is_empty() && snap.wc.edits.is_empty();
1163 
        let mut base = snap.base.maximal(&snap.wc.deps);
1164 
        base.sort();
1165 
        let mut checked_out = false;
1166 
        if clean && base == sorted_local {
1167 
            self.checkout(&heads, false, "oxy pull (checkout)")?;
1168 
            checked_out = true;
1169 
        }
1170 
        Ok(PullReport {
1171 
            heads,
1172 
            changed: true,
1173 
            checked_out,
1174 
        })
1175 
    }
1176
1177 
    /// Push the current bookmark (spec §16.3), sealing this author's unsigned
1178 
    /// changes and attesting the reference when a key is available.
1179 
    pub fn push(&self, remote_name: &str, force: bool) -> Result<Vec<RefResult>> {
1180 
        let bookmark = self.config.bookmark.clone();
1181 
        self.push_bookmark(remote_name, &bookmark, force)
1182 
    }
1183
1184 
    /// `push` for a named bookmark (`oxy push -b NAME`).
1185 
    pub fn push_bookmark(
1186 
        &self,
1187 
        remote_name: &str,
1188 
        bookmark: &str,
1189 
        force: bool,
1190 
    ) -> Result<Vec<RefResult>> {
1191 
        let (op_ref, op) = self.head_op()?;
1192 
        if !op.view.bookmarks.contains_key(bookmark) {
1193 
            return fail(format!("no bookmark {bookmark}"));
1194 
        }
1195 
        let bookmark = bookmark.to_string();
1196 
        let local_heads = self.heads_of(&op.view, &bookmark)?;
1197 
        // pre-push hook: may veto before the remote is contacted.
1198 
        self.run_hook(
1199 
            "pre-push",
1200 
            &format!(
1201 
                "{{\"event\":\"pre-push\",\"remote\":{},\"bookmark\":{},\"heads\":{}}}",
1202 
                json_str(remote_name),
1203 
                json_str(&bookmark),
1204 
                json_array(local_heads.iter().map(|h| json_str(&h.to_hex())))
1205 
            ),
1206 
        )?;
1207 
        let remote = self.open_named_remote(remote_name)?;
1208 
        self.check_remote_id(remote.as_ref(), remote_name, true)?;
1209 
        let resp = remote.refs()?;
1210 
        let local_policy = self.current_policy()?.map(|(_, sp)| sp);
1211 
        let resp_policy_serial = resp.policy.as_ref().map(|p| p.policy.serial);
1212 
        let policy_to_send = match (&local_policy, &resp.policy) {
1213 
            (Some(l), Some(r)) if l.policy.serial > r.policy.serial => Some(l.clone()),
1214 
            (Some(l), None) => Some(l.clone()),
1215 
            (Some(l), Some(r)) if l.policy.serial < r.policy.serial => {
1216 
                return fail(format!(
1217 
                    "{remote_name} has a newer policy (serial {}); fetch first",
1218 
                    r.policy.serial
1219 
                ));
1220 
            }
1221 
            _ => None,
1222 
        };
1223 
        let remote_has_policy = resp.policy.is_some() || policy_to_send.is_some();
1224 
        if remote_has_policy && self.secret_key()?.is_none() {
1225 
            return fail(format!("{remote_name} enforces a trust policy; pushing needs an identity (`oxy identity create`)"));
1226 
        }
1227 
        let remote_tags: BTreeSet<String> = resp.tags.iter().map(|t| t.name.clone()).collect();
1228 
        let tags_to_send: Vec<crate::protocol::TagRef> = self
1229 
            .tag_refs()?
1230 
            .into_iter()
1231 
            .filter(|t| !remote_tags.contains(&t.name))
1232 
            .collect();
1233 
        let refs = resp.refs;
1234 
        let empty = self.store.put_state(&StateObject::new(vec![]))?;
1235 
        let (remote_state, remote_heads, last_serial) =
1236 
            match refs.iter().find(|r| r.name == bookmark) {
1237 
                Some(r) => (r.state, r.heads.clone(), r.last_serial),
1238 
                None => (empty, vec![], None),
1239 
            };
1240 
        let new_state = self
1241 
            .store
1242 
            .put_state(&StateObject::new(local_heads.clone()))?;
1243 
        // A push that carries a policy re-attests the bookmark even when its
1244 
        // state is unchanged, so the current attestation is always by a key
1245 
        // the current policy authorizes (a revoked key's attestation would
1246 
        // otherwise be refused by every later fetch).
1247 
        if new_state == remote_state && policy_to_send.is_none() && tags_to_send.is_empty() {
1248 
            return Ok(vec![RefResult {
1249 
                name: bookmark,
1250 
                ok: true,
1251 
                reason: "already up to date".into(),
1252 
            }]);
1253 
        }
1254 
        for h in &remote_heads {
1255 
            if !self.store.has(h) {
1256 
                return fail(format!(
1257 
                    "the remote has change {} which you do not; pull first",
1258 
                    h.short(12)
1259 
                ));
1260 
            }
1261 
        }
1262 
        if !force {
1263 
            let closure = self.closure_in_store(&local_heads)?;
1264 
            if let Some(h) = remote_heads.iter().find(|h| !closure.contains(h)) {
1265 
                return fail(format!("not a fast-forward: remote head {} is not in your state; pull first or use --force", h.short(12)));
1266 
            }
1267 
        }
1268 
        let to_send = self.negotiate(&remote_heads, &local_heads)?;
1269 
        let mut bundle = self.bundle_for(&to_send)?;
1270 
        let key = self.secret_key()?.map(|(k, _)| k);
1271 
        if let Some(key) = key {
1272 
            // Seal this author's changes that carry no valid authenticator,
1273 
            // and adopt anonymous ones (zero author, spec §14.4).
1274 
            let mut unsigned = Vec::new();
1275 
            for h in &to_send {
1276 
                let c = self.store.get_change(h)?;
1277 
                if (c.author == key || c.author.is_zero())
1278 
                    && !matches!(self.authenticate_change(h)?, SignatureStatus::Valid { .. })
1279 
                {
1280 
                    unsigned.push(*h);
1281 
                }
1282 
            }
1283 
            for chunk in unsigned.chunks(crate::attest::MAX_SEAL_HASHES) {
1284 
                let sa = self.sign_attest(&Attest::seal(self.id()?, chunk.to_vec()))?;
1285 
                bundle.attests.push(sa);
1286 
            }
1287 
            bundle = self.bundle_for(&to_send)?;
1288 
        }
1289 
        bundle.objects.push((
1290 
            ObjectType::State,
1291 
            StateObject::new(local_heads.clone()).encode(),
1292 
        ));
1293 
        let attestation = match key {
1294 
            Some(_) => Some(self.sign_attest(&Attest {
1295 
                repo: self.id()?,
1296 
                hlc: Hlc::now(),
1297 
                body: AttestBody::Ref {
1298 
                    name: bookmark.clone(),
1299 
                    old_state: remote_state,
1300 
                    new_state,
1301 
                    serial: last_serial.unwrap_or(0) + 1,
1302 
                },
1303 
            })?),
1304 
            None => None,
1305 
        };
1306 
        let serial = attestation.as_ref().and_then(|a| match a.attest.body {
1307 
            AttestBody::Ref { serial, .. } => Some(serial),
1308 
            _ => None,
1309 
        });
1310 
        let sent_serial = policy_to_send.as_ref().map(|p| p.policy.serial);
1311 
        // Tag states must be present on the remote: bundle their changes too.
1312 
        for t in &tags_to_send {
1313 
            let extra = self.negotiate(&remote_heads, &t.heads)?;
1314 
            let extra: Vec<ChangeHash> =
1315 
                extra.into_iter().filter(|h| !to_send.contains(h)).collect();
1316 
            if !extra.is_empty() {
1317 
                let more = self.bundle_for(&extra)?;
1318 
                bundle.changes.extend(more.changes);
1319 
                bundle.attests.extend(more.attests);
1320 
                bundle.objects.extend(more.objects);
1321 
            }
1322 
            bundle.objects.push((
1323 
                ObjectType::State,
1324 
                StateObject::new(t.heads.clone()).encode(),
1325 
            ));
1326 
        }
1327 
        if let Some(l) = &policy_to_send {
1328 
            let remote_serial = resp_policy_serial;
1329 
            bundle.policies = self
1330 
                .policy_history()?
1331 
                .into_iter()
1332 
                .filter(|sp| {
1333 
                    remote_serial.is_none_or(|r| sp.policy.serial > r)
1334 
                        && sp.policy.serial < l.policy.serial
1335 
                })
1336 
                .collect();
1337 
        }
1338 
        let results = remote.push(
1339 
            bundle,
1340 
            vec![RefUpdate {
1341 
                name: bookmark.clone(),
1342 
                old_state: remote_state,
1343 
                new_state,
1344 
                force,
1345 
                attestation,
1346 
            }],
1347 
            policy_to_send,
1348 
            tags_to_send,
1349 
        )?;
1350 
        if let (Some(serial), true) = (
1351 
            sent_serial,
1352 
            results.iter().any(|r| r.ok && r.name == "policy"),
1353 
        ) {
1354 
            self.record_policy_serial(remote_name, serial)?;
1355 
        }
1356 
        if results.iter().any(|r| r.ok && r.name == bookmark) {
1357 
            let mut view = op.view.clone();
1358 
            view.remotes
1359 
                .entry(remote_name.to_string())
1360 
                .or_default()
1361 
                .insert(bookmark.clone(), new_state);
1362 
            self.record_op(&[op_ref], &format!("oxy push {remote_name}"), view)?;
1363 
            if let Some(s) = serial {
1364 
                self.record_serial(remote_name, &bookmark, s)?;
1365 
            }
1366 
        }
1367 
        Ok(results)
1368 
    }
1369
1370 
    /// Clone a remote into `dest`: same repository ID, `origin` remote,
1371 
    /// bookmark set to the remote's, working copy checked out.
1372 
    pub fn clone(url: &str, dest: &Path) -> Result<Repo> {
1373 
        Self::clone_with(url, dest, None, &[])
1374 
    }
1375
1376 
    /// Clone, leaving blobs above `max_blob` bytes to be fetched on first
1377 
    /// read, and materializing only `sparse` paths (which implies lazy blobs
1378 
    /// unless a size is given, so out-of-scope binaries are never fetched).
1379 
    pub fn clone_with(
1380 
        url: &str,
1381 
        dest: &Path,
1382 
        max_blob: Option<u64>,
1383 
        sparse: &[String],
1384 
    ) -> Result<Repo> {
1385 
        Self::clone_full(url, dest, max_blob, sparse, None)
1386 
    }
1387
1388 
    /// Shallow clone (spec §17): a checkpoint of the bookmark's heads plus the
1389 
    /// changes within `depth` steps of them; the rest is the boundary.
1390 
    pub fn clone_shallow(
1391 
        url: &str,
1392 
        dest: &Path,
1393 
        depth: u32,
1394 
        max_blob: Option<u64>,
1395 
        sparse: &[String],
1396 
    ) -> Result<Repo> {
1397 
        Self::clone_full(url, dest, max_blob, sparse, Some(depth))
1398 
    }
1399
1400 
    fn clone_full(
1401 
        url: &str,
1402 
        dest: &Path,
1403 
        max_blob: Option<u64>,
1404 
        sparse: &[String],
1405 
        depth: Option<u32>,
1406 
    ) -> Result<Repo> {
1407 
        let options = RemoteOptions {
1408 
            token: std::env::var("OXY_TOKEN").ok(),
1409 
            ca: std::env::var("OXY_CA").ok().map(PathBuf::from),
1410 
            repo_id: None,
1411 
        };
1412 
        let remote = open_remote(url, &options)?;
1413 
        let id = remote.repo_id()?;
1414 
        if id == crate::protocol::UNBOUND_ID {
1415 
            return fail(format!(
1416 
                "{url} is empty and unbound: push a repository to it first"
1417 
            ));
1418 
        }
1419 
        let mut repo = Repo::init_with_id(dest, id)?;
1420 
        repo.config.set("remote.origin.url", url)?;
1421 
        if let Some(m) = max_blob {
1422 
            repo.config.set("filter.max-blob", &m.to_string())?;
1423 
        } else if !sparse.is_empty() {
1424 
            repo.config.set("filter.max-blob", "0")?;
1425 
        }
1426 
        if !sparse.is_empty() {
1427 
            repo.config.set("filter.paths", &sparse.join(","))?;
1428 
        }
1429 
        repo.save_config()?;
1430 
        if let Some(depth) = depth {
1431 
            repo.fetch_shallow("origin", depth)?;
1432 
        } else {
1433 
            repo.fetch("origin")?;
1434 
        }
1435 
        let (op_ref, op) = repo.head_op()?;
1436 
        let bookmark = repo.config.bookmark.clone();
1437 
        if let Some(state) = op
1438 
            .view
1439 
            .remotes
1440 
            .get("origin")
1441 
            .and_then(|b| b.get(&bookmark))
1442 
            .copied()
1443 
        {
1444 
            let heads = repo.store.get_state(&state)?.heads;
1445 
            let mut view = op.view.clone();
1446 
            view.bookmarks.insert(bookmark, state);
1447 
            repo.record_op(&[op_ref], &format!("oxy clone {url}"), view)?;
1448 
            repo.checkout(&heads, false, "oxy clone (checkout)")?;
1449 
        }
1450 
        Ok(repo)
1451 
    }
1452 
}