OXYGENHUB
# be0161a88dd7 oxygen / crates / oxy-core / src / repo / sync.rs
53.3 KiB · Rust · last changed State is Send + Sync; shared lane layout; log_window 1 month ago source blame history raw
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//! Serving and talking to remotes (spec §10.2, §16).
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3 
use super::*;
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/// What a push did, for hosts (hub spec §6.12).
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#[derive(Clone, Debug, Default)]
7 
pub struct PushReport {
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    pub results: Vec<RefResult>,
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    /// Accepted reference updates, in request order.
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    pub updated: Vec<RefUpdated>,
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    /// Changes this push stored that were not already present.
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    pub imported: Vec<ChangeHash>,
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}
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#[derive(Clone, Debug)]
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pub struct RefUpdated {
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    pub name: String,
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    pub old_state: ObjectRef,
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    pub new_state: ObjectRef,
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    pub heads: Vec<ChangeHash>,
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}
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/// What a fetch brought in.
24 
#[derive(Debug, Clone, PartialEq, Eq, Default)]
25 
pub struct FetchReport {
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    /// Bookmark name, its heads, and how many changes were new.
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    pub refs: Vec<(String, Vec<ChangeHash>, usize)>,
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    /// Tags adopted from the remote.
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    pub new_tags: usize,
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    /// The remote has never presented a policy, so nothing was verified
31 
    /// against one (spec §14.5: warn loudly).
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    pub unverified: bool,
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}
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#[derive(Debug, Clone, PartialEq, Eq)]
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pub struct PullReport {
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    pub heads: Vec<ChangeHash>,
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    pub changed: bool,
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    pub checked_out: bool,
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}
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impl Repo {
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    // ------------------------------------------------------------ serving (spec §16)
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    fn ref_attest_path(&self, bookmark: &str) -> PathBuf {
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        self.oxy.join("attest").join(bookmark)
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    }
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    /// The latest reference attestation stored for a bookmark.
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    pub fn latest_ref_attest(&self, bookmark: &str) -> Result<Option<(ObjectRef, SignedAttest)>> {
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        match fs::read_to_string(self.ref_attest_path(bookmark)) {
52 
            Ok(h) => {
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                let r = ObjectRef::from_hex(h.trim())
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                    .ok_or_else(|| RepoError::Msg("corrupt attestation pointer".into()))?;
55 
                Ok(Some((
56 
                    r,
57 
                    SignedAttest {
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                        attest: self.store.get_attest(&r)?,
59 
                        sigs: self.store.signatures(&r)?,
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                    },
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                )))
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            }
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            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 
    }
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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 {
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                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 {
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                name: name.clone(),
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                state: *state,
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                heads: self.store.get_state(state)?.heads,
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                attestation,
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                last_serial,
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            });
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        }
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()
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                    .is_some_and(|p| sp.policy.serial < p.policy.serial)
99 
            })
100 
            .collect();
101 
        Ok(RefsResponse {
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            refs: out,
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            policy,
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            tags: self.tag_refs()?,
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            history,
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        })
107 
    }
108
109 
    /// Every change reachable from `heads` that is in the store.
110 
    fn closure_in_store(&self, heads: &[ChangeHash]) -> Result<BTreeSet<ChangeHash>> {
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        let mut seen = BTreeSet::new();
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        let mut stack: Vec<ChangeHash> = heads.to_vec();
113 
        while let Some(h) = stack.pop() {
114 
            if seen.contains(&h) || !self.store.has(&h) {
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                continue;
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            }
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            seen.insert(h);
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            stack.extend(self.store.get_change(&h)?.deps);
119 
        }
120 
        Ok(seen)
121 
    }
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    /// The changes within `depth` dependency steps of `heads` (spec §17),
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    /// nearest first; depth 1 is the heads themselves.
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    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() {
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                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 
    }
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152 
    /// The shallow boundary: dependencies this repository does not hold (spec §17).
153 
    pub fn boundary(&self) -> BTreeSet<ChangeHash> {
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        fs::read_to_string(self.shallow_path())
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            .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 
    fn check_ref_attest(
417 
        &self,
418 
        sa: &SignedAttest,
419 
        name: &str,
420 
        old_state: &ObjectRef,
421 
        new_state: &ObjectRef,
422 
        last_serial: Option<u64>,
423 
        allow_equal: bool,
424 
    ) -> std::result::Result<u64, String> {
425 
        let AttestBody::Ref {
426 
            name: n,
427 
            old_state: o,
428 
            new_state: nw,
429 
            serial,
430 
        } = &sa.attest.body
431 
        else {
432 
            return Err("attestation is not a ref attestation".into());
433 
        };
434 
        if n != name || o != old_state || nw != new_state {
435 
            return Err("attestation does not describe this update".into());
436 
        }
437 
        if sa.attest.repo != self.id().map_err(|e| e.to_string())? {
438 
            return Err("attestation is for a different repository".into());
439 
        }
440 
        if let Some(last) = last_serial {
441 
            if *serial < last || (*serial == last && !allow_equal) {
442 
                return Err(format!(
443 
                    "attestation serial {serial} is not greater than the last seen {last}"
444 
                ));
445 
            }
446 
        }
447 
        let r = sa.attest.hash();
448 
        let sig = sa.sigs.first().ok_or("attestation carries no signature")?;
449 
        let id = self
450 
            .store
451 
            .get_identity(&sig.key)
452 
            .map_err(|_| format!("unknown key {}", sig.key.short(12)))?;
453 
        verify_signature(&id, sig, Domain::Attest, &r).map_err(|e| e.to_string())?;
454 
        Ok(*serial)
455 
    }
456
457 
    /// Accept a push (spec §16.4). Without a trust policy every repository
458 
    /// is unverified, so unsigned changes and unattested updates are accepted;
459 
    /// attestations that are present must still be valid. With a policy,
460 
    /// every change and update is checked against it. A newer policy in the
461 
    /// push is applied first when it is signed by the current roots.
462 
    pub fn receive_push(
463 
        &self,
464 
        bundle: Bundle,
465 
        updates: Vec<RefUpdate>,
466 
        policy: Option<SignedPolicy>,
467 
        tags: Vec<crate::protocol::TagRef>,
468 
    ) -> Result<Vec<RefResult>> {
469 
        Ok(self
470 
            .receive_push_report(bundle, updates, policy, tags)?
471 
            .results)
472 
    }
473
474 
    /// `receive_push` with what a host wants to log: each accepted
475 
    /// reference's old and new state and heads, and the changes this push
476 
    /// stored (hub spec §6.12).
477 
    pub fn receive_push_report(
478 
        &self,
479 
        bundle: Bundle,
480 
        updates: Vec<RefUpdate>,
481 
        policy: Option<SignedPolicy>,
482 
        tags: Vec<crate::protocol::TagRef>,
483 
    ) -> Result<PushReport> {
484 
        let mut report = PushReport::default();
485 
        let results = &mut report.results;
486 
        if let Some(sp) = policy {
487 
            match self.adopt_policy_chain(&bundle.policies, &sp, "push received") {
488 
                Ok(()) => {
489 
                    results.push(RefResult {
490 
                        name: "policy".into(),
491 
                        ok: true,
492 
                        reason: format!("serial {}", sp.policy.serial),
493 
                    });
494 
                }
495 
                Err(e) => {
496 
                    results.push(RefResult {
497 
                        name: "policy".into(),
498 
                        ok: false,
499 
                        reason: e,
500 
                    });
501 
                    for u in updates {
502 
                        results.push(RefResult {
503 
                            name: u.name,
504 
                            ok: false,
505 
                            reason: "policy update was rejected".into(),
506 
                        });
507 
                    }
508 
                    return Ok(report);
509 
                }
510 
            }
511 
        }
512 
        let policy = self.current_policy()?.map(|(_, sp)| sp.policy);
513 
        match self.import_bundle(&bundle, policy.is_some()) {
514 
            Ok(imported) => report.imported = imported,
515 
            Err(e) => {
516 
                for u in updates {
517 
                    results.push(RefResult {
518 
                        name: u.name,
519 
                        ok: false,
520 
                        reason: e.to_string(),
521 
                    });
522 
                }
523 
                return Ok(report);
524 
            }
525 
        }
526 
        let (op_ref, op) = self.head_op()?;
527 
        let mut view = op.view.clone();
528 
        let mut names = Vec::new();
529 
        for u in updates {
530 
            let outcome = self.apply_update(&mut view, &u, policy.as_ref());
531 
            let (ok, reason) = match outcome {
532 
                Ok(()) => (true, String::new()),
533 
                Err(e) => (false, e),
534 
            };
535 
            if ok {
536 
                names.push(u.name.clone());
537 
                let heads = self
538 
                    .store
539 
                    .get_state(&u.new_state)
540 
                    .map(|s| s.heads)
541 
                    .unwrap_or_default();
542 
                report.updated.push(RefUpdated {
543 
                    name: u.name.clone(),
544 
                    old_state: u.old_state,
545 
                    new_state: u.new_state,
546 
                    heads,
547 
                });
548 
            }
549 
            results.push(RefResult {
550 
                name: u.name,
551 
                ok,
552 
                reason,
553 
            });
554 
        }
555 
        for t in &tags {
556 
            let name = format!("tags/{}", t.name);
557 
            match self.adopt_tag(&mut view, t, policy.as_ref()) {
558 
                Ok(()) => {
559 
                    names.push(name.clone());
560 
                    results.push(RefResult {
561 
                        name,
562 
                        ok: true,
563 
                        reason: String::new(),
564 
                    });
565 
                }
566 
                Err(e) => results.push(RefResult {
567 
                    name,
568 
                    ok: false,
569 
                    reason: e,
570 
                }),
571 
            }
572 
        }
573 
        if !names.is_empty() {
574 
            self.record_op(
575 
                &[op_ref],
576 
                &format!("push received: {}", names.join(" ")),
577 
                view,
578 
            )?;
579 
        }
580 
        Ok(report)
581 
    }
582
583 
    fn apply_update(
584 
        &self,
585 
        view: &mut View,
586 
        u: &RefUpdate,
587 
        policy: Option<&crate::policy::Policy>,
588 
    ) -> std::result::Result<(), String> {
589 
        if u.name == "policy" {
590 
            return Err(
591 
                "the policy reference is updated by sending a policy, not a bookmark update".into(),
592 
            );
593 
        }
594 
        let empty = self
595 
            .store
596 
            .put_state(&StateObject::new(vec![]))
597 
            .map_err(|e| e.to_string())?;
598 
        let current = view.bookmarks.get(&u.name).copied().unwrap_or(empty);
599 
        if current != u.old_state {
600 
            return Err("stale: the remote bookmark has moved; pull first".into());
601 
        }
602 
        let new_state = self
603 
            .store
604 
            .get_state(&u.new_state)
605 
            .map_err(|_| "new state object is missing".to_string())?;
606 
        for h in &new_state.heads {
607 
            if !self.store.has(h) {
608 
                return Err(format!("head {} is missing", h.short(12)));
609 
            }
610 
        }
611 
        if !u.force {
612 
            let old_heads = self
613 
                .store
614 
                .get_state(&current)
615 
                .map_err(|e| e.to_string())?
616 
                .heads;
617 
            let closure = self
618 
                .closure_in_store(&new_state.heads)
619 
                .map_err(|e| e.to_string())?;
620 
            if let Some(h) = old_heads.iter().find(|h| !closure.contains(h)) {
621 
                return Err(format!(
622 
                    "not a fast-forward: current head {} would be dropped (use --force)",
623 
                    h.short(12)
624 
                ));
625 
            }
626 
        }
627 
        if let Some(p) = policy {
628 
            let Some(sa) = &u.attestation else {
629 
                return Err(format!(
630 
                    "{:?} requires a signed reference attestation under this repository's policy",
631 
                    u.name
632 
                ));
633 
            };
634 
            let signer = sa
635 
                .sigs
636 
                .first()
637 
                .map(|s| s.key)
638 
                .ok_or("attestation carries no signature")?;
639 
            if !p.authorizes(&signer, &u.name) {
640 
                return Err(format!(
641 
                    "key {} may not update {:?} under this repository's policy",
642 
                    signer.short(12),
643 
                    u.name
644 
                ));
645 
            }
646 
            let old_heads = self
647 
                .store
648 
                .get_state(&current)
649 
                .map_err(|e| e.to_string())?
650 
                .heads;
651 
            self.state_allowed(&old_heads, &new_state.heads, p, &u.name)?;
652 
        }
653 
        if let Some(sa) = &u.attestation {
654 
            let last = self
655 
                .latest_ref_attest(&u.name)
656 
                .map_err(|e| e.to_string())?
657 
                .and_then(|(_, a)| match a.attest.body {
658 
                    AttestBody::Ref { serial, .. } => Some(serial),
659 
                    _ => None,
660 
                });
661 
            self.check_ref_attest(sa, &u.name, &u.old_state, &u.new_state, last, false)?;
662 
            let r = self
663 
                .store
664 
                .put_attest(&sa.attest)
665 
                .map_err(|e| e.to_string())?;
666 
            for sig in &sa.sigs {
667 
                self.store
668 
                    .put_signature(&r, sig)
669 
                    .map_err(|e| e.to_string())?;
670 
            }
671 
            self.set_ref_attest(&u.name, &r)
672 
                .map_err(|e| e.to_string())?;
673 
        }
674 
        view.bookmarks.insert(u.name.clone(), u.new_state);
675 
        Ok(())
676 
    }
677
678 
    // ------------------------------------------------------------ client side
679
680 
    fn remote_url(&self, name: &str) -> Result<String> {
681 
        self.config.remotes.get(name).cloned().ok_or_else(|| {
682 
            RepoError::Msg(format!(
683 
                "no remote named {name:?}; add one with `oxy remote add`"
684 
            ))
685 
        })
686 
    }
687
688 
    /// Credentials and trust for a remote: `remote.<name>.token` (else
689 
    /// `$OXY_TOKEN`) and `remote.<name>.ca` (else `$OXY_CA`).
690 
    /// Refuse a remote that is another repository. An **unbound** remote
691 
    /// (id all zero: a hosted repository nobody has pushed to) is accepted
692 
    /// for pushes, which bind it to this repository's id (spec §16.1).
693 
    fn check_remote_id(
694 
        &self,
695 
        remote: &dyn crate::protocol::Remote,
696 
        remote_name: &str,
697 
        allow_unbound: bool,
698 
    ) -> Result<()> {
699 
        let theirs = remote.repo_id()?;
700 
        if theirs == self.id()? {
701 
            return Ok(());
702 
        }
703 
        if theirs == crate::protocol::UNBOUND_ID {
704 
            if allow_unbound {
705 
                return Ok(());
706 
            }
707 
            return fail(format!(
708 
                "remote {remote_name:?} is empty and unbound: push to it first"
709 
            ));
710 
        }
711 
        fail(format!(
712 
            "remote {remote_name:?} is a different repository (repository IDs differ)"
713 
        ))
714 
    }
715
716 
    fn remote_options(&self, name: &str) -> RemoteOptions {
717 
        RemoteOptions {
718 
            repo_id: self.id().ok(),
719 
            token: self
720 
                .config
721 
                .remote_tokens
722 
                .get(name)
723 
                .cloned()
724 
                .or_else(|| std::env::var("OXY_TOKEN").ok()),
725 
            ca: self
726 
                .config
727 
                .remote_cas
728 
                .get(name)
729 
                .map(PathBuf::from)
730 
                .or_else(|| std::env::var("OXY_CA").ok().map(PathBuf::from)),
731 
        }
732 
    }
733
734 
    fn open_named_remote(&self, name: &str) -> Result<Box<dyn crate::protocol::Remote>> {
735 
        open_remote(&self.remote_url(name)?, &self.remote_options(name))
736 
    }
737
738 
    fn serial_path(&self, remote: &str, bookmark: &str) -> PathBuf {
739 
        self.oxy
740 
            .join("remotes")
741 
            .join(remote)
742 
            .join(format!("{bookmark}.serial"))
743 
    }
744
745 
    fn last_seen_serial(&self, remote: &str, bookmark: &str) -> Option<u64> {
746 
        fs::read_to_string(self.serial_path(remote, bookmark))
747 
            .ok()
748 
            .and_then(|s| s.trim().parse().ok())
749 
    }
750
751 
    fn record_serial(&self, remote: &str, bookmark: &str, serial: u64) -> Result<()> {
752 
        let p = self.serial_path(remote, bookmark);
753 
        fs::create_dir_all(p.parent().unwrap())?;
754 
        write_atomic(&p, serial.to_string().as_bytes())
755 
    }
756
757 
    fn policy_serial_path(&self, remote: &str) -> PathBuf {
758 
        self.oxy.join("remotes").join(remote).join("policy.serial")
759 
    }
760
761 
    /// The highest policy serial `remote` has ever presented.
762 
    fn remote_policy_serial(&self, remote: &str) -> Option<u64> {
763 
        fs::read_to_string(self.policy_serial_path(remote))
764 
            .ok()
765 
            .and_then(|s| s.trim().parse().ok())
766 
    }
767
768 
    fn record_policy_serial(&self, remote: &str, serial: u64) -> Result<()> {
769 
        let p = self.policy_serial_path(remote);
770 
        fs::create_dir_all(p.parent().unwrap())?;
771 
        write_atomic(&p, serial.to_string().as_bytes())
772 
    }
773
774 
    fn lazy_dir(&self) -> PathBuf {
775 
        self.oxy.join("lazy")
776 
    }
777
778 
    /// Remember that `blob` was withheld by `remote` (spec §13.5).
779 
    fn register_lazy(&self, blob: &ObjectRef, remote: &str) -> Result<()> {
780 
        fs::create_dir_all(self.lazy_dir())?;
781 
        write_atomic(&self.lazy_dir().join(blob.to_hex()), remote.as_bytes())
782 
    }
783
784 
    /// Which remote promised an absent blob, if any.
785 
    pub fn lazy_remote(&self, blob: &ObjectRef) -> Option<String> {
786 
        fs::read_to_string(self.lazy_dir().join(blob.to_hex()))
787 
            .ok()
788 
            .map(|s| s.trim().to_string())
789 
    }
790
791 
    /// Fetch an absent blob (and its chunks) from the remote that promised it.
792 
    pub(crate) fn fetch_lazy_blob(&self, blob: &ObjectRef) -> Result<()> {
793 
        let Some(remote_name) = self.lazy_remote(blob) else {
794 
            return Err(RepoError::Store(StoreError::NotFound(*blob)));
795 
        };
796 
        let remote = self.open_named_remote(&remote_name)?;
797 
        let objects = remote.objects(&[*blob])?;
798 
        for (ty, body) in objects {
799 
            if matches!(ty, ObjectType::Blob | ObjectType::Chunk) {
800 
                self.store.put(ty, &body)?;
801 
            }
802 
        }
803 
        if !self.store.has(blob) {
804 
            return fail(format!(
805 
                "{remote_name} did not send blob {}",
806 
                blob.short(12)
807 
            ));
808 
        }
809 
        let _ = fs::remove_file(self.lazy_dir().join(blob.to_hex()));
810 
        Ok(())
811 
    }
812
813 
    /// After importing from `remote`, record every blob the changes reference
814 
    /// that the store lacks as lazily available from that remote.
815 
    fn register_missing_blobs(&self, changes: &[ChangeHash], remote: &str) -> Result<usize> {
816 
        let mut n = 0;
817 
        for h in changes {
818 
            let c = self.store.get_change(h)?;
819 
            for e in &c.edits {
820 
                if let Edit::Replace { old, new, .. } = e {
821 
                    for b in [old, new].into_iter().flatten() {
822 
                        if !self.store.has(b) {
823 
                            self.register_lazy(b, remote)?;
824 
                            n += 1;
825 
                        }
826 
                    }
827 
                }
828 
            }
829 
        }
830 
        Ok(n)
831 
    }
832
833 
    /// Every head this repository knows: bookmarks, remote tracking, working copy.
834 
    fn known_heads(&self, view: &View) -> Result<Vec<ChangeHash>> {
835 
        let mut have: BTreeSet<ChangeHash> = BTreeSet::new();
836 
        for st in view
837 
            .bookmarks
838 
            .values()
839 
            .chain(view.remotes.values().flat_map(|b| b.values()))
840 
        {
841 
            if let Ok(s) = self.store.get_state(st) {
842 
                have.extend(s.heads);
843 
            }
844 
        }
845 
        have.extend(view.workspaces.values().copied());
846 
        Ok(have.into_iter().collect())
847 
    }
848
849 
    /// Fetch every bookmark of a remote into `remotes/<name>/bookmarks/*` (spec §10.2).
850 
    pub fn fetch(&self, remote_name: &str) -> Result<FetchReport> {
851 
        let remote = self.open_named_remote(remote_name)?;
852 
        self.check_remote_id(remote.as_ref(), remote_name, false)?;
853 
        let resp = remote.refs()?;
854 
        // Trust policy (spec §14.5). Adopt the remote's policy when it is newer
855 
        // and signed by roots we trust, or on first contact. A remote that
856 
        // once presented a policy may never present none or an older one:
857 
        // that is a downgrade. A remote that never presented one is
858 
        // unverified, and this fetch is checked only as far as possible.
859 
        let local_policy = self.current_policy()?.map(|(_, sp)| sp.policy);
860 
        let seen = self.remote_policy_serial(remote_name);
861 
        let mut unverified = false;
862 
        match &resp.policy {
863 
            Some(sp) => {
864 
                if seen.is_some_and(|s| sp.policy.serial < s) {
865 
                    return fail(format!("{remote_name} presents policy serial {} but presented {} before: refusing the downgrade", sp.policy.serial, seen.unwrap()));
866 
                }
867 
                match &local_policy {
868 
                    Some(l) if sp.policy.serial < l.serial => {}
869 
                    Some(l) if sp.policy.serial == l.serial => {
870 
                        if sp.policy.hash() != l.hash() {
871 
                            return fail(format!(
872 
                                "{remote_name} presents a different policy with the same serial {}",
873 
                                l.serial
874 
                            ));
875 
                        }
876 
                    }
877 
                    _ => {
878 
                        self.adopt_policy_chain(
879 
                            &resp.history,
880 
                            sp,
881 
                            &format!("oxy fetch {remote_name}"),
882 
                        )
883 
                        .map_err(|e| RepoError::Msg(format!("policy from {remote_name}: {e}")))?;
884 
                    }
885 
                }
886 
                self.record_policy_serial(remote_name, sp.policy.serial)?;
887 
            }
888 
            None => {
889 
                if seen.is_some() {
890 
                    return fail(format!("{remote_name} presented a policy before but has none now: refusing the downgrade"));
891 
                }
892 
                unverified = true;
893 
            }
894 
        }
895 
        let policy = if unverified {
896 
            None
897 
        } else {
898 
            self.current_policy()?.map(|(_, sp)| sp.policy)
899 
        };
900 
        let (op_ref, op) = self.head_op()?;
901 
        let mut view = op.view.clone();
902 
        let have = self.known_heads(&view)?;
903 
        let mut report = Vec::new();
904 
        let max_blob = self.config.max_blob;
905 
        for r in resp.refs {
906 
            let needed = remote.negotiate(&have, &r.heads)?;
907 
            let bundle = remote.fetch(&needed, max_blob)?;
908 
            // Changes are not individually re-verified here: the bookmark's
909 
            // attestation (checked below) binds its whole state, and the
910 
            // receiver of the push verified the added changes at that time.
911 
            let imported = self.import_bundle(&bundle, false)?;
912 
            if max_blob.is_some() {
913 
                self.register_missing_blobs(&imported, remote_name)?;
914 
            }
915 
            for h in &r.heads {
916 
                if !self.store.has(h) {
917 
                    return fail(format!("remote did not send head {}", h.short(12)));
918 
                }
919 
            }
920 
            let state = self.store.put_state(&StateObject::new(r.heads.clone()))?;
921 
            if state != r.state {
922 
                return fail(format!(
923 
                    "remote state {} does not match its heads",
924 
                    r.state.short(12)
925 
                ));
926 
            }
927 
            if let Some(p) = &policy {
928 
                let Some(sa) = &r.attestation else {
929 
                    return fail(format!(
930 
                        "{remote_name}/{} has no attestation, which its policy requires",
931 
                        r.name
932 
                    ));
933 
                };
934 
                let signer = sa
935 
                    .sigs
936 
                    .first()
937 
                    .map(|s| s.key)
938 
                    .ok_or_else(|| RepoError::Msg("attestation carries no signature".into()))?;
939 
                if !p.authorizes(&signer, &r.name) {
940 
                    return fail(format!(
941 
                        "{remote_name}/{}: attested by {}, which the policy does not authorize",
942 
                        r.name,
943 
                        signer.short(12)
944 
                    ));
945 
                }
946 
            }
947 
            if let Some(sa) = &r.attestation {
948 
                let AttestBody::Ref {
949 
                    old_state,
950 
                    new_state,
951 
                    ..
952 
                } = &sa.attest.body
953 
                else {
954 
                    return fail("remote sent a non-ref attestation for a bookmark");
955 
                };
956 
                let (old_state, new_state) = (*old_state, *new_state);
957 
                let serial = self
958 
                    .check_ref_attest(
959 
                        sa,
960 
                        &r.name,
961 
                        &old_state,
962 
                        &new_state,
963 
                        self.last_seen_serial(remote_name, &r.name),
964 
                        true,
965 
                    )
966 
                    .map_err(|e| {
967 
                        RepoError::Msg(format!("attestation for {}/{}: {e}", remote_name, r.name))
968 
                    })?;
969 
                if new_state != r.state {
970 
                    return fail(format!(
971 
                        "attestation for {}/{} does not cover its current state",
972 
                        remote_name, r.name
973 
                    ));
974 
                }
975 
                let ar = self.store.put_attest(&sa.attest)?;
976 
                for sig in &sa.sigs {
977 
                    self.store.put_signature(&ar, sig)?;
978 
                }
979 
                self.record_serial(remote_name, &r.name, serial)?;
980 
            }
981 
            view.remotes
982 
                .entry(remote_name.to_string())
983 
                .or_default()
984 
                .insert(r.name.clone(), state);
985 
            report.push((r.name, r.heads, imported.len()));
986 
        }
987 
        let mut new_tags = 0;
988 
        for t in &resp.tags {
989 
            if view.tags.contains_key(&t.name) {
990 
                continue;
991 
            }
992 
            // The tag's changes must be here: fetch them if the bookmarks did not bring them.
993 
            let missing: Vec<ChangeHash> = t
994 
                .heads
995 
                .iter()
996 
                .filter(|h| !self.store.has(h))
997 
                .copied()
998 
                .collect();
999 
            if !missing.is_empty() {
1000 
                let needed = remote.negotiate(&self.known_heads(&view)?, &missing)?;
1001 
                let bundle = remote.fetch(&needed, max_blob)?;
1002 
                self.import_bundle(&bundle, false)?;
1003 
            }
1004 
            self.store.put_state(&StateObject::new(t.heads.clone()))?;
1005 
            self.adopt_tag(&mut view, t, policy.as_ref())
1006 
                .map_err(|e| RepoError::Msg(format!("{remote_name} {}: {e}", t.name)))?;
1007 
            new_tags += 1;
1008 
        }
1009 
        if view != op.view {
1010 
            self.record_op(&[op_ref], &format!("oxy fetch {remote_name}"), view)?;
1011 
        }
1012 
        let _ = self.run_hook(
1013 
            "post-fetch",
1014 
            &format!(
1015 
                "{{\"event\":\"post-fetch\",\"remote\":{},\"bookmarks\":{}}}",
1016 
                json_str(remote_name),
1017 
                json_array(report.iter().map(|(n, heads, _)| format!(
1018 
                    "{{\"name\":{},\"heads\":{}}}",
1019 
                    json_str(n),
1020 
                    json_array(heads.iter().map(|h| json_str(&h.to_hex())))
1021 
                )))
1022 
            ),
1023 
        );
1024 
        Ok(FetchReport {
1025 
            refs: report,
1026 
            unverified,
1027 
            new_tags,
1028 
        })
1029 
    }
1030
1031 
    /// Shallow fetch of the remote's bookmark: its checkpoint as our base,
1032 
    /// the changes within `depth` steps of its heads, and the boundary below.
1033 
    pub fn fetch_shallow(&self, remote_name: &str, depth: u32) -> Result<usize> {
1034 
        let remote = self.open_named_remote(remote_name)?;
1035 
        self.check_remote_id(remote.as_ref(), remote_name, false)?;
1036 
        let resp = remote.refs()?;
1037 
        let bookmark = self.config.bookmark.clone();
1038 
        if let Some(sp) = &resp.policy {
1039 
            self.adopt_policy_chain(&resp.history, sp, "oxy clone --depth")
1040 
                .map_err(|e| RepoError::Msg(format!("policy from {remote_name}: {e}")))?;
1041 
            self.record_policy_serial(remote_name, sp.policy.serial)?;
1042 
        }
1043 
        let Some(r) = resp.refs.into_iter().find(|r| r.name == bookmark) else {
1044 
            return fail(format!("{remote_name} has no bookmark {bookmark:?}"));
1045 
        };
1046 
        if r.heads.is_empty() {
1047 
            return Ok(0);
1048 
        }
1049 
        // Base: the remote's checkpoint of exactly these heads.
1050 
        let cp_bundle = remote.checkpoint(&r.heads)?;
1051 
        let mut cp_ref = None;
1052 
        for (ty, body) in &cp_bundle.objects {
1053 
            let put = self.store.put(*ty, body)?;
1054 
            if *ty == ObjectType::Checkpoint {
1055 
                cp_ref = Some(put);
1056 
            }
1057 
        }
1058 
        let Some(cp_ref) = cp_ref else {
1059 
            return fail(format!("{remote_name} sent no checkpoint"));
1060 
        };
1061 
        self.install_checkpoint(&bookmark, &cp_ref)?;
1062 
        // History window.
1063 
        let wanted = remote.shallow(&r.heads, depth)?;
1064 
        let bundle = remote.fetch(&wanted, self.config.max_blob)?;
1065 
        let imported = self.import_bundle_shallow(&bundle, false)?;
1066 
        if self.config.max_blob.is_some() {
1067 
            self.register_missing_blobs(&imported, remote_name)?;
1068 
        }
1069 
        self.refresh_boundary(&imported)?;
1070 
        if let Some(sa) = &r.attestation {
1071 
            let ar = self.store.put_attest(&sa.attest)?;
1072 
            for sig in &sa.sigs {
1073 
                self.store.put_signature(&ar, sig)?;
1074 
            }
1075 
            if let AttestBody::Ref { serial, .. } = sa.attest.body {
1076 
                self.record_serial(remote_name, &r.name, serial)?;
1077 
            }
1078 
        }
1079 
        let state = self.store.put_state(&StateObject::new(r.heads.clone()))?;
1080 
        let (op_ref, op) = self.head_op()?;
1081 
        let mut view = op.view.clone();
1082 
        view.remotes
1083 
            .entry(remote_name.to_string())
1084 
            .or_default()
1085 
            .insert(r.name.clone(), state);
1086 
        self.record_op(
1087 
            &[op_ref],
1088 
            &format!("oxy fetch {remote_name} --depth {depth}"),
1089 
            view,
1090 
        )?;
1091 
        Ok(imported.len())
1092 
    }
1093
1094 
    /// Fetch, then take the union of the local bookmark's state with the
1095 
    /// remote's: no merge change, conflicts become reified (spec §9.4).
1096 
    pub fn pull(&self, remote_name: &str) -> Result<PullReport> {
1097 
        self.fetch(remote_name)?;
1098 
        let (op_ref, op) = self.head_op()?;
1099 
        let bookmark = self.config.bookmark.clone();
1100 
        let local = self.heads_of(&op.view, &bookmark)?;
1101 
        let Some(remote_state) = op
1102 
            .view
1103 
            .remotes
1104 
            .get(remote_name)
1105 
            .and_then(|b| b.get(&bookmark))
1106 
            .copied()
1107 
        else {
1108 
            return Ok(PullReport {
1109 
                heads: local,
1110 
                changed: false,
1111 
                checked_out: false,
1112 
            });
1113 
        };
1114 
        let remote_heads = self.store.get_state(&remote_state)?.heads;
1115 
        let mut all = local.clone();
1116 
        all.extend(remote_heads);
1117 
        let st = self.load_state(&all)?;
1118 
        let mut heads = st.maximal(&all);
1119 
        heads.sort();
1120 
        let mut sorted_local = local.clone();
1121 
        sorted_local.sort();
1122 
        if heads == sorted_local {
1123 
            return Ok(PullReport {
1124 
                heads,
1125 
                changed: false,
1126 
                checked_out: false,
1127 
            });
1128 
        }
1129 
        let mut view = op.view.clone();
1130 
        view.bookmarks.insert(
1131 
            bookmark.clone(),
1132 
            self.store.put_state(&StateObject::new(heads.clone()))?,
1133 
        );
1134 
        self.record_op(&[op_ref], &format!("oxy pull {remote_name}"), view)?;
1135 
        // Follow along if the working copy was clean and on the old heads.
1136 
        let snap = self.snapshot("oxy pull")?;
1137 
        let clean = snap.wc.tree_ops.is_empty() && snap.wc.edits.is_empty();
1138 
        let mut base = snap.base.maximal(&snap.wc.deps);
1139 
        base.sort();
1140 
        let mut checked_out = false;
1141 
        if clean && base == sorted_local {
1142 
            self.checkout(&heads, false, "oxy pull (checkout)")?;
1143 
            checked_out = true;
1144 
        }
1145 
        Ok(PullReport {
1146 
            heads,
1147 
            changed: true,
1148 
            checked_out,
1149 
        })
1150 
    }
1151
1152 
    /// Push the current bookmark (spec §16.3), sealing this author's unsigned
1153 
    /// changes and attesting the reference when a key is available.
1154 
    pub fn push(&self, remote_name: &str, force: bool) -> Result<Vec<RefResult>> {
1155 
        let bookmark = self.config.bookmark.clone();
1156 
        self.push_bookmark(remote_name, &bookmark, force)
1157 
    }
1158
1159 
    /// `push` for a named bookmark (`oxy push -b NAME`).
1160 
    pub fn push_bookmark(
1161 
        &self,
1162 
        remote_name: &str,
1163 
        bookmark: &str,
1164 
        force: bool,
1165 
    ) -> Result<Vec<RefResult>> {
1166 
        let (op_ref, op) = self.head_op()?;
1167 
        if !op.view.bookmarks.contains_key(bookmark) {
1168 
            return fail(format!("no bookmark {bookmark}"));
1169 
        }
1170 
        let bookmark = bookmark.to_string();
1171 
        let local_heads = self.heads_of(&op.view, &bookmark)?;
1172 
        // pre-push hook: may veto before the remote is contacted.
1173 
        self.run_hook(
1174 
            "pre-push",
1175 
            &format!(
1176 
                "{{\"event\":\"pre-push\",\"remote\":{},\"bookmark\":{},\"heads\":{}}}",
1177 
                json_str(remote_name),
1178 
                json_str(&bookmark),
1179 
                json_array(local_heads.iter().map(|h| json_str(&h.to_hex())))
1180 
            ),
1181 
        )?;
1182 
        let remote = self.open_named_remote(remote_name)?;
1183 
        self.check_remote_id(remote.as_ref(), remote_name, true)?;
1184 
        let resp = remote.refs()?;
1185 
        let local_policy = self.current_policy()?.map(|(_, sp)| sp);
1186 
        let resp_policy_serial = resp.policy.as_ref().map(|p| p.policy.serial);
1187 
        let policy_to_send = match (&local_policy, &resp.policy) {
1188 
            (Some(l), Some(r)) if l.policy.serial > r.policy.serial => Some(l.clone()),
1189 
            (Some(l), None) => Some(l.clone()),
1190 
            (Some(l), Some(r)) if l.policy.serial < r.policy.serial => {
1191 
                return fail(format!(
1192 
                    "{remote_name} has a newer policy (serial {}); fetch first",
1193 
                    r.policy.serial
1194 
                ));
1195 
            }
1196 
            _ => None,
1197 
        };
1198 
        let remote_has_policy = resp.policy.is_some() || policy_to_send.is_some();
1199 
        if remote_has_policy && self.secret_key()?.is_none() {
1200 
            return fail(format!("{remote_name} enforces a trust policy; pushing needs an identity (`oxy identity create`)"));
1201 
        }
1202 
        let remote_tags: BTreeSet<String> = resp.tags.iter().map(|t| t.name.clone()).collect();
1203 
        let tags_to_send: Vec<crate::protocol::TagRef> = self
1204 
            .tag_refs()?
1205 
            .into_iter()
1206 
            .filter(|t| !remote_tags.contains(&t.name))
1207 
            .collect();
1208 
        let refs = resp.refs;
1209 
        let empty = self.store.put_state(&StateObject::new(vec![]))?;
1210 
        let (remote_state, remote_heads, last_serial) =
1211 
            match refs.iter().find(|r| r.name == bookmark) {
1212 
                Some(r) => (r.state, r.heads.clone(), r.last_serial),
1213 
                None => (empty, vec![], None),
1214 
            };
1215 
        let new_state = self
1216 
            .store
1217 
            .put_state(&StateObject::new(local_heads.clone()))?;
1218 
        // A push that carries a policy re-attests the bookmark even when its
1219 
        // state is unchanged, so the current attestation is always by a key
1220 
        // the current policy authorizes (a revoked key's attestation would
1221 
        // otherwise be refused by every later fetch).
1222 
        if new_state == remote_state && policy_to_send.is_none() && tags_to_send.is_empty() {
1223 
            return Ok(vec![RefResult {
1224 
                name: bookmark,
1225 
                ok: true,
1226 
                reason: "already up to date".into(),
1227 
            }]);
1228 
        }
1229 
        for h in &remote_heads {
1230 
            if !self.store.has(h) {
1231 
                return fail(format!(
1232 
                    "the remote has change {} which you do not; pull first",
1233 
                    h.short(12)
1234 
                ));
1235 
            }
1236 
        }
1237 
        if !force {
1238 
            let closure = self.closure_in_store(&local_heads)?;
1239 
            if let Some(h) = remote_heads.iter().find(|h| !closure.contains(h)) {
1240 
                return fail(format!("not a fast-forward: remote head {} is not in your state; pull first or use --force", h.short(12)));
1241 
            }
1242 
        }
1243 
        let to_send = self.negotiate(&remote_heads, &local_heads)?;
1244 
        let mut bundle = self.bundle_for(&to_send)?;
1245 
        let key = self.secret_key()?.map(|(k, _)| k);
1246 
        if let Some(key) = key {
1247 
            // Seal this author's changes that carry no valid authenticator,
1248 
            // and adopt anonymous ones (zero author, spec §14.4).
1249 
            let mut unsigned = Vec::new();
1250 
            for h in &to_send {
1251 
                let c = self.store.get_change(h)?;
1252 
                if (c.author == key || c.author.is_zero())
1253 
                    && !matches!(self.authenticate_change(h)?, SignatureStatus::Valid { .. })
1254 
                {
1255 
                    unsigned.push(*h);
1256 
                }
1257 
            }
1258 
            for chunk in unsigned.chunks(crate::attest::MAX_SEAL_HASHES) {
1259 
                let sa = self.sign_attest(&Attest::seal(self.id()?, chunk.to_vec()))?;
1260 
                bundle.attests.push(sa);
1261 
            }
1262 
            bundle = self.bundle_for(&to_send)?;
1263 
        }
1264 
        bundle.objects.push((
1265 
            ObjectType::State,
1266 
            StateObject::new(local_heads.clone()).encode(),
1267 
        ));
1268 
        let attestation = match key {
1269 
            Some(_) => Some(self.sign_attest(&Attest {
1270 
                repo: self.id()?,
1271 
                hlc: Hlc::now(),
1272 
                body: AttestBody::Ref {
1273 
                    name: bookmark.clone(),
1274 
                    old_state: remote_state,
1275 
                    new_state,
1276 
                    serial: last_serial.unwrap_or(0) + 1,
1277 
                },
1278 
            })?),
1279 
            None => None,
1280 
        };
1281 
        let serial = attestation.as_ref().and_then(|a| match a.attest.body {
1282 
            AttestBody::Ref { serial, .. } => Some(serial),
1283 
            _ => None,
1284 
        });
1285 
        let sent_serial = policy_to_send.as_ref().map(|p| p.policy.serial);
1286 
        // Tag states must be present on the remote: bundle their changes too.
1287 
        for t in &tags_to_send {
1288 
            let extra = self.negotiate(&remote_heads, &t.heads)?;
1289 
            let extra: Vec<ChangeHash> =
1290 
                extra.into_iter().filter(|h| !to_send.contains(h)).collect();
1291 
            if !extra.is_empty() {
1292 
                let more = self.bundle_for(&extra)?;
1293 
                bundle.changes.extend(more.changes);
1294 
                bundle.attests.extend(more.attests);
1295 
                bundle.objects.extend(more.objects);
1296 
            }
1297 
            bundle.objects.push((
1298 
                ObjectType::State,
1299 
                StateObject::new(t.heads.clone()).encode(),
1300 
            ));
1301 
        }
1302 
        if let Some(l) = &policy_to_send {
1303 
            let remote_serial = resp_policy_serial;
1304 
            bundle.policies = self
1305 
                .policy_history()?
1306 
                .into_iter()
1307 
                .filter(|sp| {
1308 
                    remote_serial.is_none_or(|r| sp.policy.serial > r)
1309 
                        && sp.policy.serial < l.policy.serial
1310 
                })
1311 
                .collect();
1312 
        }
1313 
        let results = remote.push(
1314 
            bundle,
1315 
            vec![RefUpdate {
1316 
                name: bookmark.clone(),
1317 
                old_state: remote_state,
1318 
                new_state,
1319 
                force,
1320 
                attestation,
1321 
            }],
1322 
            policy_to_send,
1323 
            tags_to_send,
1324 
        )?;
1325 
        if let (Some(serial), true) = (
1326 
            sent_serial,
1327 
            results.iter().any(|r| r.ok && r.name == "policy"),
1328 
        ) {
1329 
            self.record_policy_serial(remote_name, serial)?;
1330 
        }
1331 
        if results.iter().any(|r| r.ok && r.name == bookmark) {
1332 
            let mut view = op.view.clone();
1333 
            view.remotes
1334 
                .entry(remote_name.to_string())
1335 
                .or_default()
1336 
                .insert(bookmark.clone(), new_state);
1337 
            self.record_op(&[op_ref], &format!("oxy push {remote_name}"), view)?;
1338 
            if let Some(s) = serial {
1339 
                self.record_serial(remote_name, &bookmark, s)?;
1340 
            }
1341 
        }
1342 
        Ok(results)
1343 
    }
1344
1345 
    /// Clone a remote into `dest`: same repository ID, `origin` remote,
1346 
    /// bookmark set to the remote's, working copy checked out.
1347 
    pub fn clone(url: &str, dest: &Path) -> Result<Repo> {
1348 
        Self::clone_with(url, dest, None, &[])
1349 
    }
1350
1351 
    /// Clone, leaving blobs above `max_blob` bytes to be fetched on first
1352 
    /// read, and materializing only `sparse` paths (which implies lazy blobs
1353 
    /// unless a size is given, so out-of-scope binaries are never fetched).
1354 
    pub fn clone_with(
1355 
        url: &str,
1356 
        dest: &Path,
1357 
        max_blob: Option<u64>,
1358 
        sparse: &[String],
1359 
    ) -> Result<Repo> {
1360 
        Self::clone_full(url, dest, max_blob, sparse, None)
1361 
    }
1362
1363 
    /// Shallow clone (spec §17): a checkpoint of the bookmark's heads plus the
1364 
    /// changes within `depth` steps of them; the rest is the boundary.
1365 
    pub fn clone_shallow(
1366 
        url: &str,
1367 
        dest: &Path,
1368 
        depth: u32,
1369 
        max_blob: Option<u64>,
1370 
        sparse: &[String],
1371 
    ) -> Result<Repo> {
1372 
        Self::clone_full(url, dest, max_blob, sparse, Some(depth))
1373 
    }
1374
1375 
    fn clone_full(
1376 
        url: &str,
1377 
        dest: &Path,
1378 
        max_blob: Option<u64>,
1379 
        sparse: &[String],
1380 
        depth: Option<u32>,
1381 
    ) -> Result<Repo> {
1382 
        let options = RemoteOptions {
1383 
            token: std::env::var("OXY_TOKEN").ok(),
1384 
            ca: std::env::var("OXY_CA").ok().map(PathBuf::from),
1385 
            repo_id: None,
1386 
        };
1387 
        let remote = open_remote(url, &options)?;
1388 
        let id = remote.repo_id()?;
1389 
        if id == crate::protocol::UNBOUND_ID {
1390 
            return fail(format!(
1391 
                "{url} is empty and unbound: push a repository to it first"
1392 
            ));
1393 
        }
1394 
        let mut repo = Repo::init_with_id(dest, id)?;
1395 
        repo.config.set("remote.origin.url", url)?;
1396 
        if let Some(m) = max_blob {
1397 
            repo.config.set("filter.max-blob", &m.to_string())?;
1398 
        } else if !sparse.is_empty() {
1399 
            repo.config.set("filter.max-blob", "0")?;
1400 
        }
1401 
        if !sparse.is_empty() {
1402 
            repo.config.set("filter.paths", &sparse.join(","))?;
1403 
        }
1404 
        repo.save_config()?;
1405 
        if let Some(depth) = depth {
1406 
            repo.fetch_shallow("origin", depth)?;
1407 
        } else {
1408 
            repo.fetch("origin")?;
1409 
        }
1410 
        let (op_ref, op) = repo.head_op()?;
1411 
        let bookmark = repo.config.bookmark.clone();
1412 
        if let Some(state) = op
1413 
            .view
1414 
            .remotes
1415 
            .get("origin")
1416 
            .and_then(|b| b.get(&bookmark))
1417 
            .copied()
1418 
        {
1419 
            let heads = repo.store.get_state(&state)?.heads;
1420 
            let mut view = op.view.clone();
1421 
            view.bookmarks.insert(bookmark, state);
1422 
            repo.record_op(&[op_ref], &format!("oxy clone {url}"), view)?;
1423 
            repo.checkout(&heads, false, "oxy clone (checkout)")?;
1424 
        }
1425 
        Ok(repo)
1426 
    }
1427 
}