fix(git-remote): stop waiting on EOF for a delete-only push - #442
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Included review availability: 3 reviews are currently available. Your included PR review attempts over the past 7 days set your current allowance at 5 reviews per hour. 📝 WalkthroughWalkthroughReceive-pack handling now supports push certificates, push-options, and pack data framing. Tests cover signed pushes and real delete-only pushes. The integration test verifies bounded completion and remote branch deletion. ChangesReceive-pack delete handling
Priority: ➖ Normal Estimated code review effort: 4 (Complex) | ~45 minutes Change: Bug fix · Severity of issue fixed: Medium Merge Risk: ⚪ Minimal · up to The receive-pack framing change has no unresolved merge-blocking risk. 🚥 Pre-merge checks | ✅ 5✅ Passed checks (5 passed)
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Greptile SummaryThis PR changes receive-pack request framing so delete-only pushes stop at the protocol boundary rather than waiting for pipe EOF, and extends the integration shim to exercise deletion through real Git.
Confidence Score: 4/5The PR is not yet safe to merge because signed pushes carrying push options can fail or deadlock. The previous certificate-framing finding is fixed for pushes negotiating only a certificate. However, the new handling consumes push options before the certificate when both are negotiated, allowing the options parser to absorb both sections and leaving the certificate parser to reject PACK bytes or wait indefinitely. Files Needing Attention: crates/git-remote-gitlawb/src/main.rs
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| Filename | Overview |
|---|---|
| crates/git-remote-gitlawb/src/main.rs | Reframes receive-pack input around pkt-line boundaries, but parses co-negotiated push certificates and push options in reverse protocol order. |
| crates/git-remote-gitlawb/tests/real_git_fetch.rs | Extends the HTTP shim with receive-pack support and adds an end-to-end delete-only push regression test. |
Sequence Diagram
sequenceDiagram
participant Git
participant Helper as git-remote-gitlawb
participant Node
Git->>Helper: Command list + flush
Git->>Helper: Push certificate + push-cert-end
Git->>Helper: Push options + flush
opt Objects are updated
Git->>Helper: PACK data
end
Helper->>Node: Complete receive-pack POST
Node-->>Helper: Report status
Helper-->>Git: Report status
Reviews (2): Last reviewed commit: "fix(git-remote): consume negotiated push..." | Re-trigger Greptile
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| if pkt_len == 0 { | ||
| body.extend_from_slice(&len_bytes); | ||
| if saw_command { | ||
| break; | ||
| } |
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If a repository is configured for signed pushes, Git sends commands inside a push certificate ending with a push-cert-end pkt-line, not a separate flush-terminated command list. This loop does not stop at that boundary. For a pack-bearing push, it reads the following PACK header as a pkt-line length and fails; for a delete-only push, it can wait indefinitely. The new push-certificate test uses a certificate flush followed by a separate command list, so it does not cover Git's actual framing.
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Inline comments:
In `@crates/git-remote-gitlawb/src/main.rs`:
- Around line 589-610: Update read_receive_pack_request to recognize push-cert
as the command section: parse the certificate framing beginning with
push-cert\0capabilities, consume signed commands through push-cert-end, and
derive pack_expected from those embedded commands instead of treating subsequent
certificate or PACK data as ordinary pkt-lines. Correctly handle duplicated
push-option lists and add fixtures covering signed requests both with and
without push options, replacing the invalid command-plus-flush-plus-certificate
fixtures.
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crates/git-remote-gitlawb/src/main.rs
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| if caps.split(' ').any(|c| c.starts_with("push-options")) { | ||
| while let Some(_opt) = read_pkt(stdin, &mut body)? {} | ||
| } | ||
| if caps.split(' ').any(|c| c.starts_with("push-cert")) { | ||
| while let Some(line) = read_pkt(stdin, &mut body)? { | ||
| if line == b"push-cert-end\n" { | ||
| break; | ||
| } | ||
| } | ||
| } |
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When push-cert and push-options are both negotiated, Git sends the push certificate before the separately flush-terminated push options, but these branches read them in the opposite order. The options loop consumes both sections through the options flush, so the certificate loop then treats the following PACK header as a pkt-line and rejects a pack-bearing push, or waits indefinitely for more input on a delete-only push. Read the certificate before the options and add coverage for a signed push carrying push options.
| if caps.split(' ').any(|c| c.starts_with("push-options")) { | |
| while let Some(_opt) = read_pkt(stdin, &mut body)? {} | |
| } | |
| if caps.split(' ').any(|c| c.starts_with("push-cert")) { | |
| while let Some(line) = read_pkt(stdin, &mut body)? { | |
| if line == b"push-cert-end\n" { | |
| break; | |
| } | |
| } | |
| } | |
| if caps.split(' ').any(|c| c.starts_with("push-cert")) { | |
| while let Some(line) = read_pkt(stdin, &mut body)? { | |
| if line == b"push-cert-end\n" { | |
| break; | |
| } | |
| } | |
| } | |
| if caps.split(' ').any(|c| c.starts_with("push-options")) { | |
| while let Some(_opt) = read_pkt(stdin, &mut body)? {} | |
| } |
…nd no command list
2 participants
Summary
git push --deleteagainst agitlawb://remote deadlocked because the helper read stdin to EOF for the receive-pack request, while git holds the pipe open for the report-status response after a delete-only command list. The request is now delimited by the protocol's own boundary: the flush after the command list.Motivation & context
Closes #369
Kind of change
What changed
read_receive_pack_requestreads the command list's pkt-lines to its terminating flush, then reads the pack to EOF only when a command has a non-zero new-oid. A delete-only push (all-zero new-oids) posts immediately instead of waiting for an EOF that never comes. Push-cert blocks read past their own flush since only a command-bearing block ends the request. Malformed pkt-line lengths bail, same strictness asread_upload_pack_round.git receive-pack --stateless-rpc).How a reviewer can verify
cargo test -p git-remote-gitlawbThe regression proof is
real_git_push_delete_completes: a realgit push --deletethrough the built helper against the shim completes in one POST and deletes the ref server-side. On the oldread_to_endshape it hangs for the full 30s deadline (verified by reverting the function body).Before you request review
cargo test --workspacepasses locallycargo fmt --allandcargo clippy --workspace --all-targets -- -D warningsare cleanfeat(...),fix(...),docs(...)).env.exampleupdated if behavior or config changed (or N/A)Protocol & signing impact
did:key, Ed25519 / RFC 9421 signatures, UCAN, ref certs, or P2P wire formatsNotes: this changes how the helper FRAMES the receive-pack request it reads from git, not the wire bytes it sends: the POST body is byte-identical (commands, flush, pack when present). The request boundary moved from EOF to the command flush, which is what the protocol specifies.
Notes for reviewers
BlockAfterSeed(the live-pipe reader from the earlier multi-round-fetch work) reproduces the hang in a unit test; a Cursor would EOF and hide it. EOF is still honored so git versions that close the pipe early keep working.Summary by CodeRabbit
Bug Fixes
Tests