chore: refresh PR head

crates/git-remote-gitlawb/src/main.rs

@@ -287,8 +287,10 @@ fn handle_connect<R: Read>(
     //    this into one POST deadlocks a multi-round fetch (#117).
     //
     //  git-receive-pack (push):
-    //    Git sends ref-update commands + the complete PACK blob, then closes its
-    //    write pipe. read_to_end is safe and correct here, a single POST.
+    //    Git sends the ref-update command list (pkt-lines ending in a flush),
+    //    then the complete PACK blob only when a command has a non-zero new-oid.
+    //    A delete-only push sends no pack, and git holds its write pipe open for
+    //    the report-status response, so EOF cannot delimit the request (#369).
 
     let post_url = format!("{}/{}", repo_base, service);
 
@@ -296,10 +298,7 @@ fn handle_connect<R: Read>(
         return negotiate_upload_pack(&client, &post_url, service, signing_key, stdin, &mut stdout);
     }
 
-    let mut request_body = Vec::new();
-    stdin
-        .read_to_end(&mut request_body)
-        .context("reading receive-pack request")?;
+    let request_body = read_receive_pack_request(stdin)?;
     tracing::debug!("pack request: {} bytes from git", request_body.len());
 
     if request_body.is_empty() {
@@ -535,6 +534,108 @@ fn read_upload_pack_round<R: Read>(stdin: &mut R) -> Result<(Vec<u8>, RoundEnd)>
     }
 }
 
+/// Read one git-receive-pack request: optional `shallow` lines, then EITHER a
+/// command list (pkt-lines terminated by a flush) or a push-cert block
+/// (pkt-lines terminated by a "push-cert-end" line), then the negotiated
+/// push-options block, then the pack ONLY when a command carries a non-zero
+/// new-oid.
+///
+/// A delete-only push sends no pack, and git holds its write pipe open waiting
+/// for the report-status response, so a plain read_to_end deadlocks the two
+/// (#369). A signed push is the other trap: when the client sends a push-cert
+/// it sends NO command list at all (the commands live inside the cert), so the
+/// request starts with a "push-cert" line and no flush ever arrives. The
+/// negotiated capability list is on the push-cert line, or on the first
+/// command line after its NUL when there is no cert. EOF at any point also
+/// ends the read, covering git versions that close the pipe early.
+fn read_receive_pack_request<R: Read>(stdin: &mut R) -> Result<Vec<u8>> {
+    /// Read one pkt-line into `body` (length prefix + data), returning its data
+    /// or `None` on flush or EOF. Malformed lengths bail rather than collapse
+    /// into a synthesized flush (#192 F5).
+    fn read_pkt<R: Read>(stdin: &mut R, body: &mut Vec<u8>) -> Result<Option<Vec<u8>>> {
+        let mut len_bytes = [0u8; 4];
+        match stdin.read_exact(&mut len_bytes) {
+            Ok(()) => {}
+            Err(e) if e.kind() == io::ErrorKind::UnexpectedEof => return Ok(None),
+            Err(e) => return Err(e.into()),
+        }
+        let Ok(len_hex) = std::str::from_utf8(&len_bytes) else {
+            bail!("malformed pkt-line length prefix: non-UTF-8 bytes {len_bytes:02x?}");
+        };
+        let Ok(pkt_len) = usize::from_str_radix(len_hex, 16) else {
+            bail!("malformed pkt-line length prefix: non-hex {len_hex:?}");
+        };
+        body.extend_from_slice(&len_bytes);
+        if pkt_len == 0 {
+            return Ok(None);
+        }
+        if pkt_len < 4 {
+            bail!("invalid pkt-line length: {pkt_len}");
+        }
+        let mut data = vec![0u8; pkt_len - 4];
+        stdin
+            .read_exact(&mut data)
+            .context("reading pkt-line data")?;
+        body.extend_from_slice(&data);
+        Ok(Some(data))
+    }
+
+    /// "<40-hex old> <40-hex new> <refname>" — the command shape, whether it
+    /// appears in a command list or inside a push-cert.
+    fn is_command(data: &[u8]) -> bool {
+        data.len() >= 82
+            && data[..40].iter().all(|b| b.is_ascii_hexdigit())
+            && data[40] == b' '
+            && data[41..81].iter().all(|b| b.is_ascii_hexdigit())
+            && data[81] == b' '
+    }
+
+    let mut body = Vec::new();
+    let mut caps = String::new();
+    let mut pack_expected = false;
+    let mut in_cert = false;
+    loop {
+        let Some(data) = read_pkt(stdin, &mut body)? else {
+            // Flush ends a command list; EOF ends anything. A cert has no
+            // legal flush inside it, so the same break covers malformed
+            // input without hanging.
+            break;
+        };
+        if !in_cert && data.starts_with(b"push-cert") {
+            in_cert = true;
+            if let Some(nul) = data.iter().position(|&b| b == 0) {
+                caps = String::from_utf8_lossy(&data[nul + 1..]).into_owned();
+            }
+            continue;
+        }
+        if in_cert && data == b"push-cert-end\n" {
+            break;
+        }
+        if is_command(&data) {
+            if caps.is_empty() {
+                if let Some(nul) = data.iter().position(|&b| b == 0) {
+                    caps = String::from_utf8_lossy(&data[nul + 1..]).into_owned();
+                }
+            }
+            if data[41..81].iter().any(|&b| b != b'0') {
+                pack_expected = true;
+            }
+        }
+    }
+    // When both are negotiated the push-options block follows the cert; when
+    // only options are negotiated it follows the command flush. Either way it
+    // is pkt-lines to a flush.
+    if caps.split(' ').any(|c| c.starts_with("push-options")) {
+        while read_pkt(stdin, &mut body)?.is_some() {}
+    }
+    if pack_expected {
+        stdin
+            .read_to_end(&mut body)
+            .context("reading receive-pack pack")?;
+    }
+    Ok(body)
+}
+
 /// POST one self-contained stateless-RPC request body and stream the response to
 /// `stdout`. Signs the request when `signing_key` is present, so every round of a
 /// private-repo fetch carries the caller's signature (the node visibility-gates
@@ -2017,6 +2118,184 @@ mod tests {
         assert!(help.ends_with('\n'));
     }
 
+    // ── #369 delete-only push deadlock ───────────────────────────────────────
+
+    /// A delete-only receive-pack request ends at the command flush; git then
+    /// holds the write pipe open for the report and sends no pack. A reader that
+    /// blocks after the command list reproduces the hang that a Cursor (EOF)
+    /// hides. The read must return at the flush, inside the timeout.
+    #[test]
+    fn delete_only_receive_pack_request_returns_at_command_flush() {
+        let old = "a".repeat(40);
+        let zero = "0".repeat(40);
+        let mut seed = Vec::new();
+        seed.extend_from_slice(&pkt(&format!("{old} {zero} refs/heads/gone\n")));
+        seed.extend_from_slice(b"0000"); // command-list flush; git then blocks
+
+        let (tx, rx) = std::sync::mpsc::channel::<()>();
+        let mut reader = BlockAfterSeed {
+            seed: io::Cursor::new(seed),
+            gate: rx,
+        };
+
+        let (done_tx, done_rx) = std::sync::mpsc::channel::<Vec<u8>>();
+        let handle = std::thread::spawn(move || {
+            let _ = done_tx.send(read_receive_pack_request(&mut reader).unwrap());
+        });
+
+        let got = done_rx.recv_timeout(std::time::Duration::from_secs(2));
+        let _ = tx.send(()); // unblock the reader so the thread can exit
+        let _ = handle.join();
+
+        let body = got.expect(
+            "read_receive_pack_request blocked past the command flush waiting for \
+             a pack a delete-only push never sends (#369)",
+        );
+        assert!(
+            body.ends_with(b"0000"),
+            "the request body keeps the command list and its flush terminator"
+        );
+    }
+
+    /// A push carrying objects still reads the pack through to EOF, and the
+    /// command flush sits between the commands and the pack in the body.
+    #[test]
+    fn receive_pack_request_with_pack_reads_through_eof() {
+        let old = "a".repeat(40);
+        let new = "b".repeat(40);
+        let mut stream = Vec::new();
+        stream.extend_from_slice(&pkt(&format!(
+            "{old} {new} refs/heads/main\0 report-status-v2\n"
+        )));
+        stream.extend_from_slice(b"0000");
+        stream.extend_from_slice(b"PACK\x00\x00\x00\x02fakepack");
+
+        let mut stdin = io::Cursor::new(stream);
+        let body = read_receive_pack_request(&mut stdin).unwrap();
+        let pos = body.windows(4).position(|w| w == b"0000").unwrap();
+        assert_eq!(
+            &body[pos + 4..],
+            b"PACK\x00\x00\x00\x02fakepack",
+            "a non-zero new-oid means the pack follows the flush"
+        );
+    }
+
+    /// A signed delete-only push sends NO command list: the request starts
+    /// with the "push-cert" line, the commands live inside the cert, and the
+    /// cert ends with a "push-cert-end" pkt-line (not a flush). The reader
+    /// must return after push-cert-end without waiting on the pipe.
+    #[test]
+    fn signed_delete_only_push_returns_after_push_cert_end() {
+        let old = "a".repeat(40);
+        let zero = "0".repeat(40);
+        let mut seed = Vec::new();
+        seed.extend_from_slice(&pkt("push-cert\0 report-status-v2 push-cert\n"));
+        seed.extend_from_slice(&pkt("certificate version 0.1\n"));
+        seed.extend_from_slice(&pkt("pusher did:key:z6Mk\n"));
+        seed.extend_from_slice(&pkt("\n")); // empty line ends the headers
+        seed.extend_from_slice(&pkt(&format!("{old} {zero} refs/heads/gone\n")));
+        seed.extend_from_slice(&pkt("sig-line\n"));
+        seed.extend_from_slice(&pkt("push-cert-end\n"));
+        // git now blocks for the report; the pipe stays open.
+
+        let (tx, rx) = std::sync::mpsc::channel::<()>();
+        let mut reader = BlockAfterSeed {
+            seed: io::Cursor::new(seed),
+            gate: rx,
+        };
+
+        let (done_tx, done_rx) = std::sync::mpsc::channel::<Vec<u8>>();
+        let handle = std::thread::spawn(move || {
+            let _ = done_tx.send(read_receive_pack_request(&mut reader).unwrap());
+        });
+        let got = done_rx.recv_timeout(std::time::Duration::from_secs(2));
+        let _ = tx.send(());
+        let _ = handle.join();
+
+        let body = got.expect(
+            "read_receive_pack_request blocked past push-cert-end on a signed \
+             delete-only push (#369)",
+        );
+        assert!(
+            body.windows(6).any(|w| w == b"pusher"),
+            "the cert block is part of the request body"
+        );
+    }
+
+    /// A signed pack-bearing push: cert with the commands inside, then the
+    /// pack. Everything must land in the body.
+    #[test]
+    fn signed_pack_push_keeps_cert_and_pack() {
+        let old = "a".repeat(40);
+        let new = "b".repeat(40);
+        let mut stream = Vec::new();
+        stream.extend_from_slice(&pkt("push-cert\0 report-status-v2 push-cert\n"));
+        stream.extend_from_slice(&pkt("certificate version 0.1\n"));
+        stream.extend_from_slice(&pkt("\n"));
+        stream.extend_from_slice(&pkt(&format!("{old} {new} refs/heads/main\n")));
+        stream.extend_from_slice(&pkt("push-cert-end\n"));
+        stream.extend_from_slice(b"PACK\x00\x00\x00\x02fakepack");
+
+        let mut stdin = io::Cursor::new(stream);
+        let body = read_receive_pack_request(&mut stdin).unwrap();
+        assert!(
+            body.windows(5).any(|w| w == b"PACK\x00"),
+            "the pack follows the cert into the body"
+        );
+    }
+
+    /// A negotiated push-options block is pkt-lines ending in its own flush.
+    /// With no cert it follows the command flush; with a cert it follows
+    /// push-cert-end.
+    #[test]
+    fn receive_pack_request_consumes_a_push_options_block() {
+        let old = "a".repeat(40);
+        let new = "b".repeat(40);
+        let mut stream = Vec::new();
+        stream.extend_from_slice(&pkt(&format!(
+            "{old} {new} refs/heads/main\0 report-status-v2 push-options\n"
+        )));
+        stream.extend_from_slice(b"0000"); // command flush
+        stream.extend_from_slice(&pkt("ci.skip\n"));
+        stream.extend_from_slice(b"0000"); // options flush
+        stream.extend_from_slice(b"PACK\x00\x00\x00\x02fakepack");
+
+        let mut stdin = io::Cursor::new(stream);
+        let body = read_receive_pack_request(&mut stdin).unwrap();
+        assert!(body.windows(7).any(|w| w == b"ci.skip"), "options survived");
+        assert!(
+            body.ends_with(b"PACK\x00\x00\x00\x02fakepack"),
+            "the pack lands after the options block"
+        );
+    }
+
+    /// Cert and options together: the cert comes first and the options block
+    /// sits between push-cert-end and the pack.
+    #[test]
+    fn signed_push_with_options_reads_cert_then_options_then_pack() {
+        let old = "a".repeat(40);
+        let new = "b".repeat(40);
+        let mut stream = Vec::new();
+        stream.extend_from_slice(&pkt(
+            "push-cert\0 report-status-v2 push-cert push-options\n",
+        ));
+        stream.extend_from_slice(&pkt("certificate version 0.1\n"));
+        stream.extend_from_slice(&pkt("\n"));
+        stream.extend_from_slice(&pkt(&format!("{old} {new} refs/heads/main\n")));
+        stream.extend_from_slice(&pkt("push-cert-end\n"));
+        stream.extend_from_slice(&pkt("ci.skip\n"));
+        stream.extend_from_slice(b"0000"); // options flush
+        stream.extend_from_slice(b"PACK\x00\x00\x00\x02fakepack");
+
+        let mut stdin = io::Cursor::new(stream);
+        let body = read_receive_pack_request(&mut stdin).unwrap();
+        assert!(body.windows(7).any(|w| w == b"ci.skip"), "options survived");
+        assert!(
+            body.ends_with(b"PACK\x00\x00\x00\x02fakepack"),
+            "the pack lands after the options block"
+        );
+    }
+
     // ── #117 multi-round fetch negotiation ───────────────────────────────────
 
     /// Encode a git pkt-line: 4-byte hex length (incl. the 4 bytes) + data.

crates/git-remote-gitlawb/tests/real_git_fetch.rs

@@ -95,6 +95,36 @@ fn upload_pack(repo: &Path, advertise: bool, input: &[u8]) -> Vec<u8> {
     out.stdout
 }
 
+/// Run `git receive-pack --stateless-rpc [--advertise-refs] <repo>`, optionally
+/// feeding `input` on stdin. Returns raw stdout (the wire bytes). The receive
+/// half of `upload_pack`, used so the shim can serve a real push.
+fn receive_pack(repo: &Path, advertise: bool, input: &[u8]) -> Vec<u8> {
+    let mut cmd = Command::new("git");
+    cmd.arg("receive-pack").arg("--stateless-rpc");
+    if advertise {
+        cmd.arg("--advertise-refs");
+    }
+    cmd.arg(repo)
+        .stdin(Stdio::piped())
+        .stdout(Stdio::piped())
+        .stderr(Stdio::piped());
+    let mut child = cmd.spawn().expect("spawn git receive-pack");
+    let mut stdin = child.stdin.take().unwrap();
+    let input = input.to_vec();
+    let writer = std::thread::spawn(move || {
+        let _ = stdin.write_all(&input);
+        // drop closes stdin
+    });
+    let out = child.wait_with_output().expect("wait receive-pack");
+    writer.join().ok();
+    assert!(
+        out.status.success(),
+        "git receive-pack failed: {}",
+        String::from_utf8_lossy(&out.stderr)
+    );
+    out.stdout
+}
+
 #[derive(Clone, Copy)]
 enum ShimMode {
     /// Faithful v0 serving: pipe each POST to `git upload-pack --stateless-rpc`.
@@ -218,7 +248,21 @@ fn handle_conn(stream: TcpStream, repo: &Path, mode: ShimMode, posts: &AtomicUsi
         reader.read_exact(&mut body).ok();
     }
 
-    let (content_type, payload) = if method == "GET" && target.contains("/info/refs") {
+    let (content_type, payload) = if method == "GET" && target.contains("service=git-receive-pack")
+    {
+        // Receive-pack advertisement, same wrapper shape as upload-pack.
+        let adv = receive_pack(repo, true, b"");
+        let mut wrapped = pkt(b"# service=git-receive-pack\n");
+        wrapped.extend_from_slice(b"0000");
+        wrapped.extend_from_slice(&adv);
+        ("application/x-git-receive-pack-advertisement", wrapped)
+    } else if method == "POST" && target.ends_with("/git-receive-pack") {
+        posts.fetch_add(1, Ordering::SeqCst);
+        (
+            "application/x-git-receive-pack-result",
+            receive_pack(repo, false, &body),
+        )
+    } else if method == "GET" && target.contains("/info/refs") {
         // v0 advertisement, wrapped exactly as the node's info_refs does.
         let adv = upload_pack(repo, true, b"");
         let mut wrapped = pkt(b"# service=git-upload-pack\n");
@@ -293,6 +337,34 @@ fn fetch_with_helper(clone: &Path, node_url: &str) -> (bool, std::process::Outpu
     run_bounded(cmd, Duration::from_secs(30))
 }
 
+/// Run `git push` in `local` through the helper, same wiring and hard timeout as
+/// [`fetch_with_helper`]. `args` carries the push spec, e.g.
+/// `["--delete", "doomed"]`.
+fn push_with_helper(local: &Path, node_url: &str, args: &[&str]) -> (bool, std::process::Output) {
+    let helper_bin = PathBuf::from(env!("CARGO_BIN_EXE_git-remote-gitlawb"));
+    let helper_dir = helper_bin.parent().unwrap().to_path_buf();
+    let path_env = match std::env::var_os("PATH") {
+        Some(p) => {
+            let mut dirs = vec![helper_dir.clone()];
+            dirs.extend(std::env::split_paths(&p));
+            std::env::join_paths(dirs).unwrap()
+        }
+        None => helper_dir.clone().into_os_string(),
+    };
+
+    let mut cmd = Command::new("git");
+    cmd.arg("-C")
+        .arg(local)
+        .arg("push")
+        .arg("origin")
+        .args(args)
+        .env("PATH", path_env)
+        .env("LC_ALL", "C")
+        .env("GITLAWB_NODE", node_url)
+        .env("GITLAWB_KEY", "/nonexistent-key-for-anon-push");
+    run_bounded(cmd, Duration::from_secs(30))
+}
+
 /// A synthetic non-success `ExitStatus` used only on the unix timeout path, where
 /// `reap_group` has already consumed the child and the later `wait` returns ECHILD.
 /// The timeout branch already reports `completed == false`, so the exact status is
@@ -1242,3 +1314,77 @@ fn run_bounded_bounds_join_when_leader_exits_leaving_a_pipe_holder() {
          held pipes do not stall the joins)"
     );
 }
+
+/// #369 end-to-end: a real `git push --delete` through the helper completes.
+/// The receive-pack request for a delete-only push is commands + flush with NO
+/// pack, and git holds its write pipe open for the report — so a helper that
+/// reads stdin to EOF deadlocks against it. The shim pipes the POST to a real
+/// `git receive-pack --stateless-rpc`, so the branch actually has to be deleted
+/// server-side for the assertions to pass.
+#[test]
+fn real_git_push_delete_completes() {
+    let dir = tempfile::tempdir().unwrap();
+    let server = dir.path().join("server.git");
+    let local = dir.path().join("local");
+
+    // A bare repo holding the doomed branch, plus a live one.
+    git(
+        dir.path(),
+        &[
+            "init",
+            "--bare",
+            server.to_str().unwrap(),
+            "--initial-branch=main",
+        ],
+    );
+    let work = dir.path().join("work");
+    git(
+        dir.path(),
+        &["init", work.to_str().unwrap(), "--initial-branch=main"],
+    );
+    git(&work, &["config", "user.email", "t@t"]);
+    git(&work, &["config", "user.name", "t"]);
+    std::fs::write(work.join("f"), "x").unwrap();
+    git(&work, &["add", "f"]);
+    git(&work, &["commit", "-m", "c"]);
+    git(&work, &["branch", "doomed"]);
+    git(&work, &["push", server.to_str().unwrap(), "main", "doomed"]);
+
+    // The pusher: a local repo whose origin is the gitlawb remote pointing at
+    // the shim. Nothing needs to be fetched first; git takes the old-oid from
+    // the receive-pack advertisement.
+    git(
+        dir.path(),
+        &["init", local.to_str().unwrap(), "--initial-branch=main"],
+    );
+    git(
+        &local,
+        &["remote", "add", "origin", "gitlawb://did:key:z6MkTest/repo"],
+    );
+
+    let shim = start_shim(server.clone(), ShimMode::Normal);
+    let (completed, out) = push_with_helper(&local, &shim.base_url, &["--delete", "doomed"]);
+    let posts = shim.posts.load(Ordering::SeqCst);
+
+    assert!(
+        completed,
+        "git push --delete did not complete within the timeout (deadlock signature). stderr:\n{}",
+        String::from_utf8_lossy(&out.stderr)
+    );
+    assert!(
+        out.status.success(),
+        "git push --delete failed. stderr:\n{}",
+        String::from_utf8_lossy(&out.stderr)
+    );
+    assert_eq!(posts, 1, "a delete-only push is exactly one POST");
+    let gone = Command::new("git")
+        .arg("-C")
+        .arg(&server)
+        .args(["rev-parse", "--verify", "--quiet", "refs/heads/doomed"])
+        .output()
+        .unwrap();
+    assert!(
+        !gone.status.success(),
+        "refs/heads/doomed must be deleted in the server repo"
+    );
+}