Go go.work audit: false NotAMember for a use path through a missing dir on macOS (breaks macOS test job) #1409

[agent] Found while checking the full-scope CI run for #1407. It breaks the macOS test job, so tonight's nightly on main is expected to go red.

What fails

vendor::go_consumer_sync::tests::go_work_that_does_not_use_the_project_makes_the_replace_inert (added in #1393, merged 2026-10-11 19:48 UTC, after the last nightly) fails on macos-latest: run 38191238691, job 114624594929.

panicked at crates/socket-patch-core/src/vendor/go_consumer_sync.rs:923:13:
assertion `left == right` failed: ./x/../app
  left: [Workspace { module: "example.com/upstream", version: "v1.0.0", conflict: NotAMember { work_file: "/private/var/folders/.../go.work" } }]
 right: []

The spellings ./app, app, ./app/ and "./app" all pass. Only ./x/../app fails.

Root cause

same_dir_key (go_consumer_sync.rs:468) calls std::fs::canonicalize on the raw joined path <ws>/x/../app. canonicalize needs every component to exist, and x doesn't, so the call errors and the code falls back to the lexical path /var/.../app. The project root does exist and canonicalizes to /private/var/.../app, because /var is a symlink on macOS. The two keys differ, so the use entry doesn't match the project and the audit reports NotAMember.

It isn't only a test problem. Any user whose go.work use path passes through a directory that doesn't exist, and whose project sits under a symlinked path (macOS /var or /tmp, a symlinked home or checkout), gets a false "go.work does not use this project" conflict. Go itself resolves use paths lexically (filepath.Clean), so ./x/../app is a valid member for go.

Repro on Linux

Point TMPDIR at a symlinked directory:

mkdir -p /tmp/real && ln -sfn /tmp/real /tmp/link
TMPDIR=/tmp/link cargo test -p socket-patch-core --lib go_consumer_sync
# 8 passed; 1 failed (same assertion)

Proposed fix (verified locally)

Normalize lexically first, then canonicalize. This matches go's filepath.Clean and still resolves symlinks when the cleaned path exists:

 fn same_dir_key(dir: &Path) -> PathBuf {
     let abs = std::env::current_dir().unwrap_or_default().join(dir);
-    std::fs::canonicalize(&abs)
-        .unwrap_or_else(|_| crate::utils::relpath::normalize_lexically_keeping_escapes(&abs))
+    let lexical = crate::utils::relpath::normalize_lexically_keeping_escapes(&abs);
+    std::fs::canonicalize(&lexical).unwrap_or(lexical)
 }

With this patch, TMPDIR=/tmp/link cargo test -p socket-patch-core --lib go_consumer_sync gives 9 passed. The rest of vendor:: matches main: the only two failures, pypi_poetry::...wire_write_failure... and pypi_requirements::...wire_failure_rolls_back..., fail on unpatched main too when run as root in the agent sandbox.

This is product code in the Go lane (first issue-fixer instance), so I haven't claimed it. The doc comment above same_dir_key should be updated with the fix.

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