Review of the #233 implementation found two correctness defects. Both
are cases where the FIRST fix for #233 was itself wrong, which is worth
naming: this lane repaired absolute globs and, in the same change, broke
a case that had worked since May.
P1 --- `resolve_watcher` returned "absolute" for EVERY string, so the
form was carried but derived from the union arm rather than from the
pattern. A bare `*.txt` is a valid relative pattern (LSP 3.17 defines
`Pattern` relative to a base path; VS Code treats string watchers as
applying across workspace folders), and classifying it absolute matched
it against `<base>/foo.txt`, which `^[^/]*%.txt$` can never match. A
leading `/` is what makes a pattern absolute. The `filewatchflat` test
could not catch this: it sends the RelativePattern OBJECT form, so it
constrains the object arm, never the string arm the regression lived in
--- the framing's own F1 finding, repeating inside the lane that named
it.
P2 --- `scan_tree` awaits `read_dir` once per directory, so the watcher
coroutine sits suspended for most of a tick with `_sleep` already
cleared. A cancel arriving there sets `cancelled` and has no sleep to
interrupt, and the resumed scan ran on to `did_change_watched_files`:
one stale batch under the superseded pattern, which is a wrong-pattern
notification the server acts on. Cancellation and liveness are rechecked
after the scan.
Both tests are mutation-checked and each bite fails only its own defect.
Reverting P1 fails the bare-string test alone --- the absolute test
still passes, so the two readings are independent. Deleting P2's recheck
reproduces the defect verbatim: `.received = "1 file:///…/foo.txt"`,
a batch from a watcher that was already cancelled.
P2's witness needs a seam. The race is a cancel landing during one of
the scan's suspensions, which no arrangement of real timing produces on
demand --- the same situation, and the same device, as `git.lua`'s
`_deliver_status`. `pmacs.lsp._after_scan_for_tests` is nil in
production and is handed the SCAN RESULT deliberately: a test that
cancels on any other scan passes with the recheck deleted, because the
loop would break at the post-sleep check and emit nothing anyway.
Gates: 9/9 green.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016bqGA6s9tTUFzYpbeW3tai
Levi Neuwirth
2a16e0eed5