fix: use atomic rename to eliminate TOCTOU race in show-cache#61
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claude[bot] merged 1 commit intomainfrom Feb 27, 2026
Merged
fix: use atomic rename to eliminate TOCTOU race in show-cache#61claude[bot] merged 1 commit intomainfrom
claude[bot] merged 1 commit intomainfrom
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Replace read-then-delete with rename-then-read so that concurrent UserPromptSubmit hook invocations cannot both read the display cache before either has deleted it. os.Rename is atomic on POSIX systems, so only the first caller wins the rename; subsequent callers get IsNotExist and exit cleanly without re-emitting the context bomb. Fixes #58 Co-Authored-By: Grey Newell <greyshipscode@gmail.com> Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> Co-authored-by: claude[bot] <claude[bot]@users.noreply.github.com>
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Summary
Replace the read-then-delete pattern in
cmd/showcache.gowith an atomic rename-then-read to fix a TOCTOU race where two concurrentshow-cacheinvocations could both read the display cache before either deleted it, causing the context bomb to be injected twice.Changes
cmd/showcache.go: Atomically renamecachePath→cachePath + ".consuming"before reading. Only the process that wins the rename reads and emits the data; subsequent callers getIsNotExistfrom the rename and exit silently.os.Renameis atomic on all POSIX systems, so this is a correct single-operation guard against concurrent access.Fixes #58
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