feat(tty): serialize terminal output writes with a lock#31
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Add an internal `lock` package wrapping a binary semaphore (Semaphore(1)) and route Tty::write / Tty::write_string through it, so a single write lands on the terminal atomically even when multiple tasks write concurrently. with_lock pairs acquire/release via defer, releasing on both the normal and failure paths. Upgrade moonbitlang/async 0.19.1 -> 0.19.4 for the semaphore API. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The win32 console white-box test builds a Tty record literal directly, which must include the new write_lock field. Fixes the windows-latest CI check. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The Semaphore API the write lock needs already exists in 0.19.1 with an identical signature, so the bump to 0.19.4 was unnecessary. 0.19.4 also changed Windows-affecting internals and regressed the Tty write path on windows-latest (Tty::open test timed out). Staying on 0.19.1 keeps the lock feature while matching the version the tests module already pins. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Add docs/plans/2026-06-15-output-write-lock.md with goal, target files, public API changes, invariants, acceptance criteria, validation, and the public API audit notes required when .mbti files change, and add the TTY-23 row to the execution board. Addresses the plan-discipline review. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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What
Output writes on
Ttyare now serialized through an internal lock, so a singleTty::write/Tty::write_stringcall lands on the terminal atomically even when multiple tasks write concurrently. Previously a large write could span multiplewrite_oncesyscalls with suspension points in between, letting another writer interleave its bytes and garble escape sequences / frames.Changes
moonbit-community/tty/internal/lockwrapping a binary semaphore (Semaphore(1)):Lock::new/acquire/try_acquire/releasewith_lock(action)pairs acquire/release viadefer, releasing on both the normal and failure paths (deferis registered only afteracquiresucceeds, so a cancelled acquire never releases a lock it doesn't hold).Ttygains awrite_lock : @lock.Lockfield (both Windows and non-Windows variants);write/write_stringroute throughwrite_lock.with_lock(...).moonbitlang/async0.19.1→0.19.4for the semaphore API.Scope / notes
write/write_string(all ofstyle.mbt/decstbm.mbtcommand methods and thequery_*helpers route here), so all output-stream writes are covered.size.mbt/state.mbtonly touchself.output.fd()for ioctls (tcgetattr/tcsetattr/window size), which are independent atomic syscalls and intentionally not locked.writes (e.g.enable_mouse) is a sequence of atomic writes, not one atomic unit — another writer can still interleave between them. Frame-level atomicity requires assembling one buffer perwrite.Validation
moon check/moon test(165 passed) /moon fmt/moon infoall clean.🤖 Generated with Claude Code