* perf(process): reuse a verified Darwin ownership helper across processes
Every REA process on macOS compiled the Swift ownership helper into a fresh
temporary root and then paid macOS's first-launch assessment of that new
executable: 408 ms + 325 ms of a 1.4 s `rea inspect-macho /bin/ls`.
With the default xcrun compiler and module cache, the reader now keeps one
content-addressed copy under ~/Library/Caches/rea/process-helper/<key>/.
The key covers the helper sources, toolchain selection, architecture and
Darwin release. A copy is executed only after the cache root, entry and
files are verified as current-user owned, not group- or world-writable,
not links, and digest-matched to the entry manifest. Malformed entries
owned by the user are removed and rebuilt; linked or foreign entries are
left untouched and the per-process compile runs as before. Any cache
failure falls back to that compile, so the cache never fails an ownership
operation.
A miss compiles exactly as before, then publishes a copy through an atomic
rename, keeping the first concurrent publisher, and runs the shared copy.
That way its first-launch assessment is paid once. Per-run roots keep their
existing cleanup; published entries are never removed by close or exit.
An explicit REA_DARWIN_SWIFTC_PATH or REA_DARWIN_MODULE_CACHE_PATH keeps the
per-process compile and writes nothing to the cache. `rea uninstall
--purge-data` removes the namespace.
Fixes#2483
Co-Authored-By: Claude Opus 5.5 <[email protected]>
* fix(process): harden the shared Darwin helper cache
Address review findings on the shared ownership-helper cache:
- Verify every real parent of the cache root: each must belong to the user
or root and not be writable by others (sticky root-owned directories
excepted), so no other user can rename a verified entry. Execute through
the real path.
- Open manifest and helper through the owned non-blocking regular-file
reader, so a FIFO cannot block preparation, and retain handles whose close
fails.
- Key entries on the swiftc and SDK that xcrun itself resolves, including
their real paths, sizes and modification times. DEVELOPER_DIR, TOOLCHAINS,
xcode-select and in-place updates therefore select new entries.
- Never remove or replace an invalid or published entry. Removal could race
another process that has verified or is running that path, so such an
entry falls back to the per-process compile.
- Give the cache a close() that retries retained staging removals and
handle closes and reports ProviderCleanupError while any remain. The
reader closes it with its per-run root.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
* fix(process): keep cache lookups owned and fall back from unlaunchable helpers
Address the second round of review on the shared ownership-helper cache:
- Pass the preparation signal to both xcrun toolchain lookups, and wait for
every started lookup before reporting the first failure. Cancellation and
close then stop a stalled lookup instead of waiting out its deadline.
A failed or cancelled key computation is retried by the next lookup.
- When the verified shared copy cannot launch (EACCES, EPERM, ENOEXEC,
ENOENT or an unrequested SIGKILL, for example from a noexec home volume),
the reader stops using the cache. It reuses its own compiled helper or
compiles one, and retries the read once.
- Anchor the cache's returned cleanup errors as cleanupRoot does, so every
error returned while cleanup was pending resolves after a retry succeeds.
- Build the cache path with appendCallerPath, so a home with symlinks and
`..` keeps the caller's meaning instead of being normalized lexically.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
* fix(process): keep concurrent fallbacks and dual cleanup failures
Each helper read now records before awaiting whether it launched the shared
copy, so a concurrent read's fallback cannot hide its own. When the per-run
root and the cache's retained resources both fail one close, the returned
error composes both. It stays incomplete until both owners recover.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
* fix(process): refuse shared helpers that an ACL lets others write
macOS ACLs can grant writes that the POSIX mode bits do not show. On
Darwin, lookup and publication list the real ancestors, the entry and its
files with `ls -lde`, and refuse sharing when any ACL entry allows a
write-class right. The default `group:everyone deny delete` entries on
macOS home folders are unaffected. The unlaunchable-helper test now removes
the execute bit from a verified copy, which refuses launch on both Linux
and macOS.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
---------
Co-authored-by: Claude Opus 5.5 <[email protected]>
