mathiasandClaude Opus 5.5
b6f7dac46e
Option 1 of #157, slice 2. readExcerpt (brain_context), api.ReadNote (brain_get / read-after-write) and notes.ReadScoped (brain_read) read the Syncthing-shared brain by path. Under a symlink swap race each leaked an outside file hundreds of thousands of times in 1.5s, including brain_read, whose Lstat check was raced by the reopen-by-name; a FIFO blocked os.ReadFile. - All three read through brainfs (os.Root, regular files only, non-blocking open, type check on the handle). - brainfs.ReadRegularMax checks a size limit on the opened handle; notes keeps its ErrTooLarge. - New internal/brainfs/brainfstest: the shared swap-race harness (symlink and held-writer FIFO swappers, awaited before TempDir cleanup; AssertNoLeak / AssertNoHang) for this and later slices. Tests red first: each reader under a symlink-swap race and a held-writer FIFO race, plus static checks. Flipped: readExcerpt back to os.ReadFile is red. Refs #157 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>