entry: fix fscache stale directory listing in parallel checkout pathspec#917
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entry: fix fscache stale directory listing in parallel checkout pathspec#917tyrielv wants to merge 1 commit into
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When checkout.workers > 1 and core.fscache is enabled on Windows, 'git checkout <tree> -- <pathspec>' fails when restoring files into directories that do not yet exist on disk. Two failure modes occur: 1. create_directories(): the fscache returns a stale directory listing that does not include a just-created directory. has_dirs_only_path() reports it as non-existent, triggering the unlink+mkdir recovery path which fails with 'cannot create directory: Directory not empty'. 2. write_pc_item(): after writing and closing a file, lstat() cannot see it through the stale fscache, failing with 'unable to stat just-written file'. With workers=1, write_entry() calls flush_fscache() after each file, keeping the cache in sync. With workers>1, enqueue_checkout() defers the write (and the flush), leaving the cache stale for subsequent entries. Fix both by adding flush_fscache() calls after mkdir() in create_directories() and before lstat() in write_pc_item(). On non-Windows platforms flush_fscache() is a no-op. Assisted-by: Claude Opus 4.6 Signed-off-by: Tyrie Vella <tyrielv@gmail.com>
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Upstream PR: git-for-windows#6250
Problem
git checkout <tree> -- <pathspec>withcheckout.workers > 1andcore.fscache=true(Windows) fails when restoring files into directories that do not yet exist on disk. Two failure modes:fatal: cannot create directory at '...': Directory not empty(exit 128)error: unable to stat just-written file '...'(exit 255)100% reproducible when two or more files share a not-yet-created parent directory.
Root Cause
The Windows fscache caches directory listings that become stale when
create_directories()creates new parent directories viamkdir()or whenwrite_pc_item()writes new files. Withworkers=1,write_entry()callsflush_fscache()after each file, keeping the cache in sync. Withworkers>1,enqueue_checkout()defers the write (and the flush), leaving the cache stale for subsequent entries.Fix
Add
flush_fscache()calls:create_directories()after each successfulmkdir(), sohas_dirs_only_path()sees the new directorywrite_pc_item()beforelstat()of the just-written fileOn non-Windows platforms
flush_fscache()is a no-op.Test
Adds a regression test to
t2080-parallel-checkout-basics.sh(MINGWprereq) that deterministically reproduces the bug: two files sharing a nested parent directory, deleted in a second commit, then restored viagit checkout <tree> -- <pathspec>withworkers=2.CI confirmed the test fails without the fix.
Bug: https://dev.azure.com/microsoft/OS/_workitems/edit/62260193