fix: propagate writes across hard links sharing the same inode#385
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fix: propagate writes across hard links sharing the same inode#385toddr-bot wants to merge 1 commit intocpan-authors:mainfrom
toddr-bot wants to merge 1 commit intocpan-authors:mainfrom
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link() copied contents as an independent scalar, so writing to one hard link was invisible through the other — violating POSIX semantics where hard links share the same underlying data. Add _sync_hardlink_contents() that propagates contents changes to all mocks sharing the same inode. Called from FileHandle _write_bytes(), the contents() setter, and __open truncation path. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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What
Hard link writes now propagate to all mocks sharing the same inode.
Why
link()copied contents as an independent scalar, so writing through onehard link was invisible when reading through the other — violating POSIX
semantics where hard links share the same underlying data block.
How
Added
_sync_hardlink_contents()that iterates same-inode mocks (samepattern as the existing nlink propagation in
unlink()) and syncs thecontents scalar. Called from three write paths:
FileHandle::_write_bytes()— after print/syswritecontents()setter — coverstruncate()and programmatic updates__opentruncation — the>/+>mode path that bypasses the setterThe sync is guarded by
nlink > 1so non-linked files pay zero cost.Testing
7 new test cases in
t/symlink_link.t:open('>')propagationtruncate()propagationFull suite: 1594 tests pass (pre-existing
fh-ref-leak.tfailure excluded).