[internal/wclayer]: fix import temp dir leak on layer extract failure#2778
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anmaxvl merged 1 commit intoJun 18, 2026
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When layer extraction fails because the disk is full, legacyLayerWriter.reset
returned early from bufWriter.Flush (ENOSPC) before closing currentFile and
backupWriter. On Windows the still-open handle prevented os.RemoveAll from
deleting the temporary import directory created by os.MkdirTemp("", "hcs"),
which by default (if not explicitly set) resolves to C:\Windows\SystemTemp\hcs*.
As a result every failed PullImage layer extract leaked an hcs* directory and
compounded disk-space exhaustion that never self-healed.
Move the handle-close logic into a deferred func in reset so the file and
backup handles are always released, even on the flush-error path, allowing the
deferred RemoveAll in legacyLayerWriterWrapper.Close to succeed. Also clean up
importPath in NewLayerWriter when newLegacyLayerWriter fails, matching
NewLayerReader's exportPath handling.
Adds wclayer reset unit tests covering the flush-error and success paths.
Co-authored-by: Claude Opus 4.8
Signed-off-by: Maksim An <maksiman@microsoft.com>
msscotb
approved these changes
Jun 17, 2026
helsaawy
approved these changes
Jun 18, 2026
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When layer extraction fails because the disk is full, legacyLayerWriter.reset returned early from bufWriter.Flush (ENOSPC) before closing currentFile and backupWriter. On Windows the still-open handle prevented os.RemoveAll from deleting the temporary import directory created by os.MkdirTemp("", "hcs"), which by default (if not explicitly set) resolves to C:\Windows\SystemTemp\hcs*. As a result every failed PullImage layer extract leaked an hcs* directory and compounded disk-space exhaustion that never self-healed.
Move the handle-close logic into a deferred func in reset so the file and backup handles are always released, even on the flush-error path, allowing the deferred RemoveAll in legacyLayerWriterWrapper.Close to succeed. Also clean up importPath in NewLayerWriter when newLegacyLayerWriter fails, matching NewLayerReader's exportPath handling.
Adds wclayer reset unit tests covering the flush-error and success paths.
Co-authored-by: Claude Opus 4.8