gh-149578: Fix tarfile.open failing on PAX archives with only global headers - #149647
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ethanfurman merged 2 commits intoSep 1, 2026
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…lobal headers When a PAX format tar archive contains only global headers and no regular members, tarfile.open() raised ReadError because the EOFHeaderError from reaching end-of-archive after the global header was being caught and converted to SubsequentHeaderError in TarInfo._proc_pax(). This prevented the caller from handling end-of-archive normally. Fix by letting EOFHeaderError propagate when processing a global header (XGLTYPE), while still treating it as a SubsequentHeaderError for extended headers (XHDTYPE) where a following file entry is mandatory.
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All commit authors signed the Contributor License Agreement. |
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Wow, that was fast, thank you, Shadi! |
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Very Welcome @spbnick |
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Please, if you use an LLM, first read our policy against them and mention their usage. The summary is entirely AI-generated and contains unnecessary information that does not help reviewers. |
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This PR is stale because it has been open for 90 days with no activity. |
ethanfurman
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Aug 31, 2026
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needs backport to 3.15
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Thanks @ShadiBahaa for the PR, and @ethanfurman for merging it 🌮🎉.. I'm working now to backport this PR to: 3.15. |
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GH-156792 is a backport of this pull request to the 3.15 branch. |
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Summary
Fix
tarfile.open()raisingReadErrorwhen opening a PAX format tar archive that contains only global headers and no regular file members.Root cause: In
TarInfo._proc_pax(), after processing a global header (XGLTYPE), the code tries to read the next header. If the archive has no file entries after the global header, this read encounters the end-of-archive marker and raisesEOFHeaderError. This exception was being caught by the genericexcept HeaderErrorclause and converted toSubsequentHeaderError, which bothTarFile.next()and the append-mode initialization loop treat as a fatal error.Fix: Catch
EOFHeaderErrorseparately before the genericHeaderErrorhandler. For global headers (XGLTYPE), let theEOFHeaderErrorpropagate so callers handle end-of-archive normally. For extended headers (XHDTYPE), a following file entry is mandatory, so the error is still converted toSubsequentHeaderError.Test plan
test_pax_global_header_empty_archiveinPaxWriteTestthat: