Replace astral-tokio-tar with tar-codec

[woodruffw]

Summary

WIP, I've done the read path but not the (full) write path yet.

This adds a preview feature that replaces astral-tokio-tar with tar-codec on both our read and write paths.

Notes:

• Merge Reject uv build if the cache dir is enclosed #19991 first to seal of the kind of failure that build::build_with_hardlink is currently testing indirectly
• Rework this into a preview feature

Test Plan

Ensure existing tests don't break, plus new tests.

[codspeed-hq]

Merging this PR will improve performance by ×2.1

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 2 improved benchmarks
✅ 21 untouched benchmarks
⏩ 6 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	WallTime	unpack_sdist_many_files	731 ms	326.7 ms	×2.2
⚡	Simulation	unpack_sdist_many_files	333.4 ms	176.6 ms	+88.8%

Tip

Curious why this is faster? Use the CodSpeed MCP and ask your agent.

---

_{Comparing ww/tar-codec (2dcf539) with main (3a9573c)}

Footnotes

1. 6 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[zanieb]

Is the intent to do this behind preview first, or?

[woodruffw]

Is the intent to do this behind preview first, or?

I didn't have a strong intent either way 🙂. I guess we probably should?

[charliermarsh]

I would personally be ok to do this outside of preview, as long as we have sufficient testing, since it's not clear that we want to change any specific behavior in response to user feedback, etc.

[zanieb]

I think the main issue is that it will be much more restrictive. I guarantee we will break people.

[charliermarsh]

That makes sense, I forgot that this would actually be stricter. I’m a little worried that we won’t get enough feedback to know when we can stabilize it.

[zanieb]

I think another benefit of having a preview code path is that when we stabilize it we can trivially retain the old code path to allow opt-in to legacy when we change the default, which would give us the signal we need for long-term removal.

Alas that lengthens the period of time in which we have two implementations for differentials :)

[woodruffw]

Yeah, I think I lean towards a preview feature here. I'll get this into a working shape and then massage the old tokio-tar paths back into place.

[astral-sh-bot]

uv test inventory changes

This PR changes the tests when compared with the main base revision.

• Added tests: 18
• Removed tests: 0
• Changed suites: 3

uv-build-backend: +1 / -0

Added:

• uv-build-backend::tests::built_by_uv_building_tar_codec

Removed: none

uv-extract: +14 / -0

Added:

• uv-extract::stream::tests::strict_decoder_rejects_excluded_tar_framing
• uv-extract::stream::tests::strict_decoder_rejects_non_utf8_member_names
• uv-extract::stream::tests::tar_http_errors_are_detected_through_the_source_chain
• uv-extract::stream::tests::untar_preserves_archive_owned_and_missing_symlink_targets
• uv-extract::stream::tests::untar_reads_gnu_archives
• uv-extract::stream::tests::untar_records_files_and_preserves_executable_intent
• uv-extract::stream::tests::untar_rejects_ambient_symlink_targets
• uv-extract::stream::tests::untar_rejects_external_symlink_targets
• uv-extract::stream::tests::untar_rejects_hardlinks
• uv-extract::stream::tests::untar_rejects_malformed_archives
• uv-extract::stream::tests::untar_rejects_member_path_traversal
• uv-extract::stream::tests::untar_selects_backend_from_preview_feature
• uv-extract::stream::tests::untar_skips_symlinks_on_windows
• uv-extract::stream::tests::untar_uses_default_name_validation

Removed: none

uv-publish: +3 / -0

Added:

• uv-publish::tests::source_dist_pkg_info_reads_single_top_level_file
• uv-publish::tests::source_dist_pkg_info_rejects_duplicates
• uv-publish::tests::source_dist_pkg_info_requires_a_file

Removed: none

[woodruffw]

astral-sh/tar-codec#103