DO NOT MERGE: Smoke-test of a costly “always compute old-style IDs” approach

[mtrmac]

This is a variant of #24287 which reverts (some of) the system test changes to again expect old-style IDs, and includes containers/storage#2155 / containers/image#2613 .

⚠️ WARNING: all of this is a quick sketch, absolutely untested.

This exists purely to give us options. With this, zstd:chunked loses some of the performance wins, and it should revert to old-style IDs. We then have the option to reintroduce the ID change and performance improvement (perhaps even based on measurements) later.

And, separately, this enforces that layers should match against the config’s DiffIDs, resolving the signing ambiguity.

FYI @giuseppe @edsantiago @mheon @baude

Does this PR introduce a user-facing change?

None

[openshift-ci]

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[packit-as-a-service]

Ephemeral COPR build failed. @containers/packit-build please check.

[packit-as-a-service]

Ephemeral COPR build failed. @containers/packit-build please check.

[mtrmac]

Note to self: If/after containers/storage#2156 merges, this PR will need to re-enable enable_partial_images.

Edit: done.

[mtrmac]

The test images with all images converted to zstd:chunked are too old. For now I’m leaving that variant in https://github.com/mtrmac/libpod/tree/mitr-zstd-costly-old-ids-integration-chunked-test-images , and reverting to test with the current images here.

⚠️ That significantly decreases the scope of testing; many of the unexpected behavior changes were happening only with most images converted to zstd:chunked. With this, we are mostly back to the test coverage of #21903 , which is known to not demonstrate many of the surprises.

[edsantiago]

The test images with all images converted to zstd:chunked are too old

Would you care to follow (and test and review) my new simplified automation_images doc? You will need to import https://github.com/containers/automation_images/pull/388/files but apart from that it really should be fairly simple.

[mtrmac]

Thanks, I’ll definitely try that.