feat(26.04): introduce v3 format - #903

i know this is still in draft mode, but i thought i'd have a look anyway

syntax errors in: EDIT: fixed while i was posting the review, but the bit below is still valid

- slices/libpython3.13-stdlib.yaml
- slices/libsnappy1v5.yaml
- slices/libsubid5.yaml
- slices/libtiff6.yaml
- slices/libvdpau1.yaml
- slices/mesa-libgallium.yaml
- slices/perl-base.yaml
- slices/rabbitmq-server.yaml
- slices/tar.yaml
- slices/util-linux.yaml

also, i'd fix those too, just so people are not confused when they find them in the comments:

$ find slices -type f -name '*.yaml' | xargs grep -nEH '\s{6}#\s-\s[^\s-]'
slices/rabbitmq-server.yaml:26:      # - erlang-base_bins
slices/rabbitmq-server.yaml:27:      # - erlang-inets_scripts
slices/rabbitmq-server.yaml:28:      # - erlang-inets_modules
slices/rabbitmq-server.yaml:29:      # - erlang-os-mon_bins
slices/nginx.yaml:11:      # - iproute2_bins
slices/libsubid5.yaml:14:      # - libcrypt1_libs
slices/libsubid5.yaml:15:      # - libpam0g_libs
slices/libsubid5.yaml:17:      # - libsemanage2_libs
slices/gcc.yaml:14:      # - gcc (priority 20)
slices/gcc.yaml:15:      # - clang (priority 10)
slices/gcc.yaml:16:      # - tcc (priority 10)
slices/gcc.yaml:17:      # - pcc (priority -100)
slices/openssl-provider-legacy.yaml:10:      # - libssl3t64_libs # prevent circular dependency with libssl3t64
slices/libboost-coroutine1.83.0.yaml:11:      # - libgcc-s1_libs
slices/ca-certificates-java.yaml:13:      # - openjdk-8-jre-headless_security

approving subject to CI passing and https://github.com/canonical/chisel-releases/pull/903/files#r2832716434 ( i've missed one case in my sed suggestion )

i have convinced myself with #927 that this PR is not introducing any new test failures, so +1 ( and let's fix the tests 💀 )

Comparing with #927 and looking at the previous commit it seems everything that's intended to pass is currently passing, so I'll give it a +1

ok. no, pause. i've dug into diff between here and #927 and there are some things i cannot quite explain.

why is for example zstd failing in this PR, but not in 927? i've run a manual test (sudo chroot rootfs /usr/bin/pzstd -h) on canonical/ubunutu-26.04 and on cjdcordeiro:v3 and its a reproducible difference! i've used chisel 1.4.0 for both.

i've tracked it down to missing lib -> usr/lib symlink when cutting this PR

here is the asciinema recording where i've run tree -C | head on the rootfs to show the missing symlink

• rec.txt
• https://asciinema.org/a/f3oXUBVxa4PK9KlU (play with asciinema play rec.txt)

if i, in addition to zstd_bins cut base-filed_lib which is normally where that symlink comes from, all is good.

obv i'd like to understand what's happening here before proceeding

Pull request overview

Introduces Chisel “v3” release format and migrates slice definitions to the v3-style dependency mapping.

Changes:

• Bumps chisel.yaml format from v2 to v3.
• Converts essential: dependency lists from sequences to maps across many slice YAMLs.
• Updates some slice definitions that previously used v3-essential to now use v3 essential mappings.

Reviewed changes

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ok. tests looking much better. some small diffs from #927 but i've tracked them down to:

• flaky openjdk tests
• archive issues in tests #743
• flaky python3-pyftpdlib tests

Looks good after a manual scrolling through all the changes.