Gossip: rm deprecated messages

[alexpyattaev]

Problem

• Several messages in gossip are deprecated, but their parsers still exist

Proposed Solution

• Slap stable-abi onto the gossip structs, making sure only non-deprecated variants are instantiated
• Remove dead legacy variants

[illegalcall]

Implemented stable-abi coverage and stopped emitting deprecated gossip variants, while keeping legacy parser slots for wire compatibility. Does this look good, and is this complete for #10333 or just part of it?

[alexpyattaev]

1. we need stable-abi, not just frozen-abi. the naming of froze-abi is unfortunate, but it actually does enforce api compatibility more so that abi. Adding stable-abi should be the only thing the first PR does, nothing else. To test whether it works there is a script ./ci/test-frozen-abi.sh that actually runs abi check tests.
2. once stable-abi is added to the code we can get to removal, not before. Only once stable-abi support is merged can we start removing the dead variants, and we may want to take it slow and remove a couple of variants at a time to keep the diff sizes manageable. Each time we remove legacy variant, the api_digest would change, but abi_digest should not.

[illegalcall]

Thanks for clarifying.

I’ll rescope #10463 to stable-abi only: add frozen_abi digest coverage for gossip types and validate with ABI tests. I’ll remove deprecated-variant cleanup and unrelated changes from this PR.
After this lands, I’ll do follow-up PRs to remove legacy variants incrementally.

Hope this sounds good?

[alexpyattaev]

Hope this sounds good?

Yes. you can also probably repurpose some of the code required for stable_abi to work (for impl Distribution) from #4880

[illegalcall]

Hey @alexpyattaev , I've updated the PR to be stable-abi only as you suggested.

Changes:

• Added frozen_abi(digest) coverage to Protocol, PruneData, CrdsData, CrdsValue, CrdsFilter, and ContactInfo
• Added necessary frozen-abi feature dependencies for transitive types
• Removed all behavioral changes (no deprecated variant removal, no test modifications)

Validation:

./ci/test-frozen-abi.sh

All 6 gossip frozen-abi tests pass.

Once this lands, I'll follow up with incremental PRs to remove deprecated variants one at a time as you recommended.