Add CSR breaking rules category

[doriable]

This adds a new breaking change detection category, CSR,
for the rules we run for CSR compatibility checks:

WIRE_JSON // entire category

ENUM_NO_DELETE
ENUM_VALUE_NO_DELETE
EXTENSION_MESSAGE_NO_DELETE
FILE_NO_DELETE
FIELD_NO_DELETE
FIELD_SAME_TYPE
FILE_SAME_SYNTAX
MESSAGE_NO_DELETE
MESSAGE_NO_REMOVE_STANDARD_DESCRIPTOR_ACCESSOR
ONEOF_NO_DELETE

Fixes BSR-2296

[github-actions]

The latest Buf updates on your PR. Results from workflow Buf CI / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Apr 21, 2025, 8:49 PM

[bufdev]

Is FILE_NO_DELETE correct?

[doriable]

Is FILE_NO_DELETE correct?

Yeah -- it's in the docs and also I double-checked the server-side implementation.

[andrejgou]

Hi there, thank you for developing such a great tool for the Protobuf ecosystem. I'm curious how we determined these rules for the new CSR category?

Yeah -- it's in the docs and also I double-checked the server-side implementation.

That link redirects to https://buf.build/docs/bsr/csr/#csr-policy-check but neither that page nor any of the pages under https://buf.build/docs/bsr/checks mention anything about particular rules. I don't have access to BSR's source code so I can't reference that either.

[doriable]

Appreciate the compliments, hopefully I am able to address your questions below :)

I'm curious how we determined these rules for the new CSR category?

So we went through the compatibility checks in the Confluent Schema Registry and referenced them against our breaking change detection rules to determine which rules we should use to enforce compatibility for use with the CSR.

That link redirects to https://buf.build/docs/bsr/csr/#csr-policy-check but neither that page nor any of the pages under https://buf.build/docs/bsr/checks mention anything about particular rules.

The page I was referencing in the comment contained the list implemented in this PR before this category was created, and the docs have been updated since, apologies for the confusion! Our full list of breaking change rules and categories is available here.