Detect removing an enum value (without removing the whole enum) as a breaking change

[melinath]

What kind of contribution is this issue about?

Pull request UX

Details

Removing an enum value (even UNSPECIFIED values) is unsafe and shouldn't happen outside a major release.

References

No response

[ScottSuarez]

This is going to be very to difficult to support. The breaking change detector works off the Provider Schema directly.

Enum fields aren't natively supported on the schema and are manually implemented through validation functions. Thus this item would require much more work at either:

• parsing AST (dubious)
• diffing mmv1 schemas (needs new implementation)

[ScottSuarez]

Parsing AST could work if we git diff the LOC on the validation functions. t-shirt size may be smaller in that case

[melinath]

This might be easier to do for plugin-framework resources, since (I think?) we could represent enums as a "custom type": https://developer.hashicorp.com/terraform/plugin/framework/handling-data/types/custom (which would mean they could include Values as a part of the schema instead of us needing to parse the AST)