Add additional deprecation support

[aidandj]

This generates properties instead of attributes for methods, enum values, message fields and adds deprecation decoration if the option is set.

[Copilot]

Pull request overview

This PR enhances deprecation support in the mypy-protobuf plugin by generating properties instead of attributes for deprecated protobuf elements, allowing proper deprecation warnings to be surfaced through type checking.

Key changes:

• Deprecated message fields, gRPC methods, and enum values are now generated as properties with @deprecated decorators
• This enables mypy to catch usage of deprecated elements at type-check time
• Test expectations updated to reflect 9 additional deprecation warnings (from 105 to 114 errors)

Reviewed changes

Copilot reviewed 24 out of 27 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
test_negative/output.expected.*	Updated expected mypy error counts and line numbers to reflect new deprecation warnings
test_negative/negative.py	Added test cases for deprecated fields, methods, and enum values
test/test_generated_mypy.py	Updated error count assertion from 90 to 96
test/generated_concrete/testproto/test_pb2.pyi	Generated deprecated message fields as properties with deprecation decorators
test/generated_concrete/testproto/grpc/dummy_pb2_grpc.pyi	Generated deprecated gRPC methods as properties with deprecation decorators
test/generated_concrete/testproto/grpc/dummy_pb2.pyi	Generated deprecated request fields as properties with deprecation decorators
stubtest_allowlist.txt	Updated allowlist for properties that don't exist at runtime
run_test.sh	Added logging for stubtest execution
proto/testproto/test.proto	Added deprecated field definitions for testing
proto/testproto/grpc/dummy.proto	Added deprecated method definitions for testing
CHANGELOG.md	Documented the new deprecation property generation feature

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[nipunn1313]

nice feature!

[nipunn1313]

I suppose - this is the kind of feature that might break on some corner case that we didn't anticipate. If there are any large .proto codebases out in the wild we could try it on, that could help give some confidence

[aidandj]

I suppose - this is the kind of feature that might break on some corner case that we didn't anticipate. If there are any large .proto codebases out in the wild we could try it on, that could help give some confidence

I asked for some input in issues and haven't heard, I'll do some more looking tonight. I added all the Google protobuf protos as a test, but they don't use my deprecation.

At first I changed them all to properties, but to minimize the blast radius I did it only for deprecated objects.

I know of a few large protobuf projects, but finding one that uses mypy protobuf, is fully static typed has been more challenging.