Correctly expand path variables for Update Methods.

[nullaus]

Refer to AIP-134 for more information.

Update Methods require the resource type name as the path parameter instead of a simple name (e.g. {vendor_contact.name=vendor_contacts/*} instead of {name=vendor_contacts/*})

This would case the following error to occur when generating an OpenAPIv2 specification:

panic: Path parameter "vendorContact.name" not found in path parameters

goroutine 1 [running]:
github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-openapiv2/internal/genopenapi.expandPathPatterns({0x14000798600?, 0x33?, 0x14000001b00?}, {0x14000b6a660?, 0x4?, 0x4?}, 0x14000001b00)

This was due to templateToParts applying the GetUseJSONNamesForFields flag and expandPathPatterns not factoring in JSON names when finding the path parameter by name in the slice of path parameters. It must look for the path parameter by JSON name.

Brief description of what is fixed or changed

I modified the find function to compare using JSON names when appropriate by looking at the UseJSONNamesForFields flag.

Also fixed are minor linter complaints when using go 1.23. I can omit these if preferred.

[johanbrandhorst]

LGTM

[nullaus]

Thank you for the ⚡ fast review @johanbrandhorst!

[johanbrandhorst]

I was actually surprised this passed without any generation changes. Do you think you could add a test to template_test that exercises this? Alternatively, add an annotation somewhere in one of our protobuf files that would exercise this. I think we should have one with user_json_names_for_fields set as an option. Thanks!

[nullaus]

@johanbrandhorst Here are the test cases that exercise this.

[johanbrandhorst]

Welp I missed it in the cosmetic changes, thanks for pointing it out

[nullaus]

No worries! Thanks again for your responsiveness. :)