Add optional annotation in serialize step in codegen objective C output

[aladine]

Summary:

Added support for optional methods in Objective-C protocols. This change allows marking methods as optional in native modules by adding the optional property to method definitions. Optional methods are properly grouped under a single @optional directive in the generated protocol, improving code organization and readability. Note that in Objective-C, @optional directive will apply for all the subsequent methods in protocol block so we have to move all optional methods at the end. This is implemented by inserting optional/required marker in ProtocolMethodTemplate in intermediate processing step.

Changelog:

[IOS] [CHANGED] - Support optional methods in native module protocols

Test Plan:

Updated test case GenerateModuleHObjCpp-test.js.snap with optional methods to ensure they are properly marked with @optional in the generated protocol and grouped together in the output.

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[Hardanish-Singh]

LGTM!

[cipolleschi]

@aladine thanks for working on this.
I read through the code and it makes sense to me.

[cipolleschi]

@aladine can you fix the JS linter, please?

[aladine]

@cipolleschi : I just updated lint and snapshot tests.

[facebook-github-bot]

@cipolleschi has imported this pull request. If you are a Meta employee, you can view this in D78265319.

[aladine]

For the latest lint error https://github.com/facebook/react-native/actions/runs/15977428423/job/45918230480, I run prettier locally and it doesn't detect any lint problem.

[cipolleschi]

I run it locally. It applies this change in the serializeMethod.js file:

}>) =>
-  `${isOptional ? '@optional\n' : '@required\n'}- (${returnObjCType})${methodName}${params};`;
+  `${
+    isOptional ? '@optional\n' : '@required\n'
+  }- (${returnObjCType})${methodName}${params};`;
export type StructParameterRecord = $ReadOnly<{

[aladine]

Thanks Riccardo, I have fixed the lint based on your suggestion.

[cipolleschi]

how does this behave for Android? I know that the PR is only for iOS, but if we define an optional method, currently Android is forced to implement it, right?

[aladine]

That is a good question. For Android, the abstract method has a default no-ops implementation in generated class {} https://github.com/facebook/react-native/blob/main/packages/react-native-codegen/src/generators/modules/GenerateModuleJavaSpec.js#L117

If there is no implementation for optional method in Turbo class(which extends the generated spec class), it will fallback to the default no-ops block.

[cipolleschi]

this is a bit stuck internally.
This was the initial implementation for this feature, but then we decided not to use the @optional.

The vision here is to move to a subclass approach, but that would be a breaking change for the ecosystem. This needs more discussion, unfortunately.

[react-native-bot]

This PR is stale because it has been open 180 days with no activity. Remove stale label or comment or this will be closed in 7 days.

[react-native-bot]

This PR is stale because it has been open for 180 days with no activity. It will be closed in 7 days unless you comment on it or remove the "Stale" label.