Add stub for FormBuilderInterface::getForm() variadic params

[marklabrecque-ab]

Fixes #892.

Problem

In Drupal 10.x, FormBuilderInterface::getForm() uses a comment-style variadic parameter (/* , mixed ...$args */) rather than real PHP variadic syntax. PHPStan does not see the extra arguments and reports an error when calling getForm() with more than one parameter.

This has already been fixed in Drupal 11.x where the method signature uses proper mixed ...$args syntax.

Solution

Add a stub at stubs/Drupal/Core/Form/FormBuilderInterface.stub that declares the real variadic signature. The project's DrupalStubFilesExtension auto-discovers .stub files under stubs/, so no additional configuration is needed.

[mglaman]

I don't think stubs work this way, it only allows enhancing phpdoc and not the actual signatures

[mglaman]

Thanks for the contribution! Unfortunately this approach won't work — PHPStan stub files only override PHPDoc annotations, not native method signatures. The mixed ...$args variadic parameter added in the stub won't be recognized by PHPStan, so it won't resolve the false positive.

The root cause is Drupal 10's use of a comment-style variadic (/* , mixed ...$args */) instead of real PHP syntax. This was properly fixed in Drupal 11.x with a real variadic signature, so the issue doesn't exist there.

Given that Drupal 10 reaches end of life on December 9, 2026, we're going to close this without a fix. In the meantime, you can suppress the error with // @phpstan-ignore argument.count at the call site.