Fix generic ActiveJob signatures

[iamhaseebn]

Motivation

Generic ActiveJob subclasses currently generate bare job class references in perform_later signatures. Sorbet requires generic classes to include type arguments, so the generated RBI fails type checking.

Fixes #2233.

Implementation

• Detect generic ActiveJob subclasses using T::Generic === constant.
• Look up their non-fixed type members and use T.untyped for each generated type argument.
• Use the parameterized job type for both the callback parameter and the perform_later return type.
• Preserve existing signatures for non-generic jobs.

Tests

• Added regression coverage for jobs with one type member and multiple type members.
• Ran bundle exec bin/test spec/tapioca/dsl/compilers/active_job_spec.rb.
• Ran the complete suite: 821 tests, 3,190 assertions, 0 failures, 0 errors, 2 skips.
• Ran bundle exec bin/typecheck and bundle exec bin/style.
• Ran documentation, README, gem RBI, and shim verification checks.

[iamhaseebn]

I have signed the CLA!

[amomchilov]

Let's document this

Suggested change

	#: (String constant_name) -> String
	def generic_job_type(constant_name)
	# Resolves the constant name into a valid Sorbet type reference,
	# applying `T.untyped` for any unfixed generic type variables.
	#
	# @example
	# generic_job_type("StandardJob") # => "StandardJob"
	# generic_job_type("GenericJob") # => "GenericJob[T.untyped]"
	#: (String constant_name) -> String
	def generic_job_type(constant_name)

[iamhaseebn]

Thanks! I've added documentation for generic_job_type in 85766fa, including examples for standard and generic jobs. The focused ActiveJob spec, RuboCop, docs generation, and typecheck all pass.

[amomchilov]

Hey @iamhaseebn, that doc got lost in one of your subsequent commits.

Can you add it back, and tidy up the git history? I think most (all?) of this makes sense to squash down to just one commit.

[iamhaseebn]

Good catch, thanks - I've restored the documentation and squashed this down to one signed commit.

[paracycle]

Sorry, I realize type_name_of is a better name for the method, since it returns the proper Sorbet type name, instead of the constant name. Also, it is much safer to make it call qualified_name_of so that the names are anchored properly.

I think after this, I am good to merge. Thank you!

[paracycle]

Suggested change

	# Resolves a constant name into a valid Sorbet type reference,
	# Resolves a constant into a valid Sorbet type reference,

[paracycle]

Suggested change

	# generic_name_of(StandardJob) # => "StandardJob"
	# generic_name_of(GenericJob) # => "GenericJob[T.untyped]"
	#: (Module[top] constant) -> String?
	def generic_name_of(constant)
	# type_name_of(StandardJob) # => "::StandardJob"
	# type_name_of(GenericJob) # => "::SomeModule::GenericJob[T.untyped]"
	#: (Module[top] constant) -> String?
	def type_name_of(constant)

[paracycle]

Suggested change

	type_name = name_of(constant)
	type_name = qualified_name_of(constant)

[paracycle]

I don't think this test adds much value given the test below exists. Can we just name the test below "generates correct RBI file for a generic job" instead and remove this?

[paracycle]

Testing with multiple kinds of type members would be great:

Suggested change

	Input = type_member
	Output = type_member
	Input = type_member
	Fixed = type_member { { fixed: String } }
	Output = type_member { { upper: ActiveRecord::Base } }

[iamhaseebn]

Thanks! I've applied all five suggestions and pushed the update.