[OptionalUnit] Allow a function to declare a Unit return type when it uses a generic function initializer

[severn-everett]

This addresses issue #4363.

[severn-everett]

No idea why this is in a JavaScript package, but it appears to work in JVM code.

[codecov]

Codecov Report

Merging #4371 (cc5c1f2) into main (92433ea) will increase coverage by 0.02%.
The diff coverage is 70.00%.

@@             Coverage Diff              @@
##               main    #4371      +/-   ##
============================================
+ Coverage     84.26%   84.29%   +0.02%     
- Complexity     3263     3275      +12     
============================================
  Files           473      473              
  Lines         10336    10340       +4     
  Branches       1827     1830       +3     
============================================
+ Hits           8710     8716       +6     
  Misses          667      667              
+ Partials        959      957       -2     

Impacted Files	Coverage Δ
...rbosch/detekt/rules/style/optional/OptionalUnit.kt	85.96% <70.00%> (+4.83%)	⬆️

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[severn-everett]

@BraisGabin I'm not sure what I'm supposed to do here. CodeCov is requiring that I write a test where one of the two lines below returns a null value:

        val isGenericType = getResolvedCall(bindingContext)?.getReturnType()?.isTypeParameter() == true
        val isNothingType = getType(bindingContext)?.isNothing() == true

Otherwise, the PR is not hitting the target rate of 80% code coverage. The problem is that writing that test would require creating a code snippet where, for example, the function initializer isn't recognized (e.g. fun foo(): Unit = unknownFun { }). However, doing that will fail the compile-test-snippets step, because as the function initializer isn't recognized, the code wouldn't compile IRL. Any ideas on how to write a credible test here that will satisfy both codecov/patch and Pre Merge Checks / compile-test-snippets?

[BraisGabin]

@BraisGabin I'm not sure what I'm supposed to do here. CodeCov is requiring that I write a test where one of the two lines below returns a null value:

        val isGenericType = getResolvedCall(bindingContext)?.getReturnType()?.isTypeParameter() == true
        val isNothingType = getType(bindingContext)?.isNothing() == true

Otherwise, the PR is not hitting the target rate of 80% code coverage. The problem is that writing that test would require creating a code snippet where, for example, the function initializer isn't recognized (e.g. fun foo(): Unit = unknownFun { }). However, doing that will fail the compile-test-snippets step, because as the function initializer isn't recognized, the code wouldn't compile IRL. Any ideas on how to write a credible test here that will satisfy both codecov/patch and Pre Merge Checks / compile-test-snippets?

Don't care about that. If the tests really cover the main logic it's enough. If you check you are under the target but even with that you are increasing the coverage.