UnnecessaryAbstractClass should report empty abstract classes

[severn-everett]

The rule UnnecessaryAbstractClass will not mark an abstract class that has no member declarations (e.g. abstract class Foo) as violating the rule. However, adding brackets to the class declaration (e.g. abstract class Foo{}) will trigger the rule. Semantically, these appear to be the same declaration, so UnnecessaryAbstractClass should be refactored to trigger in both scenarios.

[BraisGabin]

I checked the code of this rule and found that this exception was added on propouse. I found that it was added to fix #550. @schalkms, is there any reason for this?

[schalkms]

That was a long time ago. As far as I remember, this was added due to a clash with the EmptyClass rule.

[severn-everett]

Would you be able to elaborate about this? The NoEmptyClassBody rule doesn't have any specifications about whether it's an abstract class, which is what this rule would be specifically analyzing.

[schalkms]

If both rules are enabled, this snippet triggers both rules resulting in 2 reports.

[severn-everett]

How would this get reproduced? Running Detekt on abstract class Foo with both UnnecessaryAbstractClass and NoEmptyClassBody set to active on Detekt 1.19.0 doesn't trigger either issue.

[BraisGabin]

So, green light. @severn-everett can you create a PR fixing this?

[severn-everett]

Will do, after I work on another use case I discovered for PR #4353

[schalkms]

This was the case back then before detekt v1.0 got released. Quite some time passed since then. ☺️

[schalkms]

Closed by a9ce1e2