raise conflicts for variants with the same matcher

[samuelstroschein]

Context

This below should have been a conflict. I merged "viva la application" which has a different variant.id but the matcher is identical to meine coole app.

Reproduction

1. Open tis file in fink

   minimal-meine-coole-app.inlang

2. Merge this file into the first one

minimal-viva-la-application.inlang

[NilsJacobsen]

That feels like a validation rule topic? We allow adding two variants with the same matchers.

[samuelstroschein]

Good point. It could be solved with both. Solving it via a validation rule seems more generic

• if i work in a project and add a variant with the same matcher -> validation rule?
• if i merge your work -> conflict?

[NilsJacobsen]

How do we detect that as a conflict? Can we use validation rules to raise conflicts when merging? -> So only healthy states get through?

[samuelstroschein]

we can use validation rules but they are semantically different than conflicts. a conflict = unmergable. validation rule = mergable but you likely don't want that.

showing both while merging is prob what we should do