The method Schema::indexExists() does not work for unique indexes in PostgreSQL

Indexes are created via Schema::addIndex() and have suffix __idx. The Schema::indexExists() checks only for indexes created via Schema::addIndex() (and it checks pg_indexes).

Unique keys are created as constraints via Schema::addUniqueKey() and have suffix __key. There is a Schema::constraintExists() which checks for PK, FK, UK (and it checks pg_constraint).

It is true, that pg_indexes contains records for PK, UK, .., but I am not sure (when using our terminology - index vs unique key) if the Schema::indexExists() should check for unique keys. Now it is separated in two functions - one for indexes, one for constraints. Otherwise would not be the Schema::constraintExists() redundant?

From older PostgreSQL docs - https://www.postgresql.org/docs/9.4/indexes-unique.html:

The use of indexes to enforce unique constraints could be considered an implementation detail that should not be accessed directly.

We are creating UK as constraints and despite the fact that there is an index created in the background, should not we treat them as constraints?

Is there a reason why the current behavior is a bug and what problems is this behavior causing (would be great to update IS with these information)? Thanks!