[QGIS-Developer] Select/extract by location algorithm with same input layers (un)expected results?

[DelazJ]

Hi,
I don't know whether it's an issue to file or a design so i'm asking
beforehand.

If you use select by location algorithm with the same layer as source and
comparing, and select a predicate like "within" for example, it returns all
the features since it considers a feature to be within itself. Logical but
this means that you can not rely on this tool to check whether there are
features in the same layer that are within others.
This applies to most of the other geometric predicates, making them useless
in this context.

Question: Should the algorithm not skip same features comparison when we
use the same data source? Or are there other tools for features comparison
if the layers are the same?

Regards,
Harrissou
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