[QGIS-Developer] Message "The operation would change the geometry type." ?

[Richard Duivenvoorde]

Hi Devs,

A friend, while editing a vector layer, got the message: "The operation would change the geometry type." while editing a 'standalone' layer, and asked me what it was...

Today somebody in the Telegram channel asked the same.

I grepped:
https://github.com/qgis/QGIS/blob/master/src/app/vertextool/qgsvertextool.cpp#L2410

which points to:
https://github.com/qgis/QGIS/blob/master/src/core/geometry/qgsgeometry.h#L2401-L2414

but what I'm trying to find out is what kind of test QGIS is doing in the vertextool, if you do not have any relations in your project (or at least are not aware of it...)

cpp docs tell me: "Modifies geometry to avoid intersections with the layers specified in project properties"
But I cannot find something with 'avoid' or 'intersection' in my Project properties.

So question: is this a message which should not be there (because it pops up at people which are not aware of anything).
Or is there a property on True by default which make QGIS do tests, even on 1 layer?

Thanks for any input,

Richard Duivenvoorde