Support advanced topology rules across layers

[FelixHinckel]

What is the bug or the crash? What were your expectations and what actually happened?

I have a two-layer project containing :

• a "habitat" polygon layer
• a "flore" polygon layer

Here are the rules I want my project to follow :

• "habitat" MUST NOT overlap itself
• "flore" CAN overlap itself
• "flore" CAN overlap "habitat" and vice-versa.

I have this setup in theQGis snapping advanced configurations, ensuring all rules are respected :

And this is the outcome on QField:

• "habitat" polygons don't overlap themselves ✔️
• "flore" polygons can overlap themselves ✔️
• "flore" polygons cannot overlap "habitat" polygons. ❌

I tried switching off snapping, topological editing, and layer snapping, whith the same effect.

I tried another snapping setting on QGis :

And now I have this outcome :

• "habitat" polygons don't overlap themselves ✔️
• "flore" polygons can overlap "habitat" polygons. ✔️
• "flore" polygons can not longer overlap themselves ❌

Again, I tried switching off snapping and topological editing in QField.

Is there a solution I am missing to activate/desactivate topological rules in QField? If not, is it something that can be implemented to allow this?

Steps to reproduce the issue

1. Open the linked projects settings1.zip settings2.zip

2. Verify the advanced snapping configuration (settings1 follow the first case, and setting2 the second)

3. Digitize overlaping polygons on both layers

Version

Android : 3.6.5 (used for testing)

Operating system name

Android

Operating system version

Android 14

Reinstall QField

• [x] I have a fresh install of the latest QField version, but the problem persists.
• [x] Problem can be reliably reproduced, doesn't happen randomly.
• [x] Problem happens with all files and projects, not only some files or projects.

Additional context

This problem has been found both on android and windows. I have used the windows version (not up to date) to make the screenshot more easily. They are conform with the visuals on android.

I have adressed an issue on QGis as well, asking whether a snapping configuration can tackle all of these rules at once. If this is answered, and transposed to QField, it can fix the problem too. https://github.com/qgis/QGIS/issues/62333

[nirvn]

@FelixHinckel , I've transformed this into an enhancement request.

[nirvn]

One relatively easy way to improve things here would be to have a toggle overlap (like we currently have for snapping and topological editing).