QgsVectorLayer: add addMultiRing and use it in QgsMapToolAddRing

[lbartoletti]

Description

The QgsMapToolAddRing adds a ring through the addRing method of QgsVectorLayerEditUtils called by this of QgsVectorLayer.

The bug described in #23113 indicates that only one of the entities receives the ring addition when using the map tool.

This is consistent with the documentation of the addRing methods. So, it is by design that the tool works like this.

However, as stated in the ticket, it is best to add the ring to all entities.

In order to avoid an api break, I added a new addMultiRing method that adds the ring on all entities.

Fixes #23113

recording_2022-10-03-161557.mp4

[nyalldawson]

Got some unit tests coming too?

[uclaros]

I don't really like the addMultiRing() name, it kind of implies adding a MultiRing, if there is such a thing.
Imho, the old behavior is buggy and should be fixed on the existing methods. Is there a use case where the old only add a ring to a random intersecting polygon would be needed?

[lbartoletti]

I don't really like the addMultiRing() name, it kind of implies adding a MultiRing, if there is such a thing.

hmmm right, what's your suggestion?

Imho, the old behavior is buggy and should be fixed on the existing methods.

It was by design, and can't be fixed without an api break.

Is there a use case where the old only add a ring to a random intersecting polygon would be needed?

Personally, I don't know.

[uclaros]

How about addRingV2()?

Also, a test case for "selected features only" would be nice

[lbartoletti]

How about addRingV2()?

Also, a test case for "selected features only" would be nice

Done, thanks.

[qgis-bot]

The backport to queued_ltr_backports failed:

The process '/usr/bin/git' failed with exit code 1

stderr

error: could not apply b09c2d1132... QgsVectorLayer: add addMultiRing and use it in QgsMapToolAddRing
hint: After resolving the conflicts, mark them with
hint: "git add/rm <pathspec>", then run
hint: "git cherry-pick --continue".
hint: You can instead skip this commit with "git cherry-pick --skip".
hint: To abort and get back to the state before "git cherry-pick",
hint: run "git cherry-pick --abort".

stdout

Auto-merging python/core/auto_generated/vector/qgsvectorlayer.sip.in
Auto-merging src/app/qgsmaptooladdring.cpp
CONFLICT (content): Merge conflict in src/app/qgsmaptooladdring.cpp
Auto-merging src/core/vector/qgsvectorlayer.cpp
Auto-merging src/core/vector/qgsvectorlayer.h

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-queued_ltr_backports queued_ltr_backports
# Navigate to the new working tree
cd .worktrees/backport-queued_ltr_backports
# Create a new branch
git switch --create backport-50447-to-queued_ltr_backports
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick b09c2d113232ca1b4c5cc1e6be8cd5ad372f5019,6ebb15db9c937b73b46727fe98e31903ffd360a3,992e2bf1dfec13291f13b59a266dd54b41e5d05d,5d7a0253040243f85c5f6e17b6bf40dea758c69c,6a1222f187f68e250139cbf44add069ae4077cc4,cc07d1e7772e868779c76f947b6fccfadb6a198a,732be4999a00b927e0fd8deee4212724564add5b,e3bf816f55b4b52aeca0e3bcade04aac0dc5f132,2cede134edd84d69b86016eee97b2ca332af547d
# Push it to GitHub
git push --set-upstream origin backport-50447-to-queued_ltr_backports
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-queued_ltr_backports

Then, create a pull request where the base branch is queued_ltr_backports and the compare/head branch is backport-50447-to-queued_ltr_backports.

[nyalldawson]

@lbartoletti looks like this has introduced a flaky test -- see eg #50597