[bugfix] Fix georeferencer crash when deleting a point through context menu #18227

[alexispolti]

Description

fixes #18227
Georeferencer crashes when deleting a point through context menu. This should fix it.

Checklist

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[alexispolti]

Any news @nyalldawson ?

[alexispolti]

@m-kuhn or anyone: is there something beside lack of time preventing merge ? :-)

[m-kuhn]

@m-kuhn or anyone: is there something beside lack of time preventing merge ? :-)

Nope, that's it pretty much :)

Looks ok to me to change it this way, but I'm not sure what caused the original crash. Was it that mPrevRow pointed to an invalid row or something else?
If it's the the invalid mPrevRow, will the crash appear again if you first recenter on this point and then delete it after?

[alexispolti]

Yes, mPrevRow / mPrevColumn were positioned on the selected point whether the action was "Recenter" or "Delete point". Which in the second case leads obviously to a crash as they pointed to a non existing row/column. The fix is to change them only when the action is "Recenter".
We could first recenter on the point, then delete it but IMHO it would be more confusing than helping: when you select a point to delete it, you already know which one it is (if not, you first select "Rencenter"). So is it really necessary to center on a now-non-existing point?

[m-kuhn]

You are right of course, I meant to ask something different. Let me reformulate my question. If a user first clicks recenter (mPrevRow/mPrevColumn are set) and then he clicks delete, will this also crash or are mPrevRow/mPrevColumn invalidated with some other functionality in this scenario?

[alexispolti]

(Sorry, ashamed of my poor English)
No, there won't be any crash, as mPrevRow is only used in updateItemCoords which cannot be called as the point doesn't exist anymore.

[m-kuhn]

Thanks a lot!

[alexispolti]

Thanks to you!