Don't call MapDataWithEditsSource listeners if nothing changed

[Helium314]

fixes #4077

This is a longer version of what was linked in #4077 (comment), but it's not doing more work and I think it's easier to read that way.

[westnordost]

Some questions... also, should add tests as this is a critical section of code

Also:

but it's not doing more work and I think it's easier to read that way.

Thank you, yes!

[westnordost]

What should be tested:

• does not call onUpdated when all deleted elements are already deleted
• does not call onUpdated when all updated elements stayed the same
• does not call onUpdated when all updated elements stayed the same except for version and timestamp
• does call onUpdated when not all deleted elements are already deleted
• does call onUpdated when not all updated elements stayed the same

[westnordost]

In terms of numbers, I guess it is reasonable to claim 2x faster quest solving (with auto-sync on) and 2x faster upload times?

[Helium314]

I added the tests, but the last one fails.
I think this is because using mapDataChangesAre the changes are not actually edits applied on top of some initial elements... how do I do that?

[westnordost]

Uhm, not sure I understand the problem. But mapDataChangesAre is just a helper function. You can create a different helper function as you like you fix it if it does not do what one would expect.

[westnordost]

Maybe I ran into the same problem as you when adding tests to the now dismissed #4481 PR. Shouldn't you be able to use editsControllerNotifiesMapDataChangesAdded?

It simulatest that the EditsController notifies the MapDataWithEditsSource class about new changes that have been added.

[Helium314]

Thanks! editsControllerNotifiesMapDataChangesAdded and originalElementsAre made it work as intended.