Suggestion. Use a stable sorting algorithm

[mikhail-khalizev]

Suggestion. Use a stable sorting algorithm when forming the sequence of command for insert and updating entities.

https://github.com/dotnet/efcore/blob/main/src/EFCore.Relational/Update/Internal/CommandBatchPreparer.cs#L81

- independentCommandSet.Sort(_modificationCommandComparer);
-
- var batch = _modificationCommandBatchFactory.Create();
- foreach (var modificationCommand in independentCommandSet)
+ var independentCommandSetSorted = independentCommandSet.OrderBy(x => x, _modificationCommandComparer);
+
+ var batch = _modificationCommandBatchFactory.Create();
+ foreach (var modificationCommand in independentCommandSetSorted)

[mikhail-khalizev]

This change allows to solve #11686

[AndriySvyryd]

Did you perform any testing that would show that this change would make any difference?

However, even if it would, the order in which the modification commands are in after the topological sort doesn't necessarily reflect the order of the items in the collection navigations.

Instead https://github.com/dotnet/efcore/blob/ac2bb48b10ecf1289b568a94b7a35e8075c6d787/src/EFCore.Relational/Update/Internal/ModificationCommandComparer.cs should be changed to compare keys on inserted entities too. This will reflect the order in which they were added to the change tracker, which should be closer to what is expected in #11686

[mikhail-khalizev]

Yes, I did some testing, this change works.

But your approach (change ModificationCommandComparer) will be better.