InMemory provider deletes wrong entry when DELETE and ADD for same PK

[dtkujawski]

Description

When using the InMemory provider, DELETING and ADDING entities with the same PK in the same SAVE operation will cause a concurrency violation (if concurrency is turned on). This is happening because the InMemoryStore class is deleting the wrong entity.

See fork for fix and unit test code: https://github.com/dtkujawski/efcore/tree/InMemorySharedEntry
Commit: dtkujawski@9e9c7f3

Example Code

  //seed context with a single record         
  context.Add(new Record { Key = "KEY", Concurrency = new DateTime(2021, 1, 1, 1, 1, 1) });
  context.SaveChanges();

  //mark existing record as "deleted" in change tracker
  context.Records.RemoveRange(context.Records);

  //insert new record with same key as being deleted
  context.Add(new Record { Key = "KEY", Concurrency = new DateTime(2021, 2, 2, 2, 2, 2) });

  //save (should delete 1st record and add second record) - throws Concurrency exception
  context.SaveChanges();

Root cause

I believe the issue is here:

efcore/src/EFCore.InMemory/Storage/Internal/InMemoryStore.cs

Lines 176 to 184 in 86a6983

	if (entry.SharedIdentityEntry != null)
	{
	if (entry.EntityState == EntityState.Deleted)
	{
	continue;
	}
	table.Delete(entry);
	}

Instead of table.Delete(entry); I believe it should be table.Delete(entry.SharedIdentityEntry);

Stack traces

Message: 
    Microsoft.EntityFrameworkCore.DbUpdateConcurrencyException : Conflicts were detected for instance of entity type 'Record' on the concurrency token properties {'Concurrency'}. Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLogging' to see the conflicting values.
  Stack Trace: 
    InMemoryTable`1.ThrowUpdateConcurrencyException(IUpdateEntry entry, Dictionary`2 concurrencyConflicts) line 380
    InMemoryTable`1.Delete(IUpdateEntry entry) line 218
    InMemoryStore.ExecuteTransaction(IList`1 entries, IDiagnosticsLogger`1 updateLogger) line 183
    InMemoryDatabase.SaveChanges(IList`1 entries) line 77
    StateManager.SaveChanges(IList`1 entriesToSave) line 1101
    StateManager.SaveChanges(DbContext _, Boolean acceptAllChangesOnSuccess) line 1151
    NonRetryingExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded) line 49
    StateManager.SaveChanges(Boolean acceptAllChangesOnSuccess) line 1131
    DbContext.SaveChanges(Boolean acceptAllChangesOnSuccess) line 507
    DbContext.SaveChanges() line 468
    SharedIdentityEntryTest.Shared_identity_entry_delete_and_insert_with_concurrency() line 35

Version information

EF Core version: 5.0
Database provider: InMemory
Target framework: 5.0.9
Operating system: Windows
IDE: Visual Studio 2019 16.9.6