SaveChangesAsync Infinite Loop when Insert with DbUpdateException

[ubeyou]

Describe the bug
SaveChangesAsync Infinite Loop when DbUpdateException.
Only happens in AuditDbContext, DbContext can't reproduce the bug.

To Reproduce
Adding an entry with the same primary key & save changes.

Expected behavior
It should return DbUpdateException just like how It works on DbContext

Libraries (specify the Audit.NET extensions being used including version):

• Audit.NET: 13.1.2
• Audit.EntityFramework: 13.1.2

Additional context

1. I've tried to debug line by line, apparently the code itself loop back to the SaveChangesAsync.
   When first received an exception, it went into SaveScopeAsync
   

   Audit.NET/src/Audit.EntityFramework/DbContextHelper.cs

   Line 458 in 34280b9

   await SaveScopeAsync(context, scope, efEvent);

2. AuditScope.SaveAsync ()
   

   Audit.NET/src/Audit.EntityFramework/DbContextHelper.cs

   Line 147 in 34280b9

   UpdateAuditEvent(@event, context);

3. AuditScope.SaveEventAsync ()
   

   Audit.NET/src/Audit.NET/AuditScope.cs

   Line 340 in 929493b

   await SaveEventAsync();

4. await this._dataProvider.InsertEventAsync(this._event);
   

   Audit.NET/src/Audit.NET/AuditScope.cs

   Line 433 in 929493b

   _eventId = await _dataProvider.InsertEventAsync(_event);

5. await (auditDbContext as IAuditBypass).SaveChangesBypassAuditAsync()
   

   Audit.NET/src/Audit.EntityFramework/Providers/EntityFrameworkDataProvider.cs

   Line 161 in 09ca474

   await (auditDbContext as IAuditBypass).SaveChangesBypassAuditAsync();

6. int num = await base.SaveChangesAsync();
   

   Audit.NET/src/Audit.EntityFramework/AuditDbContext.cs

   Line 196 in f2264fe

   return await base.SaveChangesAsync();

step 6 will loop back to the SaveChangesAsync again & formed an infinite loop.

[thepirat000]

I was not able to reproduce exactly, but I've found a problem and I think that's the cause of the issue.

I'm assuming you use the EntityFrameworkDataProvider to save the audits on the same DbContext who has the audited entities. If this is not correct, please share your configuration and contexts.

Say you are saving a change on your context. If the change fails (i.e. DbUpdateException) then the framework still tries to save the audit before throwing the exception, but since you use the exact same context for saving audits, the audit saving fails because the context detects the previous change and try to re-apply it. Nevertheless I don't see why you are getting an infinite loop.

Fortunately you could workaround it by indicating the framework you want to create a new context instance for each audit operation, with the .UseDbContext<T>() extension on the configuration api.

For example :

Audit.Core.Configuration.Setup()
    .UseEntityFramework(_ => _
        .UseDbContext<YourContext>()    // <---- ADD THIS LINE 
        .AuditTypeExplicitMapper(m => m
            .Map<Blog, BlogAudit>()
            .Map<Post, PostAudit>()
            .AuditEntityAction<IAuditEntity>((ev, entry, entity) =>
            {
                entity.AuditAction = entry.Action;
                entity.Exception = ev.GetEntityFrameworkEvent().ErrorMessage;
            })));

I'm wondering if that should be the default behavior...

Note: I've added a unit test for this here

[ubeyou]

Thanks. It works after applied your workaround above.

Based on my observations, after applied the solution,
The second time it loop SaveChangesAsync, EntityFrameworkEvent will become null & it will stop right there. The infinite loop stopped due to new context.

Audit.NET/src/Audit.EntityFramework/DbContextHelper.cs

Line 444 in 34280b9

var efEvent = CreateAuditEvent(context);

[penihel]

I had the same problem.

But, when i used UseDbContext i had another problem. Because i use transactions with System.Transactions on dotnet core 2.2. Two instances of my DbContext throws this exception:

"This platform does not support distributed transactions."

So, i solved like this:

           
            Configuration.AddCustomAction(ActionType.OnEventSaving, scope =>
            {

                if (scope.Event.Environment.Exception != null)
                {
                    scope.Discard();
                }

            });
`

[Den4ikzxcv]

@penihel for me your way doesn't work, but worked this approach:

 Audit.Core.Configuration.Setup()
     .UseEntityFramework(_ => _
     .AuditTypeMapper(t => typeof(AuditLog))
     .AuditEntityAction<AuditLog>((ev, entry, entity) =>
     {
         // To fix audit infinity cycle in case of DbUpdateException
         if (ev.Environment.Exception != null)
         {
             return false;
         }
         ...
    }).IgnoreMatchedProperties(true));