Bug #84453 Exception caused by Skip & Take in MySQL EF Core

• Submitted: 10 Jan 2017 6:11
• Modified: 9 Feb 2017 21:00
• Reporter: Charlie Chu (OCA)
• Status: Closed
• Category: Connector / NET
• Severity: S2 (Serious)
• Version: 6.10.0
• OS: Any
• CPU Architecture: Any

[10 Jan 2017 6:11] Charlie Chu

Description:
MySql.Data.MySqlClient.MySqlException: Undeclared variable: __p_1
   at MySql.Data.MySqlClient.MySqlStream.ReadPacket()
   at MySql.Data.MySqlClient.NativeDriver.GetResult(Int32& affectedRow, Int64& insertedId)
   at MySql.Data.MySqlClient.Driver.NextResult(Int32 statementId, Boolean force)
   at MySql.Data.MySqlClient.MySqlDataReader.NextResult()
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
   at System.Data.Common.DbCommand.ExecuteDbDataReaderAsync(CommandBehavior behavior, CancellationToken cancellationToken)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MySql.Data.EntityFrameworkCore.Storage.Internal.MySQLRelationalCommand.<ExecuteAsync>d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.EntityFrameworkCore.Query.Internal.AsyncQueryingEnumerable.AsyncEnumerator.<MoveNext>d__8.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.EntityFrameworkCore.Query.Internal.AsyncLinqOperatorProvider.ExceptionInterceptor`1.EnumeratorExceptionInterceptor.<MoveNext>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.<ToListAsync>d__129`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at PaginatedList`1.<CreateAsync>d__13.MoveNext() in /Users/CharlieChu/**.cs:line 39
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at MyFirstApp.Controllers.UserController.<Index>d__2.MoveNext() in /Users/CharlieChu/**.cs:line 87
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeActionFilterAsync>d__28.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeAsync>d__18.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Builder.RouterMiddleware.<Invoke>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.<Invoke>d__6.MoveNext()

How to repeat:
MySqlException: Undeclared variable: __p_1
ReadPacket

        var items = await source.Skip((pageIndex - 1) * pageSize).Take(pageSize).ToListAsync();

[10 Jan 2017 6:57] Chiranjeevi Battula

Hello Charlie Chu,

Thank you for the bug report.
Could you please provide repeatable test case (exact steps - please make it as private if you prefer) to confirm this issue at our end?

Thanks,
Chiranjeevi.

[9 Feb 2017 21:00] Christine Cole

Fixed as of the upcoming MySQL Connector/NET 6.10.1 release, and here's the changelog entry:

EF Core: Using the Skip and Take methods in an assignment generated an
exception.

Thank you for the bug report.

[29 Jun 2017 1:35] S Vassil

This is not fixed. The bug is still present in the latest .Net connector code. I have installed and tried it with connectors 6.10.1 and even the 7.x connectors. 

For me it says 'Undefined variable: __p_2' when ever I have a Take() method call with EF Core and the MySQL provider. As soon as I remove the Take() call the whole query works.

This out of all the bugs with EF Core is probably the most urgent for us because it breaks a large majority of our application.

Using Dependencies:

MySql.Data.EntityFrameworkCore (7.0.7-m61)
MySql.Data.EntityFrameworkCore.Design (6.10.1-beta)
Microsoft.EntityFrameworkCore.Tools (1.1.1)
Microsoft.EntityFrameworkCore.Design (1.1.2)