MySQL Bugs: #61729: Skip/Take Clauses Causes Null Reference Exception in 6.3.7 and 6.4.1 Only

Bug #61729	Skip/Take Clauses Causes Null Reference Exception in 6.3.7 and 6.4.1 Only
Submitted:	3 Jul 2011 15:06	Modified:	29 Sep 2011 20:20
Reporter:	Wenbin Xu	Email Updates:
Status:	Closed	Impact on me:	None
Category:	Connector / NET	Severity:	S2 (Serious)
Version:	6.3.7, 6.4.1 Beta	OS:	Windows (Windows XP SP3 / 7 SP1)
Assigned to:	Fernando Gonzalez.Sanchez	CPU Architecture:	Any
Tags:	.net Connector, 6.3.7, 6.4.1, entity framework

Description:
Symptom
-------
Execute LINQ to Entity query in 6.3.7 / 6.4.1 results in NullReferenceException. But the same code succeeds in 6.3.6.

How to repeat:
Steps to Reproduce
------------------
The problem happens in a big project and it is hard for me to upload a repro project/DB. However, I can describe the basics of what happens with pseudo code below.

1. var query = context.talents.Include("Gender");

2. query = query.Include("Industries");

3. query = query.Include("JobFunctions");

4. query = query.Where(...).OrderBy(...).ThenByDescending(...).Skip(0).Take(32);

5. query.ToList();

The exception happens at step#5. If I removed Skip/Take clause from step#4 or use 6.3.6 connector, then the execution succeeds.

Moreover, I'll upload the screenshot of exception to help isolate the problem.

Suggested fix:
Make code work the same as 6.3.6

NullReferenceException Screenshot # 1

Attachment: 1.png (image/png, text), 64.82 KiB.

NullReferenceException Screenshot # 2

Attachment: 2.png (image/png, text), 88.10 KiB.

Can you copy/paste the full stack trace when the exception occurs?
It is not very informative on the screenshot.

Stack Trace

Attachment: stack_trace.txt (text/plain), 5.40 KiB.

Is this a bug fix only in 6.3.7 / 6.4.1 or actually it solves a problem in upcoming 6.4.x releases?

Thank you for your bug report. This issue has already been fixed in the latest released version of that product, which you can download at

  http://www.mysql.com/downloads/

This has been fixed in releases 6.2.6, 6.3.8 & 6.4.4.

Added to changelog for 6.2.6, 6.3.8, 6.4.4: 

Executing a "LINQ to Entity" query could result in a
NullReferenceException error.