I normally don’t write such posts, but this time I’ll do a little whining. I was looking at MySQL’s Bug#69581, which was also filed against MariaDB as MDEV-5102. With some effort (little for this particular bug), one can find out that Bug#69581’s counterpart in Oracle’s internal bug database is Bug#16862316, and the fix is in revision 5366 in MySQL 5.6.14.
There are two problems, though:
- The fix doesn’t include a testcase. We know, Oracle doesn’t publish testcases for crashing bugs, with a justification that it’s for security reasons. However, this bug is not a crashing one. I’m wondering what was the justification for not including testcase for it?
- Luckily, the bug entry at bugs.mysql.com has the testcase, so I was able to play with it. As a result, I have found that MySQL’s fix is incomplete, and filed another bug, Bug#70703.
I think, the poor bugfix made by Oracle is not a big deal. Although, this is not the first time we at MariaDB see a poor bugfix by Oracle (Can the forks keep up? Well, they would, if they could trust upstream’s patches and just copy them, without having to check whether the fixes are real fixes or band-aids).
The lack of testcases is a much bigger concern. Has Percona Server merged fix for MySQL Bug#69581 correctly? Well, they don’t have any features related to partitioned tables, so most likely, the answer is Yes. But won’t it be nicer if mysql-test test suite had a testcase for this, and they could check it by running tests? It’s not only about forks/branches. Everybody who changes MySQL/MariaDB/Percona source code benefits from mysql-test testsuite having a good test coverage.
Now, are there any volunteers who could run through MySQL 5.6 changelog and find out whether missing testcase for non-crashing bug was an isolated occurrence, or it is a new trend?
Sergei Petrunia's blog 