Cluster related bugs

[mihaibudiu]

A bug in a tested database can cause many different tests to fail.
There should be a way to cluster bugs that are likely due to the same underlying problem - e.g., based on the top of the stack trace.
This could be beneficial for:

• reporting purposes
• filing bugs against other databases
• ignoring known bugs that haven't been fixed yet

[julianhyde]

Maybe add a 'filter' mechanism. The filter is called with the executor name, file name and SQL text, and returns whether to skip the test, and/or modified SQL. Filters are orthogonal to executors.

[julianhyde]

This could have handled (worked around) the bug where HSQLDB considered '- -2' to be invalid, by converting this to '2'.

[mihaibudiu]

The filter would generalize the "bugsfile" (option -b).
The trouble is that to do this right you have to parse the query. Or write some regular expressions to account for the number of spaces. There may be other patterns to look for, like "- + 2".

[julianhyde]

Whether to parse or use regex is up to the implementation of the filter. The typical filter will have a few regexes, but won't parse the query.

[mihaibudiu]

I have filed #21 for this feature.