Automatic test case reduction

It would be great to implement test case reduction strategies in SQLancer itself. The advantage of doing this in SQLancer, rather than an external tool like C-Reduce, is that we have all the information on whether a specific bug is still triggered (e.g., that two queries should yield the same result) and that the reduction can likely go further than when having an external interestingness test (e.g., since a predicate in the WHERE condition of two queries can be reduced simultaneously).

See:

• https://en.wikipedia.org/wiki/Delta_debugging
• https://embed.cs.utah.edu/creduce/

[oraluben]

• I have tried to run the branch you provided, but the FoundBugException is never thrown, since the execution is always failing before an actual bug is discovered due to a SQLite exception: org.sqlite.SQLiteException: [SQLITE_ERROR] SQL error or missing database (near "NULLS": syntax error). Is there a way that you know to avoid this, for example using a different version of SQLite? I have noticed that with version 3.36 this error is not thrown.

Maybe give --test-nulls-first-last=false a try?

[mrigger]

If you still have some time, the most useful thing would be to write the reduced test cases to a file, perhaps in a log-reduced directory adjacent to the current log directory.