[mrigger]

Thanks! Here is one interesting example of a bug that was reported on the SQLite mailing list: https://www.mail-archive.com/[e-mail].... The SQL query that triggers the bug is rather complex. Interestingly, it was generated automatically: "I might not spell it like that myself, but a code generator would do it (and much worse!). This example was simplified from a query generated by a Django ORM queryset using `.exclude(nullable_joined_table__column=1)`, for instance."

When the user reported the bug, it had actually already been fixed on the latest SQLite3 trunk based on one of our bug reports. The query in our test case used a “NOT NULL NOT NULL” predicate, which is unnecessary complex as well: https://www.sqlite.org/src/tktview?name=c31034044b. We believe that this is interesting evidence that even “obscure” bugs matter in practice, for example, when the queries are automatically generated, as demonstrated above.