bpo-44859: Raise more accurate exceptions in sqlite3

[erlend-aasland]

Improve exception compliancy with PEP 249

• Raise InterfaceError instead of ProgrammingError for SQLITE_MISUSE.
  If SQLITE_MISUSE is raised, it is a sqlite3 module bug. Users of the
  sqlite3 module are not responsible of using the SQLite C API correctly.
• Don't overwrite BufferError with ValueError when conversion to BLOB fails.
• Raise ProgrammingError instead of Warning if user tries to execute() more
  than one SQL statement.
• Raise ProgrammingError instead of ValueError if an SQL query contains null characters.
• Make sure _pysqlite_set_result raises an exception if it returns -1.

Fixes #89022

[erlend-aasland]

@serhiy-storchaka would you mind reviewing this?

[erlend-aasland]

@serhiy-storchaka PTAL. I just fixed bug in _pysqlite_set_result that could result in a segfault.

[erlend-aasland]

@malemburg would you mind taking a look at this PR? I'm slowly trying to align the exceptions raised with PEP 249.

[JelleZijlstra]

Looks like you didn't push the changes I previously asked for.

[erlend-aasland]

Looks like you didn't push the changes I previously asked for.

Actually, it seems I forgot about this; I didn't make any changes yet :) I'll see if I can get to it any time soon. Thanks for the reminder!

[erlend-aasland]

I'd like to run this through the Django test suite before eventually merging. Also, I'll have a talk with MAL regarding this change.

[erlend-aasland]

I'd like to run this through the Django test suite before eventually merging. Also, I'll have a talk with MAL regarding this change.

I finally got to run this through the Django test suite, and it works all fine; one down, one to go.

Observations while running the Django test suite

I got sidetracked with a long bisect operation because I was using SQLite 3.39.0 (development version), and because b899126 produces a ton of warnings in the Django test suite. I reverted b899126 and compiled strictly against SQLite 3.36.0 (macOS bundled), and all was ok.

UPDATE: I had a chat the other day with @malemburg, to get his comments regarding three specific DB-API related changes in this PR. I take the liberty to quote him here (hope that's ok, Marc-Andre):

1. Raise InterfaceError iso. ProgrammingError for SQLITE_MISUSE. If SQLITE_MISUSE is raised, it is a sqlite3 module bug. Users of the sqlite3 module are not responsible of using the SQLite C API correctly.

   This sounds fine. InterfaceError is meant for module related errors.

2. Raise ProgrammingError iso.Warning if user tries to execute() more than one statement

   Yep, sounds fine.

3. Raise DataError iso. ValueError if query contains NULL characters

   Since queries are passed in by the programmer, I would use ProgrammingError here. DataError would be appropriate for errors related to e.g. wrong values passed in as bound parameters.

I will update the PR with the suggested change.