bpo-42064: Add module backref to sqlite3 callback context

[erlend-aasland]

Make sure that the module state will always outlive the callback context
by holding a strong reference to the module object in the callback
context.

https://bugs.python.org/issue42064

[erlend-aasland]

FYI, first attempt is in a2d3eae

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @erlend-aasland for commit 9150dfc 🤖

If you want to schedule another build, you need to add the ":hammer: test-with-buildbots" label again.

[erlend-aasland]

The AMD64 Arch Linux Asan Debug PR buildbot failure is unrelated to this PR.

[erlend-aasland]

FYI, the windows and asan CI failures are unrelated.

[encukou]

Whoa, that's certainly a big PR.
Did you consider adding a module pointer to pysqlite_state instead, and increfing/decrefing that? You don't need to store the pointer in the actual struct that "owns" the reference.

[erlend-aasland]

Whoa, that's certainly a big PR.

Did you filter out the auto-generated clinic changes? (You can use the viewed checkbox in GitHub's Files changed PR tab.)

$ git diff main  --stat Modules/_sqlite/*.[ch]
 Modules/_sqlite/connection.c | 55 ++++++++++++++++++++++++++++++++++++++-----------------
 Modules/_sqlite/connection.h |  1 +
 2 files changed, 39 insertions(+), 17 deletions(-)

[encukou]

This looks good, thanks!
One nitpick: it might not be not immediately clear that create_callback_context needs the defining class (i.e. exactly the Connection class, not a subclass which could have a different module). Do you want to add a comment on that?

[erlend-aasland]

This looks good, thanks!

Thanks for reviewing :)

One nitpick: it might not be not immediately clear that create_callback_context needs the defining class (i.e. exactly the Connection class, not a subclass which could have a different module). Do you want to add a comment on that?

Yes, that's a good idea.

[erlend-aasland]

PTAL

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 Arch Linux Asan Debug 3.x has failed when building commit 09c04e7.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/all/#builders/585/builds/655) and take a look at the build logs.
4. Check if the failure is related to this commit (09c04e7) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/all/#builders/585/builds/655

Summary of the results of the build (if available):

Click to see traceback logs

remote: Enumerating objects: 8, done.        
remote: Counting objects:  12% (1/8)        
remote: Counting objects:  25% (2/8)        
remote: Counting objects:  37% (3/8)        
remote: Counting objects:  50% (4/8)        
remote: Counting objects:  62% (5/8)        
remote: Counting objects:  75% (6/8)        
remote: Counting objects:  87% (7/8)        
remote: Counting objects: 100% (8/8)        
remote: Counting objects: 100% (8/8), done.        
remote: Compressing objects:  12% (1/8)        
remote: Compressing objects:  25% (2/8)        
remote: Compressing objects:  37% (3/8)        
remote: Compressing objects:  50% (4/8)        
remote: Compressing objects:  62% (5/8)        
remote: Compressing objects:  75% (6/8)        
remote: Compressing objects:  87% (7/8)        
remote: Compressing objects: 100% (8/8)        
remote: Compressing objects: 100% (8/8), done.        
remote: Total 8 (delta 0), reused 1 (delta 0), pack-reused 0        
From https://github.com/python/cpython
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HEAD is now at 09c04e7f0d [bpo-42064](https://bugs.python.org/issue42064): Add module backref to `sqlite3` callback context (GH-28242)
Switched to and reset branch 'main'

renaming build/scripts-3.11/pydoc3 to build/scripts-3.11/pydoc3.11
renaming build/scripts-3.11/idle3 to build/scripts-3.11/idle3.11
renaming build/scripts-3.11/2to3 to build/scripts-3.11/2to3-3.11

renaming build/scripts-3.11/pydoc3 to build/scripts-3.11/pydoc3.11
renaming build/scripts-3.11/idle3 to build/scripts-3.11/idle3.11
renaming build/scripts-3.11/2to3 to build/scripts-3.11/2to3-3.11

renaming build/scripts-3.11/pydoc3 to build/scripts-3.11/pydoc3.11
renaming build/scripts-3.11/idle3 to build/scripts-3.11/idle3.11
renaming build/scripts-3.11/2to3 to build/scripts-3.11/2to3-3.11
make: *** [Makefile:1352: buildbottest] Terminated

Cannot open file '/buildbot/buildarea/3.x.pablogsal-arch-x86_64.asan_debug/build/test-results.xml' for upload