Some subjective feedback from my Windows machine with VS 2022:

• To get the tests compiling, I needed to replace the target framework identifiers fromnet6.0 tonet8.0 in the .csproj files (that's maybe a subset ofUse .NET 8.0 and uv in CI #2612).
• You forgot to reapply thealignment hack from TypeOffset313.cs. With that applied, I get a few access memory violations less.

Also had to replace the target framework from net6.0 to net8.0. Also some feedback for .net 8:

• Add#pragma warning disable SYSLIB0011 for where BinaryFormatter is being used
• Add<EnableUnsafeBinaryFormatterSerialization>true</EnableUnsafeBinaryFormatterSerialization> to all projects
• Remove NonCopyable from ref struct NewReference
• Remove NonCopyable from ref struct StolenReference
• Need to consider migrating away from using BinaryFormatter as it will be deprecated in .net9

And now getting an access memory violation for PyGC_Collect(); in Runtime.cs

Status report: After applying the alignment "fix" (thanks!), things work for the most part. There are some crashes in explicit garbage collection, so I have disabled those tests for now.

Also, we currently apparently have a weird inheritance order for our meta type, which leads to it using thePyObject_GenericSetAttr instead oftype_setattro, which in turn triggers assertions sincepython/cpython@5a1618a

@filmor As the CI seems to be pretty broken (pytest: command not found), could you please provide a list of the outstanding tasks for this PR to reach completion, as you did in the description block ofthe corresponding 3.13 PR.

Things not clear to me:

• do you want to have the exluded tests re-enabled?
• do the tests failing due to missing BinarySerializer functionality block this PR?

Thanks ;-)

There you go. There are still pending issues with the embedding tests that are being worked on in#2638, but I'd be fine with releasing a wheel if we get to the point that all Python tests run through without crashes on 3.14.

This is the issue that we run into with thePyObject_GenericSetAttr usage:

• [BUG] Cython uses PyObject_GenericSetAttr() on types in Limited API cython/cython#6323
• Related Python PR:gh-118362: Fix thread safety around lookups from the type cache in the face of concurrent mutators python/cpython#118454

@lostmsu Please have a look. It will require quite a bit more work to get everything green again (CI-wise, in particular around the embedding), but with these changes, we should be able to release a wheel for Python 3.14.