python
feat: new mypyc primitive for weakref.ref
This PR adds a new mypyc primitive for weakref.ref
I wasn't able to figure out what name mypyc expects for weakref.proxy, so I took that out and will keep that for a separate PR later on. ref is more commonly used than proxy anyway.
for later, I tried:
- weakref.proxy
- weakref.ProxyType
- weakref.weakproxy
no luck with those
also for later, I'll need to finish #19145 to add a primitive for weakref.ref.__call__
@JukkaL I've cleaned up the commit history and this is now ready for review.
Oh great, I was trying and trying different ways to do this and eventually gave up. Will put that together sometime this week.
Any thoughts on how I might determine the correct fullname for weakref.proxy so I can handle that with both cases (1- and 2-arg) at the same time?
On Mon, Jun 2, 2025 at 12:12 PM Jukka Lehtosalo @.***> wrote:
@.**** commented on this pull request.
Thanks for the PR! Left a suggestion about how to make this more general.
In mypyc/primitives/weakref_ops.py https://github.com/python/mypy/pull/19099#discussion_r2121608094:
@@ -0,0 +1,13 @@ +from mypyc.ir.ops import ERR_MAGIC +from mypyc.ir.rtypes import object_rprimitive +from mypyc.primitives.registry import function_op
+# Weakref operations + +new_ref_op = function_op(
- name="weakref.ReferenceType",
- arg_types=[object_rprimitive, object_rprimitive],
- return_type=object_rprimitive,
- c_function_name="PyWeakref_NewRef",
Can you also support calls with a single argument, since this is probably quite common?
You'd need to add another function_op with arg_types=[object_rprimitive], and probably something like extra_int_constants=[(0, pointer_rprimitive)], to add an implicit NULL argument.
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@JukkaL I know I said I'd do it later this week, but I've already finished. This is ready for review.
Any thoughts on how I might determine the correct fullname for weakref.proxy so I can handle that with both cases (1- and 2-arg) at the same time?
You can look at how it's defined in mypy/typeshed/stdlib/weakref.pyi. You can also print the fullname of the relevant mypy AST node e.g. in some visitor (visit_member_expr).
hmm. It shows ProxyType in the typeshed though that wasn't working for me before. Let me try this again
It didn't work. I'll keep working on proxy in #19217 , this one is ready to merge if you agree
I got it to work for weakref.proxy on #19217. The C code generates correctly but I believe I've exposed a bug in mypyc's reference counting as my new pytest cases fail both with the new code and with the original builtin. The weakly-proxied object is being destroyed too early, while there should still be a strong reference to it.
@JukkaL Any other changes you want to see to this one before merging? Thanks for your assistance helping me figure out the above.
uh-oh, the tests started to fail after I merged in recent changes to master. Looks like there was a regression of some sort.
According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅
![github-actions[bot] avatar](https://avatars.githubusercontent.com/in/15368?v=4 "Published by a pub.dev verified publisher"){kind=small}
According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅
According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅
Great, I got it working! Merging this will resolve https://github.com/mypyc/mypyc/issues/1116
@ilevkivskyi Could I trouble you for a review on this one as well? My other weakref PRs build on top of this and would be much easier to finish up / review once this one is merged in