Name lookup in annotation scopes in classes does not work with non-dict globals

[JelleZijlstra]

Bug report

Bug description:

This works:

class customdict(dict):
    def __missing__(self, key):
        return key

code = compile("type Alias = undefined", "test", "exec")
ns = customdict()
exec(code, ns)
Alias = ns["Alias"]
assert Alias.__value__ == "undefined"

But this does not:

code = compile("class A: type Alias = undefined", "test", "exec")
ns = customdict()
exec(code, ns)
Alias = ns["A"].Alias
assert Alias.__value__ == "undefined"

This is a problem for PEP 649 because we're going to rely on a non-dict globals namespace.

CPython versions tested on:

CPython main branch

Operating systems tested on:

macOS

Linked PRs

• gh-119821: Support non-dict globals in LOAD_FROM_DICT_OR_GLOBALS #119822
• [3.13] gh-119821: Support non-dict globals in LOAD_FROM_DICT_OR_GLOBALS (#119822) #119889
• [3.12] gh-119821: Support non-dict globals in LOAD_FROM_DICT_OR_GLOBALS (#119822) #119890
• [3.12] gh-119821: Fix refleak in LOAD_FROM_DICT_OR_GLOBALS #119975

[encukou]

3.12 refleak buildbots started failing when the backport was merged.

$ ./python -m test test_type_params -R:
Using random seed: 3855735070
0:00:00 load avg: 0.70 Run 1 test sequentially
0:00:00 load avg: 0.70 [1/1] test_type_params
beginning 9 repetitions. Showing number of leaks (. for 0 or less, X for 10 or more)
12345:6789
XXXXX XXXX
test_type_params leaked [12, 12, 12, 12] references, sum=48
test_type_params leaked [8, 8, 8, 8] memory blocks, sum=32
test_type_params failed (reference leak)

== Tests result: FAILURE ==

1 test failed:
    test_type_params

Total duration: 326 ms
Total tests: run=83
Total test files: run=1/1 failed=1
Result: FAILURE

[JelleZijlstra]

Thanks @encukou for noticing the refleak! This has been fixed now.