Latest release breaks hypothesis tests in CPython main branch

[skirpichev]

See python/cpython#122686. Pinning to "attrs<=23.2.0" - a workaround.

[hynek]

I’m afk, can I have a
Short, Self Contained, Correct, Example please?

[skirpichev]

Sorry, I didn't deep debugging (yet). If that helps, tracebacks from above job looks like:

[...]
  File "/home/runner/work/cpython/cpython-builddir/hypovenv/lib/python3.14/site-packages/hypothesis/internal/conjecture/data.py", line 2466, in stop_example
    self.tags.update([structural_coverage(l) for l in labels_for_structure])
                      ~~~~~~~~~~~~~~~~~~~^^^
  File "/home/runner/work/cpython/cpython-builddir/hypovenv/lib/python3.14/site-packages/hypothesis/internal/conjecture/data.py", line 170, in structural_coverage
    return STRUCTURAL_COVERAGE_CACHE.setdefault(label, StructuralCoverageTag(label))
                                                       ~~~~~~~~~~~~~~~~~~~~~^^^^^^^
TypeError: StructuralCoverageTag.__init__() takes 1 positional argument but 2 were given

It's this class in Hypothesis:
https://github.com/HypothesisWorks/hypothesis/blob/3c15b34ece30825ed153a0b350f5847efb30dd79/hypothesis-python/src/hypothesis/internal/conjecture/data.py#L157-L160

Maybe hypothesis package should add pinning, but it's not clear for me from release notes that was broken here.

[hynek]

From looking on my phone it looks like the breakage is that we now use the official dataclass transform decorator and they’re applying is a second time. I think that’s something they have to fix, this is just the price of the typing bleeding edge. Has someone opened a ticket over there?

[skirpichev]

HypothesisWorks/hypothesis#4067

[hynek]

So it looks like attrs can't find annotation-only fields Python 3.14 only anymore.

It's caused by 689a0e6 and my wild guess is that it's related to PEP 649 / PEP 749.