Description

JelleZijlstra

opened on May 10, 2023

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Code sample:

def outer(x):
    return [lambda: x for x in range(x)]

print([f() for f in outer(2)])

On 3.11, this produces [1, 1] as expected.

But on current main, I get:

>>> [f() for f in outer(2)]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 2, in outer
TypeError: 'cell' object cannot be interpreted as an integer

Almost certainly due to PEP 709 / #101441, cc @carljm.

Linked PRs

• gh-104357: fix inlined comprehensions that close over iteration var #104368

Reacted by sunmy2019 and Carl Meyer

Activity

1. JelleZijlstra

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   release-blocker

   on May 10, 2023
2. ezio-melotti

   added this to Release and Deferred blockers 🚫on May 10, 2023
3. github-project-automation

   moved this to Todo in Release and Deferred blockers 🚫on May 10, 2023
4. carljm

   self-assigned this

   on May 10, 2023
5. carljm commented on May 10, 2023

   

   carljm

   on May 10, 2023

   Member

   More actions

   Thanks for finding this case! I had tests for similar cases with lambda inside the comprehension using the same name as non-cell outside the comprehension, but they were all of the form:

   def outer():
       x = 2
       return [lambda: x for x in range(x)]
   

   The key factor in your example is that there is no store to x in the outer scope, because it is an argument.
6. carljm

   added a commit that references this issue on May 10, 2023

   pythongh-104357: fix inlined comprehensions with cells

   a9c5a4f
7. JelleZijlstra

   closed this as completedin #104368on May 11, 2023
8. github-project-automation

   moved this from Todo to Done in Release and Deferred blockers 🚫on May 11, 2023
9. JelleZijlstra

   added a commit that references this issue on May 11, 2023

   gh-104357: fix inlined comprehensions that close over iteration var (#…

   fcd5fb4
10. carljm

    added 2 commits that reference this issue on May 11, 2023

    Merge branch 'main' into supermon

    19b3d9e

    Merge branch 'main' into fixloadsuperspec

    4456dd6

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