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Calling super().__init__ in subclasses of typing.Protocol raises RecursionError #89284

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hauntsaninja opened this issue Sep 6, 2021 · 11 comments
Closed

Calling super().__init__ in subclasses of typing.Protocol raises RecursionError #89284

hauntsaninja opened this issue Sep 6, 2021 · 11 comments
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3.9 only security fixes 3.10 only security fixes 3.11 only security fixes release-blocker stdlib Python modules in the Lib dir

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@hauntsaninja
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BPO 45121
Nosy @ericvsmith, @ambv, @JelleZijlstra, @pablogsal, @miss-islington, @hauntsaninja, @uriyyo, @Fidget-Spinner
PRs
  • bpo-45121: Fix issue when Protocol.__init__ raise RecursionError #28206
  • [3.10] bpo-45121: Fix RecursionError when calling Protocol.__init__ from a subclass' __init__ (GH-28206) #28232
  • [3.9] bpo-45121: Fix RecursionError when calling Protocol.__init__ from a subclass' __init__ (GH-28206) #28233
    		•

    Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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    GitHub fields:

    assignee = None
closed_at = <Date 2021-09-19.19:19:02.151>
created_at = <Date 2021-09-06.22:05:20.335>
labels = ['release-blocker', 'library', '3.9', '3.10', '3.11']
title = 'Calling super().__init__ in subclasses of typing.Protocol raises RecursionError'
updated_at = <Date 2021-10-04.19:18:42.785>
user = 'https://github.com/hauntsaninja'

    bugs.python.org fields:

    activity = <Date 2021-10-04.19:18:42.785>
actor = 'pablogsal'
assignee = 'none'
closed = True
closed_date = <Date 2021-09-19.19:19:02.151>
closer = 'pablogsal'
components = ['Library (Lib)']
creation = <Date 2021-09-06.22:05:20.335>
creator = 'hauntsaninja'
dependencies = []
files = []
hgrepos = []
issue_num = 45121
keywords = ['patch']
message_count = 11.0
messages = ['401184', '401197', '401199', '401200', '401284', '401369', '401384', '401385', '401386', '402164', '403161']
nosy_count = 8.0
nosy_names = ['eric.smith', 'lukasz.langa', 'JelleZijlstra', 'pablogsal', 'miss-islington', 'hauntsaninja', 'uriyyo', 'kj']
pr_nums = ['28206', '28232', '28233']
priority = 'release blocker'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue45121'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']
    @hauntsaninja
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    Consider:

    from typing import Protocol

class P(Protocol):
    ...

class C(P):
    def __init__(self):
        super().__init__()

C()

    This code passes without error on 3.9.6.

    With 3.9.7, we get:

    Traceback (most recent call last):
  File "/Users/shantanu/dev/test.py", line 10, in <module>
    C()
  File "/Users/shantanu/dev/test.py", line 8, in __init__
    super().__init__()
  File "/Users/shantanu/.pyenv/versions/3.9.7/lib/python3.9/typing.py", line 1083, in _no_init
    raise TypeError('Protocols cannot be instantiated')
TypeError: Protocols cannot be instantiated

    I bisected this to:

    bpo-44806: Fix __init__ in subclasses of protocols (GH-27545) (GH-27559)

    Note there is also an interaction with the later commit:

    bpo-45081: Fix __init__ method generation when inheriting from Protocol (GH-28121) (GH-28132)

    This later commit actually causes a RecursionError:

      File "/Users/shantanu/dev/cpython/Lib/typing.py", line 1103, in _no_init_or_replace_init
    cls.__init__(self, *args, **kwargs)
  File "/Users/shantanu/dev/test.py", line 8, in __init__
    super().__init__()
  File "/Users/shantanu/dev/cpython/Lib/typing.py", line 1103, in _no_init_or_replace_init
    cls.__init__(self, *args, **kwargs)
  File "/Users/shantanu/dev/test.py", line 8, in __init__
    super().__init__()

    Originally reported by @tyralla on Gitter.

    @hauntsaninja hauntsaninja added 3.9 only security fixes stdlib Python modules in the Lib dir labels Sep 6, 2021
    @ericvsmith
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    Possibly related to bpo-45081, which ended up not having anything to do with dataclasses (despite the title).

    Can you check if that fix solves your problem?

    @hauntsaninja
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    As I mentioned in the post, bpo-45081 actually makes this issue worse, since we get a RecursionError.

    I think TypeError: Protocols cannot be instantiated is probably okay behaviour (as opposed to RecursionError), more just unfortunate that it seems to be an unanticipated breaking change.

    @hauntsaninja
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    Sorry if my message was confusing. Hopefully the following makes things clear:

    3.9.6: snippet runs without error

    3.9.7, with bpo-44806: (a probably reasonable) TypeError, but a breaking change

    main, with bpo-45081: RecursionError

    @ericvsmith
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    Sorry I didn't notice your reference to bpo-45081.

    @Fidget-Spinner Fidget-Spinner added 3.10 only security fixes 3.11 only security fixes labels Sep 7, 2021
    @Fidget-Spinner Fidget-Spinner changed the title Regression in 3.9.7 with typing.Protocol Calling super().__init__ in subclasses of typing.Protocol raises RecursionError Sep 7, 2021
    @Fidget-Spinner Fidget-Spinner added 3.10 only security fixes 3.11 only security fixes labels Sep 7, 2021
    @Fidget-Spinner Fidget-Spinner changed the title Regression in 3.9.7 with typing.Protocol Calling super().__init__ in subclasses of typing.Protocol raises RecursionError Sep 7, 2021
    @Fidget-Spinner
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    New changeset c11956a by Yurii Karabas in branch 'main':
    bpo-45121: Fix RecursionError when calling Protocol.__init__ from a subclass' __init__ (GH-28206)
    c11956a

    @ambv
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    ambv commented Sep 8, 2021

    New changeset 99506dc by Ken Jin in branch '3.9':
    [3.9] bpo-45121: Fix RecursionError when calling Protocol.__init__ from a subclass' __init__ (GH-28206) (GH-28233)
    99506dc

    @ambv
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    ambv commented Sep 8, 2021

    New changeset c081649 by Miss Islington (bot) in branch '3.10':
    bpo-45121: Fix RecursionError when calling Protocol.__init__ from a subclass' __init__ (GH-28206) (GH-28232)
    c081649

    @ambv
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    ambv commented Sep 8, 2021

    Pablo, marking as release blocker. PR #72419 is merged to 3.10. It should be cherry-picked for 3.10.0 inclusion.

    @pablogsal
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    Pablo, marking as release blocker. PR #72419 is merged to 3.10. It should be cherry-picked for 3.10.0 inclusion.

    Done!

    @pablogsal
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    New changeset db762a9 by Pablo Galindo (Miss Islington (bot)) in branch '3.10':
    bpo-45121: Fix RecursionError when calling Protocol.__init__ from a subclass' __init__ (GH-28206) (GH-28232)
    db762a9

    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
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