gh-100160: Deprecate implicit creation of an event loop #100410
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Partially revert changes made in pythonGH-93453. asyncio.DefaultEventLoopPolicy.get_event_loop() now emits a DeprecationWarning and creates and sets a new event loop instead of raising a RuntimeError if there is no current event loop set.
serhiy-storchaka
requested review from
1st1,
asvetlov,
gvanrossum and
kumaraditya303
as code owners
Doc/library/asyncio-eventloop.rst
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| the result of calling ``get_event_loop_policy().get_event_loop()``. | ||
| the result of ``get_event_loop_policy().get_event_loop()`` call. |
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I liked the original phrasing better, or perhaps this:
the result of the
get_event_loop_policy().get_event_loop()call.
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One variant was in 3.12, other variant was in 3.12. I think @ambv edited it in one of PRs.
Applied your suggestion.
Doc/library/asyncio-eventloop.rst
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| the current loop was set. | ||
| .. deprecated:: 3.12 | ||
| Deprecation warning is emitted if there is no current event loop. | ||
| In future Python releases it will be an error. |
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Maybe
In some future Python release it will become an error.
| except AttributeError: | ||
| pass | ||
| else: | ||
| while f: |
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Can you add a comment explaining why this loop is needed? (IIUC it's so the warning is attached to a line outside asyncio itself?)
| break | ||
| f = f.f_back | ||
| stacklevel += 1 | ||
| import warnings |
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I see no reason to delay this import, since it's a toplevel import in base_events.py and proactor_events.py -- by the time this code runs those have been imported anyway.
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I prefer to only import warnings when it is used, so the code which does not use any deprecated feature will not need to import it. It also save us from forgetting to remove the import when warnings are replaced with errors. I think that we should do this in base_events.py and proactor_events.py.
| @@ -0,0 +1,3 @@ | |||
| Emit a deprecation warning in | |||
| :meth:`asyncio.DefaultEventLoopPolicy.get_event_loop` if there is no current | |||
| event loop set and a new event loop has been implicitly created. | |||
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(Same textual change as I suggested above.)
Co-authored-by: Guido van Rossum <gvanrossum@gmail.com>
…chaka/cpython into asyncio-get_event_loop3-3.12
Partially revert changes made in GH-93453.
asyncio.DefaultEventLoopPolicy.get_event_loop() now emits a DeprecationWarning and creates and sets a new event loop instead of raising a RuntimeError if there is no current event loop set.