py/compile: Don't await __aiter__ special method in async-for. #3222
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MicroPython's original implementation of __aiter__ was correct for an earlier (provisional) version of PEP492 (CPython 3.5), where __aiter__ was an async-def function. But that changed in the final version of PEP492 (in CPython 3.5.2) where the function was changed to a normal one. See https://www.python.org/dev/peps/pep-0492/#why-aiter-does-not-return-an-awaitable See also the note at the end of this subsection in the docs: https://docs.python.org/3.5/reference/datamodel.html#asynchronous-iterators And for completeness the BPO: https://bugs.python.org/issue27243 To be consistent with the Python spec as it stands today (and now that PEP492 is final) this commit changes MicroPython's behaviour to match CPython: __aiter__ should return an async-iterable object, but is not itself awaitable. The relevant tests are updated to match. See adafruit#6267.
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Cherry-pick from @jonathanhogg:
MicroPython's original implementation of aiter was correct for an
earlier (provisional) version of PEP492 (CPython 3.5), where aiter was
an async-def function. But that changed in the final version of PEP492 (in
CPython 3.5.2) where the function was changed to a normal one. See
https://www.python.org/dev/peps/pep-0492/#why-aiter-does-not-return-an-awaitable
See also the note at the end of this subsection in the docs:
https://docs.python.org/3.5/reference/datamodel.html#asynchronous-iterators
And for completeness the BPO: https://bugs.python.org/issue27243
To be consistent with the Python spec as it stands today (and now that
PEP492 is final) this commit changes MicroPython's behaviour to match
CPython: aiter should return an async-iterable object, but is not
itself awaitable.
The relevant tests are updated to match.
See #6267.