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| author | Jonathan Hogg <me@jonathanhogg.com> | 2020-07-21 18:47:28 +0100 |
|---|---|---|
| committer | Kenny <3454741+WarriorOfWire@users.noreply.github.com> | 2020-07-24 22:55:37 -0700 |
| commit | 901f3dce6e5e7c1501550ca0b7f3283848194a2e (patch) | |
| tree | c2a1b03cd7f6b77dc6e4fad9e7297c9ab16c2796 | |
| parent | a6e048686fe6999c4231582b7d9e69a7dc679257 (diff) | |
py/compile: Don't await __aiter__ special method in async-for.
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.
| -rw-r--r-- | py/compile.c | 3 | ||||
| -rw-r--r-- | tests/basics/async_for.py | 2 | ||||
| -rw-r--r-- | tests/basics/async_for2.py | 5 | ||||
| -rw-r--r-- | tests/basics/async_for2.py.exp | 4 |
4 files changed, 5 insertions, 9 deletions
diff --git a/py/compile.c b/py/compile.c index 9b0d29998..58b1813c7 100644 --- a/py/compile.c +++ b/py/compile.c @@ -1741,7 +1741,8 @@ STATIC void compile_async_for_stmt(compiler_t *comp, mp_parse_node_struct_t *pns uint try_finally_label = comp_next_label(comp); compile_node(comp, pns->nodes[1]); // iterator - compile_await_object_method(comp, MP_QSTR___aiter__); + EMIT_ARG(load_method, MP_QSTR___aiter__, false); + EMIT_ARG(call_method, 0, 0, 0); compile_store_id(comp, context); START_BREAK_CONTINUE_BLOCK diff --git a/tests/basics/async_for.py b/tests/basics/async_for.py index 6b4e136d5..5fd054082 100644 --- a/tests/basics/async_for.py +++ b/tests/basics/async_for.py @@ -6,7 +6,7 @@ class AsyncIteratorWrapper: print('init') self._it = iter(obj) - async def __aiter__(self): + def __aiter__(self): print('aiter') return self diff --git a/tests/basics/async_for2.py b/tests/basics/async_for2.py index 025ff9c4d..add74dd38 100644 --- a/tests/basics/async_for2.py +++ b/tests/basics/async_for2.py @@ -1,4 +1,4 @@ -# test waiting within "async for" aiter/anext functions +# test waiting within "async for" __anext__ function import sys if sys.implementation.name in ('micropython', 'circuitpython'): @@ -21,9 +21,8 @@ class ARange: self.cur = 0 self.high = high - async def __aiter__(self): + def __aiter__(self): print('aiter') - print('f returned:', await f(10)) return self async def __anext__(self): diff --git a/tests/basics/async_for2.py.exp b/tests/basics/async_for2.py.exp index 886232f7b..52bbe90c8 100644 --- a/tests/basics/async_for2.py.exp +++ b/tests/basics/async_for2.py.exp @@ -1,9 +1,5 @@ init aiter -f start: 10 -coro yielded: 11 -coro yielded: 12 -f returned: 13 anext f start: 20 coro yielded: 21 |