gh-108518: Make concurrent.futures.Executor.map() consistent with built-in map() #109497
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Lib/concurrent/futures/_base.py
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| @@ -566,6 +568,46 @@ def set_exception(self, exception): | |||
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| __class_getitem__ = classmethod(types.GenericAlias) | |||
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| class _FutureResult(object): | |||
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It looks over-engineered. Why not simply use a result-exception tuple?
Lib/concurrent/futures/_base.py
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| @classmethod | ||
| def from_generator(cls, gen): | ||
| return cls(gen) |
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It is redundant. You can simply use constructor.
Lib/concurrent/futures/_base.py
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| @@ -648,6 +695,25 @@ def __exit__(self, exc_type, exc_val, exc_tb): | |||
| return False | |||
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| class _MapResultIterator(object): | |||
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(object) is redundant.
Current iterator has the close() method, calling which cancels all futures. It is a useful feature. Please add a close() method in a new class. I do not think that it is worth to implement send() and throw(), they are not so useful and are rather an implementation detail.
| ) as gen: | ||
| with self.assertRaises(TimeoutError): | ||
| next(gen) | ||
| iterator = pool.map(log_n_wait, ["second"], timeout=0) |
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This code should continue to work without changes.
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I resolved conflicts, fixed some errors, simplified code, added the close method, added docs and more tests. TimeoutError immediately cancels all calls.
Now this PR LGTM.
@pitrou, @brianquinlan, @vstinner, @gpshead, could anybody of your please take a look at this if you have a time?
The current behavior of
concurrent.futures.Executor.map()is not consistent with documentation:When a
nextcall raises an Exception, you can not get any subsequent Future result, even if the computation has completed and returns a valid result.If it is expected or don't consider to make changes to this behavior, I'd like to make a PR to update the relevant docs.