[Python-ideas] Revised**12 PEP on Yield-From
erik at cq2.org
Wed Apr 22 18:05:11 CEST 2009
2009/4/22 Jacob Holm <jh at improva.dk>:
> In other words, the ValueError in the following example is swallowed by close():
>>>> def foo():
> ... yield 'bar'
> ... raise ValueError('baz')
>>>> g = foo()
I have the same code here, it does not raise an exception indeed.
> This looks like close() doesn't actually behave as it should according to PEP342. Interesting...
>From PEP342 (Thanks Jacob, for the reference):
4. Add a close() method for generator-iterators, which raises
GeneratorExit at the point where the generator was paused. If
the generator then raises StopIteration (by exiting normally, or
due to already being closed) or GeneratorExit (by not catching
the exception), close() returns to its caller. If the generator
yields a value, a RuntimeError is raised. If the generator
raises any other exception, it is propagated to the caller.
close() does nothing if the generator has already exited due to
an exception or normal exit.
> I would call that a bug.
I agree with that.
> I can't believe that none of us actually tested that...
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