PEP 479 says “Python 3.6: Non-silent deprecation warning” if “StopIteration bubbles out of a generator not under __future__ import”. Currently I see a PendingDeprecationWarning in this case; I guess this should be changed to DeprecationWarning in the 3.6 branch.

I have submitted a patch. I have replace `PyExc_PendingDeprecationWarning` to `PyExc_DeprecationWarning` in Objects/genobject.c

Can anyone please review?

Have you tried running the test suite? I suspect there are tests that will fail. E.g. the tests in revision 2771a0ac806b would need to be changed over to DeprecationWarning as well.

Yes @martin.panter, the tests were failing. But, I didn't know where the tests for PendingDeprecationWarning were added. Thanks for telling the changeset. I have updated the patch. Can you please have a look?

FYI I found that changeset by doing annotate on the file that you originally changed <https://hg.python.org/cpython/annotate/default/Objects/genobject.c#l181>, which is an index of the changesets that last modified each line.

Thanks for the patch, I think it is generally good. Perhaps this also needs a short notice in What’s New, a bit like <https://docs.python.org/3/whatsnew/3.5.html#deprecated-python-behavior>?

Thanks @martin.panter. I learnt something new, I didn't know about annotate before.
I have updated the patch.
Thanks again.

@martin.panter Any reviews for the patch? Is it ready to merge?

Thanks for the updated patch. There are a couple minor problems with the What’s New entry, which you can fix if you want, or I could fix if I get around to merging it:

* Bullet point should probably be wrapped onto multiple lines
* According to the 3.5 What’s New, the DeprecationWarning is “non-silent”, but I would just drop the “silent” attribute (Once upon a time in Python 2, DeprecationWarning was apparently enabled by default, in constrast with PendingDeprecationWarning, which was silenced by default.)
* Change “which will trigger a RuntimeError” → “and will trigger . . .”
* Missing full stop at the end

@martin.panter I have fixed the What's New docs. I have updated the patch. Thanks!

New changeset 73f89182bb4d by Martin Panter in branch 'default':
Issue #26136: Upgrade the generator_stop warning to DeprecationWarning
https://hg.python.org/cpython/rev/73f89182bb4d

Thanks for your work Anish