[PATCH] py3: catch StopIteration from next() in generatorset

[Martin von Zweigbergk]

On Tue, Jun 20, 2017 at 2:53 PM, Sean Farley <sean at farley.io> wrote:
> Martin von Zweigbergk via Mercurial-devel
> <mercurial-devel at mercurial-scm.org> writes:
>
>> # HG changeset patch
>> # User Martin von Zweigbergk <martinvonz at google.com>
>> # Date 1497992441 25200
>> #      Tue Jun 20 14:00:41 2017 -0700
>> # Node ID f86d21c457209f5f5a139bcc808be33fbd930424
>> # Parent  0906385672d754f13a512fe70759f0463a069f1e
>> py3: catch StopIteration from next() in generatorset
>>
>> IIUC, letting the StopIteration through would not cause any bugs, but
>> not doing it makes the test-py3-commands.t pass.
>>
>> I have also diligently gone through all uses of next() in our code
>> base. They either:
>>
>>  * are not called from a generator
>>  * pass a default value to next()
>>  * catch StopException
>>  * work on infinite iterators
>>  * request a fixed number of items that matches the generated number
>>  * are about batching in wireproto which I didn't quite follow
>>
>> I'd appreciate if Augie or someone else could take a look at the
>> wireproto batching and convince themselves that the next(batchable)
>> calls there will not raise a StopIteration.
>
> I was just thinking of doing something like this. Shouldn't we just
> 'return None' in Mercurial instead of 'raise StopIteration'?

I thought "return" was just short for "return None". Are you just
saying that we prefer "return None" in Mercurial? Should I send a v2?