> On Sep 16, 2016, at 09:48, Pierre-Yves David <pierre-yves.da...@ens-lyon.org>
> wrote:
>
>
>
> On 09/14/2016 05:11 AM, Augie Fackler wrote:
>> # HG changeset patch
>> # User Augie Fackler <au...@google.com>
>> # Date 1472584421 14400
>> # Tue Aug 30 15:13:41 2016 -0400
>> # Node ID 828f260114a3a55e246cb5de434e75bdc782e4ad
>> # Parent 600be3c9acee0ec14bd19c032cc0480e4501fe8c
>> fancyopts: disallow true as a boolean flag default (API)
>>
>> This was nonsense, as there's not been a way for the user to
>> un-specify the flag. Restricting this behavior will open the door to
>> some nice fit-and-finish functionality in a later patch, and shouldn't
>> break any third party extensions. This is marked as (API) since it
>> might break a third party extension, but given the fact that it was
>> silly before that's mostly a formality.
>
> I really wish we had details on this as requested in the review of the
> previous version. Especially because I remember that forbidding 'True' as
> default was making other improvement hard so I'm not sure why we have to do
> this.
Err? I'm not sure what you're asking for now, and I definitely didn't
understand it on the last go round.
>> Due to how early parsing of global options works, we have to add some
>> extra coupling between fancyopts and dispatch so that we can provide a
>> "default" of True for already-parsed boolean flags when doing
>> command-level flag parsing.
>>
>> diff --git a/mercurial/dispatch.py b/mercurial/dispatch.py
>> --- a/mercurial/dispatch.py
>> +++ b/mercurial/dispatch.py
>> @@ -555,7 +555,10 @@ def _parse(ui, args):
>>
>> # combine global options into local
>> for o in commands.globalopts:
>> - c.append((o[0], o[1], options[o[1]], o[3]))
>> + # Passing a tuple of length six through into the option parser
>> + # allows otherwise-illegal defaults to survive, which is how
>> + # we handle global options like --quiet.
>> + c.append((o[0], o[1], options[o[1]], o[3], '', True))
>>
>> try:
>> args = fancyopts.fancyopts(args, c, cmdoptions, gnu=True)
>> diff --git a/mercurial/fancyopts.py b/mercurial/fancyopts.py
>> --- a/mercurial/fancyopts.py
>> +++ b/mercurial/fancyopts.py
>> @@ -79,10 +79,22 @@ def fancyopts(args, options, state, gnu=
>> alllong = set(o[1] for o in options)
>>
>> for option in options:
>> - if len(option) == 5:
>> + boolok = False
>> + if len(option) == 6:
>> + # If the tuple is of length 6, then it's a global option
>> + # that was already parsed, so we're really just passing
>> + # its "default" through the second phase of flags parsing
>> + # (for command-level flags). As a result, we have to allow
>> + # defaults of True and not rewrite defaults of False.
>> + short, name, default, comment, dummy, dummy = option
>> + boolok = True
>> + elif len(option) == 5:
>> short, name, default, comment, dummy = option
>> else:
>> short, name, default, comment = option
>> + if default is True and not boolok:
>> + raise ValueError('fancyopts does not support default-true '
>> + 'boolean flags: %r' % name)
>
> As pointed in a previous review, identity testing to boolean really raise red
> flag here. I see this as a significant sign of a bad idea and something we
> should avoid at all cost.
Calm down - this isn't the one that was pointed out in the past, and I didn't
notice this one as I was doing reworks for v3. I don't disagree with your
opinion here.
It sounds like you should be mailing a check-code rule about 'is (True|False)'
to forbid this pattern.
> I see you have a longer reply about handling of the tri-state later in this
> thread, I'll reply with more details there.
>
> Cheers,
>
> --
> Pierre-Yves David
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