[PATCH RFC] ui: add support for a tweakdefaults knob

[Yuya Nishihara]

On Wed, 14 Jun 2017 21:37:21 -0400, Augie Fackler wrote:
> # HG changeset patch
> # User Augie Fackler <augie at google.com>
> # Date 1497488194 14400
> #      Wed Jun 14 20:56:34 2017 -0400
> # Node ID 0e5ea7a86a8021d02218c35b07366ac6081ab3fb
> # Parent  3abba5bc34546951b11b1bd3f5e5c77b90d950d1
> ui: add support for a tweakdefaults knob

Queued this, thanks.

> @@ -241,8 +257,29 @@ class ui(object):
>                      u.fixconfig(section=section)
>              else:
>                  raise error.ProgrammingError('unknown rctype: %s' % t)
> +        u._maybetweakdefaults()
>          return u
>  
> +    def _maybetweakdefaults(self):
> +        if not self.configbool('ui', 'tweakdefaults'):
> +            return
> +        if self._tweaked or self.plain('tweakdefaults'):
> +            return

tweakdefaults can't be disabled by --config if it's enabled by rc files.
Maybe this could be fixed by moving ui._maybetweakdefaults() to dispatch.py
where color.setup() is called.

> +        # Note: it is SUPER IMPORTANT that you set self._tweaked to
> +        # True *before* any calls to setconfig(), otherwise you'll get
> +        # infinite recursion between setconfig and this method.
> +        #
> +        # TODO: We should extract an inner method in setconfig() to
> +        # avoid this weirdness.
> +        self._tweaked = True
> +        tmpcfg = config.config()
> +        tmpcfg.parse('<tweakdefaults>', tweakrc)
> +        for section in tmpcfg:
> +            for name, value in tmpcfg.items(section):
> +                if not self.hasconfig(section, name):
> +                    self.setconfig(section, name, value, "<tweakdefaults>")

I have no idea how we should process values which are only set in untrusted
config. Using hasconfig(untrusted=True) might be a bit safer, but there would
still be inconsistency.

Another problem is self._ocfg can shadow repo config which isn't loaded yet
when _maybetweakdefaults() is called.