[PATCH 04 of 10 RFC v2] compat: module to handle different ui.compat settings

[Jun Wu]

Excerpts from David Soria Parra's message of 2017-03-12 15:40:27 -0700:

[...]

> +# compat.py - handlign compatibility settings

spell: "handling"

> +#
> +# Copyright 2005-2017 Mercurial Steering Committee
> +#
> +# This software may be used and distributed according to the terms of the
> +# GNU General Public License version 2 or any later version.
> +from __future__ import absolute_import
> +
> +import collections
> +from . import (
> +    util,
> +)
> +
> +# The initialization msut be done with a list and not a dict, as a list

spell: "must"

> +# is sorted while a dictionary is not.
> +COMPAT = util.sortdict([
> +    ('compat', {}),
> +    ('latest', {})],
> +)

The format looks a bit inconsistent, maybe:

      ('latest', {}),
  ]),

> +
> +def modernize(ui):
> +    compats = compatlevel(ui)
> +    for section, d in compats.items():
> +        for key, value in d.items():
> +            ui._cfg['defaults'].set(section, key, value)

Maybe set source, so "hg config --debug" shows where the configs come from.

> +
> +def compatlevel(ui):
> +    if ui.plain('compat'):
> +        requested = 'compat'
> +    else:
> +        requested = ui.config('ui', 'compat', 'compat')
> +
> +    result = {}
> +    for level, configs in COMPAT.items():
> +        result.update(configs)
> +        if level == requested:
> +            # defaults is sorted. We can abort once we reached
> +            # the requested level.
> +            break
> +    return result