[PATCH 07 of 10 V5] rcutil: let environ override system configs (BC)

[Ryan McElroy]

On 3/27/17 7:02 AM, Jun Wu wrote:
> # HG changeset patch
> # User Jun Wu <quark at fb.com>
> # Date 1490589217 25200
> #      Sun Mar 26 21:33:37 2017 -0700
> # Node ID 38572bb2cffd815526a727bc6f3aacdca2902f4f
> # Parent  9b0aa30bf151b6c0e999b017fd328e29440bd447
> rcutil: let environ override system configs (BC)

Small nits inline. Could easily be addressed by a follow-up.

>
> This is BC because system configs won't be able to override $EDITOR, $PAGER.
> The new behavior is arguably more rational.
>
> diff --git a/mercurial/commands.py b/mercurial/commands.py
> --- a/mercurial/commands.py
> +++ b/mercurial/commands.py
> @@ -1807,4 +1807,6 @@ def config(ui, repo, *values, **opts):
>           if t == 'path':
>               ui.debug('read config from: %s\n' % f)
> +        elif t == 'items':
> +            pass
>           else:
>               raise error.ProgrammingError('unknown rctype: %s' % t)
> diff --git a/mercurial/rcutil.py b/mercurial/rcutil.py
> --- a/mercurial/rcutil.py
> +++ b/mercurial/rcutil.py
> @@ -77,8 +77,12 @@ def rccomponents():
>       name, value, source) that should fill the config directly.
>       '''
> +    envrc = ('items', envrcitems())
> +
>       global _rccomponents
>       if _rccomponents is None:
>           if 'HGRCPATH' in encoding.environ:
> -            _rccomponents = []
> +            # assume HGRCPATH is all about user configs so environments can be
> +            # overridden.
> +            _rccomponents = [envrc]
>               for p in encoding.environ['HGRCPATH'].split(pycompat.ospathsep):
>                   if not p:
> @@ -86,5 +90,8 @@ def rccomponents():
>                   _rccomponents.extend(('path', p) for p in _expandrcpath(p))
>           else:
> -            paths = defaultrcpath() + systemrcpath() + userrcpath()
> +            paths = defaultrcpath() + systemrcpath()
>               _rccomponents = [('path', os.path.normpath(p)) for p in paths]
> +            _rccomponents.append(envrc)
> +            paths = userrcpath()
> +            _rccomponents.extend(('path', os.path.normpath(p)) for p in paths)

This line is essentially repeated from above... I think it could be 
factored out in a future clean-up.

>       return _rccomponents
> diff --git a/mercurial/ui.py b/mercurial/ui.py
> --- a/mercurial/ui.py
> +++ b/mercurial/ui.py
> @@ -212,8 +212,18 @@ class ui(object):
>           """Create a ui and load global and user configs"""
>           u = cls()
> -        # we always trust global config files
> +        # we always trust global config files and environment variables
>           for t, f in rcutil.rccomponents():
>               if t == 'path':
>                   u.readconfig(f, trust=True)
> +            elif t == 'items':
> +                sections = set()
> +                for section, name, value, source in f:
> +                    # do not set u._ocfg

This comment doesn't explain why, so it's not very helpful.

> +                    # XXX clean this up once immutable config object is a thing
> +                    u._tcfg.set(section, name, value, source)
> +                    u._ucfg.set(section, name, value, source)
> +                    sections.add(section)
> +                for section in sections:
> +                    u.fixconfig(section=section)
>               else:
>                   raise error.ProgrammingError('unknown rctype: %s' % t)
> diff --git a/tests/test-config-env.py b/tests/test-config-env.py
> new file mode 100644
> --- /dev/null
> +++ b/tests/test-config-env.py
> @@ -0,0 +1,48 @@
> +# Test the config layer generated by environment variables
> +
> +from __future__ import absolute_import, print_function
> +
> +import os
> +
> +from mercurial import (
> +    encoding,
> +    rcutil,
> +    ui as uimod,
> +)
> +
> +testtmp = encoding.environ['TESTTMP']
> +
> +# prepare hgrc files
> +def join(name):
> +    return os.path.join(testtmp, name)
> +
> +with open(join('sysrc'), 'w') as f:
> +    f.write('[ui]\neditor=e0\n[pager]\npager=p0\n')
> +
> +with open(join('userrc'), 'w') as f:
> +    f.write('[ui]\neditor=e1')
> +
> +# replace rcpath functions so they point to the files above
> +def systemrcpath():
> +    return [join('sysrc')]
> +
> +def userrcpath():
> +    return [join('userrc')]
> +
> +rcutil.systemrcpath = systemrcpath
> +rcutil.userrcpath = userrcpath
> +os.path.isdir = lambda x: False # hack: do not load default.d/*.rc
> +
> +# utility to print configs
> +def printconfigs(env):
> +    encoding.environ = env
> +    rcutil._rccomponents = None # reset cache
> +    ui = uimod.ui.load()
> +    for section, name, value in ui.walkconfig():
> +        source = ui.configsource(section, name)
> +        print('%s.%s=%s # %s' % (section, name, value, source))
> +    print('')
> +
> +# environment variable overrides
> +printconfigs({})
> +printconfigs({'EDITOR': 'e2', 'PAGER': 'p2'})
> diff --git a/tests/test-config-env.py.out b/tests/test-config-env.py.out
> new file mode 100644
> --- /dev/null
> +++ b/tests/test-config-env.py.out
> @@ -0,0 +1,6 @@
> +pager.pager=p0 # $TESTTMP/sysrc:4
> +ui.editor=e1 # $TESTTMP/userrc:2
> +
> +pager.pager=p2 # $PAGER
> +ui.editor=e1 # $TESTTMP/userrc:2
> +
> diff --git a/tests/test-config.t b/tests/test-config.t
> --- a/tests/test-config.t
> +++ b/tests/test-config.t
> @@ -165,2 +165,16 @@ edit failure
>     abort: edit failed: false exited with status 1
>     [255]
> +
> +config affected by environment variables
> +
> +  $ EDITOR=e1 VISUAL=e2 hg config --debug | grep 'ui\.editor'
> +  $VISUAL: ui.editor=e2
> +
> +  $ VISUAL=e2 hg config --debug --config ui.editor=e3 | grep 'ui\.editor'
> +  --config: ui.editor=e3
> +
> +  $ PAGER=p1 hg config --debug | grep 'pager\.pager'
> +  $PAGER: pager.pager=p1
> +
> +  $ PAGER=p1 hg config --debug --config pager.pager=p2 | grep 'pager\.pager'
> +  --config: pager.pager=p2
>