view mercurial/rcutil.py @ 37271:0194dac77c93

scmutil: add method for looking up a context given a revision symbol

changectx's constructor currently supports a mix if inputs:

  * integer revnums
  * binary nodeids
  * '.', 'tip', 'null'
  * stringified revnums
  * namespaced identifiers (e.g. bookmarks and tags)
  * hex nodeids
  * partial hex nodeids

The first two are always internal [1]. The other five can be specified
by the user. The third type ('.', 'tip', 'null') often comes from
either the user or internal callers. We probably have some internal
callers that pass hex nodeids too, perhaps even partial ones
(histedit?). There are only a few callers that pass user-supplied
strings: revsets.stringset, peer.lookup, webutil.changeidctx, and
maybe one or two more.

Supporting this mix of things in the constructor is convenient, but a
bit strange, IMO. For example, if repo[node] is given a node that's
not in the repo, it will first check if it's bookmark etc before
raising an exception. Of course, the risk of it being a bookmark is
extremely small, but it just feels ugly.

Also, a problem with having this code in the constructor (whether it
supports a mix of types or not) is that it's harder to override (I'd
like to override it, and that's how this series started).

This patch starts moving out the handling of user-supplied strings by
introducing scmutil.revsymbol(). So far, that just checks that the
input is indeed a string, and then delegates to repo[symbol]. The
patch also calls it from revsets.stringset to prove that it works.

 [1] Well, you probably can enter a 20-byte binary nodeid on the
     command line, but I don't think we should care to preserve
     support for that.

Differential Revision: https://phab.mercurial-scm.org/D3024

# rcutil.py - utilities about config paths, special config sections etc.
#
#  Copyright Mercurial Contributors
#
# 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 os

from . import (
    encoding,
    pycompat,
    util,
)

if pycompat.iswindows:
    from . import scmwindows as scmplatform
else:
    from . import scmposix as scmplatform

fallbackpager = scmplatform.fallbackpager
systemrcpath = scmplatform.systemrcpath
userrcpath = scmplatform.userrcpath

def _expandrcpath(path):
    '''path could be a file or a directory. return a list of file paths'''
    p = util.expandpath(path)
    if os.path.isdir(p):
        join = os.path.join
        return [join(p, f) for f, k in util.listdir(p) if f.endswith('.rc')]
    return [p]

def envrcitems(env=None):
    '''Return [(section, name, value, source)] config items.

    The config items are extracted from environment variables specified by env,
    used to override systemrc, but not userrc.

    If env is not provided, encoding.environ will be used.
    '''
    if env is None:
        env = encoding.environ
    checklist = [
        ('EDITOR', 'ui', 'editor'),
        ('VISUAL', 'ui', 'editor'),
        ('PAGER', 'pager', 'pager'),
    ]
    result = []
    for envname, section, configname in checklist:
        if envname not in env:
            continue
        result.append((section, configname, env[envname], '$%s' % envname))
    return result

def defaultrcpath():
    '''return rc paths in default.d'''
    path = []
    defaultpath = os.path.join(util.datapath, 'default.d')
    if os.path.isdir(defaultpath):
        path = _expandrcpath(defaultpath)
    return path

def rccomponents():
    '''return an ordered [(type, obj)] about where to load configs.

    respect $HGRCPATH. if $HGRCPATH is empty, only .hg/hgrc of current repo is
    used. if $HGRCPATH is not set, the platform default will be used.

    if a directory is provided, *.rc files under it will be used.

    type could be either 'path' or 'items', if type is 'path', obj is a string,
    and is the config file path. if type is 'items', obj is a list of (section,
    name, value, source) that should fill the config directly.
    '''
    envrc = ('items', envrcitems())

    if 'HGRCPATH' in encoding.environ:
        # 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:
                continue
            _rccomponents.extend(('path', p) for p in _expandrcpath(p))
    else:
        normpaths = lambda paths: [('path', os.path.normpath(p)) for p in paths]
        _rccomponents = normpaths(defaultrcpath() + systemrcpath())
        _rccomponents.append(envrc)
        _rccomponents.extend(normpaths(userrcpath()))
    return _rccomponents

def defaultpagerenv():
    '''return a dict of default environment variables and their values,
    intended to be set before starting a pager.
    '''
    return {'LESS': 'FRX', 'LV': '-c'}