Mercurial > hg
view mercurial/config.py @ 50336:cf4d2f31660d stable
chg: populate CHGHG if not set
Normally, chg determines which `hg` executable to use by first consulting the
`$CHGHG` and `$HG` environment variables, and if neither are present defaults
to the `hg` found in the user's `$PATH`. If built with the `HGPATHREL` compiler
flag, chg will instead assume that there exists an `hg` executable in the same
directory as the `chg` binary and attempt to use that.
This can cause problems in situations where there are multiple actively-used
Mercurial installations on the same system. When a `chg` client connects to a
running command server, the server process performs some basic validation to
determine whether a new command server needs to be spawned. These checks include
things like checking certain "sensitive" environment variables and config
sections, as well as checking whether the mtime of the extensions, hg's
`__version__.py` module, and the Python interpreter have changed.
Crucially, the command server doesn't explicitly check whether the executable it
is running from matches the executable that the `chg` client would have
otherwise invoked had there been no existing command server process. Without
`HGPATHREL`, this still gets implicitly checked during the validation step,
because the only way to specify an alternate hg executable (apart from `$PATH`)
is via the `$CHGHG` and `$HG` environment variables, both of which are checked.
With `HGPATHREL`, however, the command server has no way of knowing which hg
executable the client would have run. This means that a client located at
`/version_B/bin/chg` will happily connect to a command server running
`/version_A/bin/hg` instead of `/version_B/bin/hg` as expected. A simple
solution is to have the client set `$CHGHG` itself, which then allows the
command server's environment validation to work as intended.
I have tested this manually using two locally built hg installations and it
seems to work with no ill effects. That said, I'm not sure how to write an
automated test for this since the `chg` available to the tests isn't even built
with the `HGPATHREL` compiler flag to begin with.
author | Arun Kulshreshtha <akulshreshtha@janestreet.com> |
---|---|
date | Mon, 27 Mar 2023 17:30:14 -0400 |
parents | 642e31cb55f0 |
children | 18c8c18993f0 |
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# config.py - configuration parsing for Mercurial # # Copyright 2009 Olivia Mackall <olivia@selenic.com> and others # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. import errno import os from .i18n import _ from .pycompat import getattr from . import ( encoding, error, util, ) class config: def __init__(self, data=None): self._current_source_level = 0 self._data = {} self._unset = [] if data: for k in data._data: self._data[k] = data[k].copy() self._current_source_level = data._current_source_level + 1 def new_source(self): """increment the source counter This is used to define source priority when reading""" self._current_source_level += 1 def copy(self): return config(self) def __contains__(self, section): return section in self._data def hasitem(self, section, item): return item in self._data.get(section, {}) def __getitem__(self, section): return self._data.get(section, {}) def __iter__(self): for d in self.sections(): yield d def update(self, src): current_level = self._current_source_level current_level += 1 max_level = self._current_source_level for s, n in src._unset: ds = self._data.get(s, None) if ds is not None and n in ds: self._data[s] = ds.preparewrite() del self._data[s][n] for s in src: ds = self._data.get(s, None) if ds: self._data[s] = ds.preparewrite() else: self._data[s] = util.cowsortdict() for k, v in src._data[s].items(): value, source, level = v level += current_level max_level = max(level, current_level) self._data[s][k] = (value, source, level) self._current_source_level = max_level def _get(self, section, item): return self._data.get(section, {}).get(item) def get(self, section, item, default=None): result = self._get(section, item) if result is None: return default return result[0] def backup(self, section, key): """return a tuple allowing restore to reinstall a previous value The main reason we need it is because it handles the "no data" case. """ try: item = self._data[section][key] except KeyError: return (section, key) else: return (section, key) + item def source(self, section, item): result = self._get(section, item) if result is None: return b"" return result[1] def level(self, section, item): result = self._get(section, item) if result is None: return None return result[2] def sections(self): return sorted(self._data.keys()) def items(self, section): items = self._data.get(section, {}).items() return [(k, v[0]) for (k, v) in items] def set(self, section, item, value, source=b""): assert not isinstance( section, str ), b'config section may not be unicode strings on Python 3' assert not isinstance( item, str ), b'config item may not be unicode strings on Python 3' assert not isinstance( value, str ), b'config values may not be unicode strings on Python 3' if section not in self: self._data[section] = util.cowsortdict() else: self._data[section] = self._data[section].preparewrite() self._data[section][item] = (value, source, self._current_source_level) def alter(self, section, key, new_value): """alter a value without altering its source or level This method is meant to be used by `ui.fixconfig` only.""" item = self._data[section][key] size = len(item) new_item = (new_value,) + item[1:] assert len(new_item) == size self._data[section][key] = new_item def restore(self, data): """restore data returned by self.backup""" if len(data) != 2: # restore old data section, key = data[:2] item = data[2:] self._data[section] = self._data[section].preparewrite() self._data[section][key] = item else: # no data before, remove everything section, item = data if section in self._data: self._data[section].pop(item, None) def parse(self, src, data, sections=None, remap=None, include=None): sectionre = util.re.compile(br'\[([^\[]+)\]') itemre = util.re.compile(br'([^=\s][^=]*?)\s*=\s*(.*\S|)') contre = util.re.compile(br'\s+(\S|\S.*\S)\s*$') emptyre = util.re.compile(br'(;|#|\s*$)') commentre = util.re.compile(br'(;|#)') unsetre = util.re.compile(br'%unset\s+(\S+)') includere = util.re.compile(br'%include\s+(\S|\S.*\S)\s*$') section = b"" item = None line = 0 cont = False if remap: section = remap.get(section, section) for l in data.splitlines(True): line += 1 if line == 1 and l.startswith(b'\xef\xbb\xbf'): # Someone set us up the BOM l = l[3:] if cont: if commentre.match(l): continue m = contre.match(l) if m: if sections and section not in sections: continue v = self.get(section, item) + b"\n" + m.group(1) self.set(section, item, v, b"%s:%d" % (src, line)) continue item = None cont = False m = includere.match(l) if m and include: expanded = util.expandpath(m.group(1)) try: include(expanded, remap=remap, sections=sections) except IOError as inst: if inst.errno != errno.ENOENT: raise error.ConfigError( _(b"cannot include %s (%s)") % (expanded, encoding.strtolocal(inst.strerror)), b"%s:%d" % (src, line), ) continue if emptyre.match(l): continue m = sectionre.match(l) if m: section = m.group(1) if remap: section = remap.get(section, section) if section not in self: self._data[section] = util.cowsortdict() continue m = itemre.match(l) if m: item = m.group(1) cont = True if sections and section not in sections: continue self.set(section, item, m.group(2), b"%s:%d" % (src, line)) continue m = unsetre.match(l) if m: name = m.group(1) if sections and section not in sections: continue if self.get(section, name) is not None: self._data[section] = self._data[section].preparewrite() del self._data[section][name] self._unset.append((section, name)) continue message = l.rstrip() if l.startswith(b' '): message = b"unexpected leading whitespace: %s" % message raise error.ConfigError(message, (b"%s:%d" % (src, line))) def read(self, path, fp=None, sections=None, remap=None): self.new_source() if not fp: fp = util.posixfile(path, b'rb') assert ( getattr(fp, 'mode', 'rb') == 'rb' ), b'config files must be opened in binary mode, got fp=%r mode=%r' % ( fp, fp.mode, ) dir = os.path.dirname(path) def include(rel, remap, sections): abs = os.path.normpath(os.path.join(dir, rel)) self.read(abs, remap=remap, sections=sections) # anything after the include has a higher level self.new_source() self.parse( path, fp.read(), sections=sections, remap=remap, include=include )