Mercurial > hg
view mercurial/scmposix.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 | 7a4143428db7 |
children | 18c8c18993f0 |
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import array import errno import fcntl import os import sys from typing import ( List, Tuple, ) from .pycompat import getattr from . import ( encoding, pycompat, util, ) if pycompat.TYPE_CHECKING: from . import ui as uimod # BSD 'more' escapes ANSI color sequences by default. This can be disabled by # $MORE variable, but there's no compatible option with Linux 'more'. Given # OS X is widely used and most modern Unix systems would have 'less', setting # 'less' as the default seems reasonable. fallbackpager = b'less' def _rcfiles(path: bytes) -> List[bytes]: rcs = [os.path.join(path, b'hgrc')] rcdir = os.path.join(path, b'hgrc.d') try: rcs.extend( [ os.path.join(rcdir, f) for f, kind in sorted(util.listdir(rcdir)) if f.endswith(b".rc") ] ) except OSError: pass return rcs def systemrcpath() -> List[bytes]: path = [] if pycompat.sysplatform == b'plan9': root = b'lib/mercurial' else: root = b'etc/mercurial' # old mod_python does not set sys.argv if len(getattr(sys, 'argv', [])) > 0: p = os.path.dirname(os.path.dirname(pycompat.sysargv[0])) if p != b'/': path.extend(_rcfiles(os.path.join(p, root))) path.extend(_rcfiles(b'/' + root)) return path def userrcpath() -> List[bytes]: if pycompat.sysplatform == b'plan9': return [encoding.environ[b'home'] + b'/lib/hgrc'] elif pycompat.isdarwin: return [os.path.expanduser(b'~/.hgrc')] else: confighome = encoding.environ.get(b'XDG_CONFIG_HOME') if confighome is None or not os.path.isabs(confighome): confighome = os.path.expanduser(b'~/.config') return [ os.path.expanduser(b'~/.hgrc'), os.path.join(confighome, b'hg', b'hgrc'), ] def termsize(ui: "uimod.ui") -> Tuple[int, int]: try: import termios TIOCGWINSZ = termios.TIOCGWINSZ # unavailable on IRIX (issue3449) except (AttributeError, ImportError): return 80, 24 for dev in (ui.ferr, ui.fout, ui.fin): try: try: fd = dev.fileno() except AttributeError: continue if not os.isatty(fd): continue arri = fcntl.ioctl(fd, TIOCGWINSZ, b'\0' * 8) height, width = array.array('h', arri)[:2] if width > 0 and height > 0: return width, height except ValueError: pass except IOError as e: if e.errno == errno.EINVAL: pass else: raise return 80, 24