Mercurial > hg
view mercurial/state.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 | 8ced4ca30ea1 |
children | 9d3721552b6c |
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# state.py - writing and reading state files in Mercurial # # Copyright 2018 Pulkit Goyal <pulkitmgoyal@gmail.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. """ This file contains class to wrap the state for commands and other related logic. All the data related to the command state is stored as dictionary in the object. The class has methods using which the data can be stored to disk in a file under .hg/ directory. We store the data on disk in cbor, for which we use the CBOR format to encode the data. """ import contextlib from .i18n import _ from . import ( error, pycompat, util, ) from .utils import cborutil if pycompat.TYPE_CHECKING: from typing import ( Any, Dict, ) for t in (Any, Dict): assert t class cmdstate: """a wrapper class to store the state of commands like `rebase`, `graft`, `histedit`, `shelve` etc. Extensions can also use this to write state files. All the data for the state is stored in the form of key-value pairs in a dictionary. The class object can write all the data to a file in .hg/ directory and can populate the object data reading that file. Uses cbor to serialize and deserialize data while writing and reading from disk. """ def __init__(self, repo, fname): """repo is the repo object fname is the file name in which data should be stored in .hg directory """ self._repo = repo self.fname = fname def read(self): # type: () -> Dict[bytes, Any] """read the existing state file and return a dict of data stored""" return self._read() def save(self, version, data): """write all the state data stored to .hg/<filename> file we use third-party library cbor to serialize data to write in the file. """ if not isinstance(version, int): raise error.ProgrammingError( b"version of state file should be an integer" ) with self._repo.vfs(self.fname, b'wb', atomictemp=True) as fp: fp.write(b'%d\n' % version) for chunk in cborutil.streamencode(data): fp.write(chunk) def _read(self): """reads the state file and returns a dictionary which contain data in the same format as it was before storing""" with self._repo.vfs(self.fname, b'rb') as fp: try: int(fp.readline()) except ValueError: raise error.CorruptedState( b"unknown version of state file found" ) return cborutil.decodeall(fp.read())[0] def delete(self): """drop the state file if exists""" util.unlinkpath(self._repo.vfs.join(self.fname), ignoremissing=True) def exists(self): """check whether the state file exists or not""" return self._repo.vfs.exists(self.fname) class _statecheck: """a utility class that deals with multistep operations like graft, histedit, bisect, update etc and check whether such commands are in an unfinished conditition or not and return appropriate message and hint. It also has the ability to register and determine the states of any new multistep operation or multistep command extension. """ def __init__( self, opname, fname, clearable, allowcommit, reportonly, continueflag, stopflag, childopnames, cmdmsg, cmdhint, statushint, abortfunc, continuefunc, ): self._opname = opname self._fname = fname self._clearable = clearable self._allowcommit = allowcommit self._reportonly = reportonly self._continueflag = continueflag self._stopflag = stopflag self._childopnames = childopnames self._delegating = False self._cmdmsg = cmdmsg self._cmdhint = cmdhint self._statushint = statushint self.abortfunc = abortfunc self.continuefunc = continuefunc def statusmsg(self): """returns the hint message corresponding to the command for hg status --verbose """ if not self._statushint: hint = _( b'To continue: hg %s --continue\n' b'To abort: hg %s --abort' ) % (self._opname, self._opname) if self._stopflag: hint = hint + ( _(b'\nTo stop: hg %s --stop') % (self._opname) ) return hint return self._statushint def hint(self): """returns the hint message corresponding to an interrupted operation """ if not self._cmdhint: if not self._stopflag: return _(b"use 'hg %s --continue' or 'hg %s --abort'") % ( self._opname, self._opname, ) else: return _( b"use 'hg %s --continue', 'hg %s --abort', " b"or 'hg %s --stop'" ) % ( self._opname, self._opname, self._opname, ) return self._cmdhint def msg(self): """returns the status message corresponding to the command""" if not self._cmdmsg: return _(b'%s in progress') % (self._opname) return self._cmdmsg def continuemsg(self): """returns appropriate continue message corresponding to command""" return _(b'hg %s --continue') % (self._opname) def isunfinished(self, repo): """determines whether a multi-step operation is in progress or not """ if self._opname == b'merge': return len(repo[None].parents()) > 1 elif self._delegating: return False else: return repo.vfs.exists(self._fname) # A list of statecheck objects for multistep operations like graft. _unfinishedstates = [] _unfinishedstatesbyname = {} def addunfinished( opname, fname, clearable=False, allowcommit=False, reportonly=False, continueflag=False, stopflag=False, childopnames=None, cmdmsg=b"", cmdhint=b"", statushint=b"", abortfunc=None, continuefunc=None, ): """this registers a new command or operation to unfinishedstates opname is the name the command or operation fname is the file name in which data should be stored in .hg directory. It is None for merge command. clearable boolean determines whether or not interrupted states can be cleared by running `hg update -C .` which in turn deletes the state file. allowcommit boolean decides whether commit is allowed during interrupted state or not. reportonly flag is used for operations like bisect where we just need to detect the operation using 'hg status --verbose' continueflag is a boolean determines whether or not a command supports `--continue` option or not. stopflag is a boolean that determines whether or not a command supports --stop flag childopnames is a list of other opnames this op uses as sub-steps of its own execution. They must already be added. cmdmsg is used to pass a different status message in case standard message of the format "abort: cmdname in progress" is not desired. cmdhint is used to pass a different hint message in case standard message of the format "To continue: hg cmdname --continue To abort: hg cmdname --abort" is not desired. statushint is used to pass a different status message in case standard message of the format ('To continue: hg cmdname --continue' 'To abort: hg cmdname --abort') is not desired abortfunc stores the function required to abort an unfinished state. continuefunc stores the function required to finish an interrupted operation. """ childopnames = childopnames or [] statecheckobj = _statecheck( opname, fname, clearable, allowcommit, reportonly, continueflag, stopflag, childopnames, cmdmsg, cmdhint, statushint, abortfunc, continuefunc, ) if opname == b'merge': _unfinishedstates.append(statecheckobj) else: # This check enforces that for any op 'foo' which depends on op 'bar', # 'foo' comes before 'bar' in _unfinishedstates. This ensures that # getrepostate() always returns the most specific applicable answer. for childopname in childopnames: if childopname not in _unfinishedstatesbyname: raise error.ProgrammingError( _(b'op %s depends on unknown op %s') % (opname, childopname) ) _unfinishedstates.insert(0, statecheckobj) if opname in _unfinishedstatesbyname: raise error.ProgrammingError(_(b'op %s registered twice') % opname) _unfinishedstatesbyname[opname] = statecheckobj def _getparentandchild(opname, childopname): p = _unfinishedstatesbyname.get(opname, None) if not p: raise error.ProgrammingError(_(b'unknown op %s') % opname) if childopname not in p._childopnames: raise error.ProgrammingError( _(b'op %s does not delegate to %s') % (opname, childopname) ) c = _unfinishedstatesbyname[childopname] return p, c @contextlib.contextmanager def delegating(repo, opname, childopname): """context wrapper for delegations from opname to childopname. requires that childopname was specified when opname was registered. Usage: def my_command_foo_that_uses_rebase(...): ... with state.delegating(repo, 'foo', 'rebase'): _run_rebase(...) ... """ p, c = _getparentandchild(opname, childopname) if p._delegating: raise error.ProgrammingError( _(b'cannot delegate from op %s recursively') % opname ) p._delegating = True try: yield except error.ConflictResolutionRequired as e: # Rewrite conflict resolution advice for the parent opname. if e.opname == childopname: raise error.ConflictResolutionRequired(opname) raise e finally: p._delegating = False def ischildunfinished(repo, opname, childopname): """Returns true if both opname and childopname are unfinished.""" p, c = _getparentandchild(opname, childopname) return (p._delegating or p.isunfinished(repo)) and c.isunfinished(repo) def continuechild(ui, repo, opname, childopname): """Checks that childopname is in progress, and continues it.""" p, c = _getparentandchild(opname, childopname) if not ischildunfinished(repo, opname, childopname): raise error.ProgrammingError( _(b'child op %s of parent %s is not unfinished') % (childopname, opname) ) if not c.continuefunc: raise error.ProgrammingError( _(b'op %s has no continue function') % childopname ) return c.continuefunc(ui, repo) addunfinished( b'update', fname=b'updatestate', clearable=True, cmdmsg=_(b'last update was interrupted'), cmdhint=_(b"use 'hg update' to get a consistent checkout"), statushint=_(b"To continue: hg update ."), ) addunfinished( b'bisect', fname=b'bisect.state', allowcommit=True, reportonly=True, cmdhint=_(b"use 'hg bisect --reset'"), statushint=_( b'To mark the changeset good: hg bisect --good\n' b'To mark the changeset bad: hg bisect --bad\n' b'To abort: hg bisect --reset\n' ), ) def getrepostate(repo): # experimental config: commands.status.skipstates skip = set(repo.ui.configlist(b'commands', b'status.skipstates')) for state in _unfinishedstates: if state._opname in skip: continue if state.isunfinished(repo): return (state._opname, state.statusmsg())