mercurial/loggingutil.py

pull: improved message issued in case of failed update

When running `hg pull --update`, the update step may fail. Nothing in the error
message help to understand the abort is related to the secondary step (update)
instead of the primary step (pull).

We now add some information to the error message to clarify it comes from the
update part. It is useful in various situation (uncommitted changes blocking the
update, update to hidden destination, etc...)

The pull output is updated from:

  $ hg pull ../repo-Bob --rev 956063ac4557 --update
  pulling from ../repo-Bob
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 0 changes to 2 files (+1 heads)
  (2 other changesets obsolete on arrival)
  abort: filtered revision '6'!

to:

  $ hg pull ../repo-Bob --rev 956063ac4557 --update
  pulling from ../repo-Bob
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 0 changes to 2 files (+1 heads)
  (2 other changesets obsolete on arrival)
  abort: cannot update to target: filtered revision '6'!

(I am not sure why the actual error, "filtered revision '6'", is not using the
more modern format mentioning the obsolescence fate of '6')

# loggingutil.py - utility for logging events
#
# Copyright 2010 Nicolas Dumazet
# Copyright 2013 Facebook, Inc.
#
# 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 errno

from . import (
    pycompat,
)

from .utils import (
    dateutil,
    procutil,
    stringutil,
)

def openlogfile(ui, vfs, name, maxfiles=0, maxsize=0):
    """Open log file in append mode, with optional rotation

    If maxsize > 0, the log file will be rotated up to maxfiles.
    """
    def rotate(oldpath, newpath):
        try:
            vfs.unlink(newpath)
        except OSError as err:
            if err.errno != errno.ENOENT:
                ui.debug("warning: cannot remove '%s': %s\n" %
                         (newpath, err.strerror))
        try:
            if newpath:
                vfs.rename(oldpath, newpath)
        except OSError as err:
            if err.errno != errno.ENOENT:
                ui.debug("warning: cannot rename '%s' to '%s': %s\n" %
                         (newpath, oldpath, err.strerror))

    if maxsize > 0:
        try:
            st = vfs.stat(name)
        except OSError:
            pass
        else:
            if st.st_size >= maxsize:
                path = vfs.join(name)
                for i in pycompat.xrange(maxfiles - 1, 1, -1):
                    rotate(oldpath='%s.%d' % (path, i - 1),
                           newpath='%s.%d' % (path, i))
                rotate(oldpath=path,
                       newpath=maxfiles > 0 and path + '.1')
    return vfs(name, 'a', makeparentdirs=False)

def _formatlogline(msg):
    date = dateutil.datestr(format=b'%Y/%m/%d %H:%M:%S')
    pid = procutil.getpid()
    return b'%s (%d)> %s' % (date, pid, msg)

def _matchevent(event, tracked):
    return b'*' in tracked or event in tracked

class filelogger(object):
    """Basic logger backed by physical file with optional rotation"""

    def __init__(self, vfs, name, tracked, maxfiles=0, maxsize=0):
        self._vfs = vfs
        self._name = name
        self._trackedevents = set(tracked)
        self._maxfiles = maxfiles
        self._maxsize = maxsize

    def tracked(self, event):
        return _matchevent(event, self._trackedevents)

    def log(self, ui, event, msg, opts):
        line = _formatlogline(msg)
        try:
            with openlogfile(ui, self._vfs, self._name,
                             maxfiles=self._maxfiles,
                             maxsize=self._maxsize) as fp:
                fp.write(line)
        except IOError as err:
            ui.debug(b'cannot write to %s: %s\n'
                     % (self._name, stringutil.forcebytestr(err)))

class fileobjectlogger(object):
    """Basic logger backed by file-like object"""

    def __init__(self, fp, tracked):
        self._fp = fp
        self._trackedevents = set(tracked)

    def tracked(self, event):
        return _matchevent(event, self._trackedevents)

    def log(self, ui, event, msg, opts):
        line = _formatlogline(msg)
        try:
            self._fp.write(line)
            self._fp.flush()
        except IOError as err:
            ui.debug(b'cannot write to %s: %s\n'
                     % (stringutil.forcebytestr(self._fp.name),
                        stringutil.forcebytestr(err)))

class proxylogger(object):
    """Forward log events to another logger to be set later"""

    def __init__(self):
        self.logger = None

    def tracked(self, event):
        return self.logger is not None and self.logger.tracked(event)

    def log(self, ui, event, msg, opts):
        assert self.logger is not None
        self.logger.log(ui, event, msg, opts)