import-checker: establish modern import convention
We introduce a new convention for declaring imports and enforce it via
the import checker script.
The new convention is only active when absolute imports are used, which is
currently nowhere. Keying off "from __future__ import absolute_import" to
engage the new import convention seems like the easiest solution. It is
also beneficial for Mercurial to use this mode because it means less work
and ambiguity for the importer and potentially better performance due to
fewer stat() system calls because the importer won't look for modules in
relative paths unless explicitly asked.
Once all files are converted to use absolute import, we can refactor
this code to again only have a single import convention and we can
require use of absolute import in the style checker.
The rules for the new convention are documented in the docstring of the
added function. Tests have been added to test-module-imports.t. Some
tests are sensitive to newlines and source column position, which makes
docstring testing difficult and/or impossible.
# error.py - Mercurial exceptions
#
# Copyright 2005-2008 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""Mercurial exceptions.
This allows us to catch exceptions at higher levels without forcing
imports.
"""
# Do not import anything here, please
class HintException(Exception):
def __init__(self, *args, **kw):
Exception.__init__(self, *args)
self.hint = kw.get('hint')
class RevlogError(HintException):
pass
class FilteredIndexError(IndexError):
pass
class LookupError(RevlogError, KeyError):
def __init__(self, name, index, message):
self.name = name
self.index = index
# this can't be called 'message' because at least some installs of
# Python 2.6+ complain about the 'message' property being deprecated
self.lookupmessage = message
if isinstance(name, str) and len(name) == 20:
from node import short
name = short(name)
RevlogError.__init__(self, '%s@%s: %s' % (index, name, message))
def __str__(self):
return RevlogError.__str__(self)
class FilteredLookupError(LookupError):
pass
class ManifestLookupError(LookupError):
pass
class CommandError(Exception):
"""Exception raised on errors in parsing the command line."""
class InterventionRequired(Exception):
"""Exception raised when a command requires human intervention."""
class Abort(HintException):
"""Raised if a command needs to print an error and exit."""
pass
class HookAbort(Abort):
"""raised when a validation hook fails, aborting an operation
Exists to allow more specialized catching."""
pass
class ConfigError(Abort):
"""Exception raised when parsing config files"""
class OutOfBandError(Exception):
"""Exception raised when a remote repo reports failure"""
def __init__(self, *args, **kw):
Exception.__init__(self, *args)
self.hint = kw.get('hint')
class ParseError(Exception):
"""Raised when parsing config files and {rev,file}sets (msg[, pos])"""
class UnknownIdentifier(ParseError):
"""Exception raised when a {rev,file}set references an unknown identifier"""
def __init__(self, function, symbols):
from i18n import _
ParseError.__init__(self, _("unknown identifier: %s") % function)
self.function = function
self.symbols = symbols
class RepoError(HintException):
pass
class RepoLookupError(RepoError):
pass
class FilteredRepoLookupError(RepoLookupError):
pass
class CapabilityError(RepoError):
pass
class RequirementError(RepoError):
"""Exception raised if .hg/requires has an unknown entry."""
pass
class LockError(IOError):
def __init__(self, errno, strerror, filename, desc):
IOError.__init__(self, errno, strerror, filename)
self.desc = desc
class LockHeld(LockError):
def __init__(self, errno, filename, desc, locker):
LockError.__init__(self, errno, 'Lock held', filename, desc)
self.locker = locker
class LockUnavailable(LockError):
pass
class ResponseError(Exception):
"""Raised to print an error with part of output and exit."""
class UnknownCommand(Exception):
"""Exception raised if command is not in the command table."""
class AmbiguousCommand(Exception):
"""Exception raised if command shortcut matches more than one command."""
# derived from KeyboardInterrupt to simplify some breakout code
class SignalInterrupt(KeyboardInterrupt):
"""Exception raised on SIGTERM and SIGHUP."""
class SignatureError(Exception):
pass
class PushRaced(RuntimeError):
"""An exception raised during unbundling that indicate a push race"""
# bundle2 related errors
class BundleValueError(ValueError):
"""error raised when bundle2 cannot be processed"""
class UnsupportedPartError(BundleValueError):
def __init__(self, parttype=None, params=()):
self.parttype = parttype
self.params = params
if self.parttype is None:
msg = 'Stream Parameter'
else:
msg = parttype
if self.params:
msg = '%s - %s' % (msg, ', '.join(self.params))
ValueError.__init__(self, msg)
class ReadOnlyPartError(RuntimeError):
"""error raised when code tries to alter a part being generated"""
pass
class PushkeyFailed(Abort):
"""error raised when a pushkey part failed to update a value"""
def __init__(self, partid, namespace=None, key=None, new=None, old=None,
ret=None):
self.partid = partid
self.namespace = namespace
self.key = key
self.new = new
self.old = old
self.ret = ret
# no i18n expected to be processed into a better message
Abort.__init__(self, 'failed to update value for "%s/%s"'
% (namespace, key))
class CensoredNodeError(RevlogError):
"""error raised when content verification fails on a censored node
Also contains the tombstone data substituted for the uncensored data.
"""
def __init__(self, filename, node, tombstone):
from node import short
RevlogError.__init__(self, '%s:%s' % (filename, short(node)))
self.tombstone = tombstone
class CensoredBaseError(RevlogError):
"""error raised when a delta is rejected because its base is censored
A delta based on a censored revision must be formed as single patch
operation which replaces the entire base with new content. This ensures
the delta may be applied by clones which have not censored the base.
"""