error: implement __str__ on RevlogError to fix some output defects on Py3

We open-code encoding.unimethod here to avoid cycles, and do a local
import of encoding when someone str()s a RevlogError. It's not my
favorite solution, but it gets the job done.

Differential Revision: https://phab.mercurial-scm.org/D5426

mercurial/error.py

@@ -1,336 +1,344
 # error.py - Mercurial exceptions
 #
 # Copyright 2005-2008 Matt Mackall <[e-mail]>
 #
 # 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.
 """
 
 from __future__ import absolute_import
 
 # Do not import anything but pycompat here, please
 from . import pycompat
 
 def _tobytes(exc):
     """Byte-stringify exception in the same way as BaseException_str()"""
     if not exc.args:
         return b''
     if len(exc.args) == 1:
         return pycompat.bytestr(exc.args[0])
     return b'(%s)' % b', '.join(b"'%s'" % pycompat.bytestr(a) for a in exc.args)
 
 class Hint(object):
     """Mix-in to provide a hint of an error
 
     This should come first in the inheritance list to consume a hint and
     pass remaining arguments to the exception class.
     """
     def __init__(self, *args, **kw):
         self.hint = kw.pop(r'hint', None)
         super(Hint, self).__init__(*args, **kw)
 
 class StorageError(Hint, Exception):
     """Raised when an error occurs in a storage layer.
 
     Usually subclassed by a storage-specific exception.
     """
     __bytes__ = _tobytes
 
 class RevlogError(StorageError):
     __bytes__ = _tobytes
 
+    def __str__(self):
+        # avoid cycle, and directly implement unimethod for this
+        # __str__ to allow delaying the import of encoding until
+        # someone actually wants the __str__ of a RevlogError (which
+        # should be very rare).
+        from . import encoding
+        return encoding.unifromlocal(_tobytes(self))
+
 class FilteredIndexError(IndexError):
     __bytes__ = _tobytes
 
 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, bytes) and len(name) == 20:
             from .node import short
             name = short(name)
         RevlogError.__init__(self, '%s@%s: %s' % (index, name, message))
 
     def __bytes__(self):
         return RevlogError.__bytes__(self)
 
     def __str__(self):
         return RevlogError.__str__(self)
 
 class AmbiguousPrefixLookupError(LookupError):
     pass
 
 class FilteredLookupError(LookupError):
     pass
 
 class ManifestLookupError(LookupError):
     pass
 
 class CommandError(Exception):
     """Exception raised on errors in parsing the command line."""
     __bytes__ = _tobytes
 
 class InterventionRequired(Hint, Exception):
     """Exception raised when a command requires human intervention."""
     __bytes__ = _tobytes
 
 class Abort(Hint, Exception):
     """Raised if a command needs to print an error and exit."""
     __bytes__ = _tobytes
 
 class HookLoadError(Abort):
     """raised when loading a hook fails, aborting an operation
 
     Exists to allow more specialized catching."""
 
 class HookAbort(Abort):
     """raised when a validation hook fails, aborting an operation
 
     Exists to allow more specialized catching."""
 
 class ConfigError(Abort):
     """Exception raised when parsing config files"""
 
 class UpdateAbort(Abort):
     """Raised when an update is aborted for destination issue"""
 
 class MergeDestAbort(Abort):
     """Raised when an update is aborted for destination issues"""
 
 class NoMergeDestAbort(MergeDestAbort):
     """Raised when an update is aborted because there is nothing to merge"""
 
 class ManyMergeDestAbort(MergeDestAbort):
     """Raised when an update is aborted because destination is ambiguous"""
 
 class ResponseExpected(Abort):
     """Raised when an EOF is received for a prompt"""
     def __init__(self):
         from .i18n import _
         Abort.__init__(self, _('response expected'))
 
 class OutOfBandError(Hint, Exception):
     """Exception raised when a remote repo reports failure"""
     __bytes__ = _tobytes
 
 class ParseError(Hint, Exception):
     """Raised when parsing config files and {rev,file}sets (msg[, pos])"""
     __bytes__ = _tobytes
 
 class PatchError(Exception):
     __bytes__ = _tobytes
 
 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(Hint, Exception):
     __bytes__ = _tobytes
 
 class RepoLookupError(RepoError):
     pass
 
 class FilteredRepoLookupError(RepoLookupError):
     pass
 
 class CapabilityError(RepoError):
     pass
 
 class RequirementError(RepoError):
     """Exception raised if .hg/requires has an unknown entry."""
 
 class StdioError(IOError):
     """Raised if I/O to stdout or stderr fails"""
 
     def __init__(self, err):
         IOError.__init__(self, err.errno, err.strerror)
 
     # no __bytes__() because error message is derived from the standard IOError
 
 class UnsupportedMergeRecords(Abort):
     def __init__(self, recordtypes):
         from .i18n import _
         self.recordtypes = sorted(recordtypes)
         s = ' '.join(self.recordtypes)
         Abort.__init__(
             self, _('unsupported merge state records: %s') % s,
             hint=_('see https://mercurial-scm.org/wiki/MergeStateRecords for '
                    'more information'))
 
 class UnknownVersion(Abort):
     """generic exception for aborting from an encounter with an unknown version
     """
 
     def __init__(self, msg, hint=None, version=None):
         self.version = version
         super(UnknownVersion, self).__init__(msg, hint=hint)
 
 class LockError(IOError):
     def __init__(self, errno, strerror, filename, desc):
         IOError.__init__(self, errno, strerror, filename)
         self.desc = desc
 
     # no __bytes__() because error message is derived from the standard IOError
 
 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
 
 # LockError is for errors while acquiring the lock -- this is unrelated
 class LockInheritanceContractViolation(RuntimeError):
     __bytes__ = _tobytes
 
 class ResponseError(Exception):
     """Raised to print an error with part of output and exit."""
     __bytes__ = _tobytes
 
 class UnknownCommand(Exception):
     """Exception raised if command is not in the command table."""
     __bytes__ = _tobytes
 
 class AmbiguousCommand(Exception):
     """Exception raised if command shortcut matches more than one command."""
     __bytes__ = _tobytes
 
 # derived from KeyboardInterrupt to simplify some breakout code
 class SignalInterrupt(KeyboardInterrupt):
     """Exception raised on SIGTERM and SIGHUP."""
 
 class SignatureError(Exception):
     __bytes__ = _tobytes
 
 class PushRaced(RuntimeError):
     """An exception raised during unbundling that indicate a push race"""
     __bytes__ = _tobytes
 
 class ProgrammingError(Hint, RuntimeError):
     """Raised if a mercurial (core or extension) developer made a mistake"""
 
     def __init__(self, msg, *args, **kwargs):
         # On Python 3, turn the message back into a string since this is
         # an internal-only error that won't be printed except in a
         # stack traces.
         msg = pycompat.sysstr(msg)
         super(ProgrammingError, self).__init__(msg, *args, **kwargs)
 
     __bytes__ = _tobytes
 
 class WdirUnsupported(Exception):
     """An exception which is raised when 'wdir()' is not supported"""
     __bytes__ = _tobytes
 
 # bundle2 related errors
 class BundleValueError(ValueError):
     """error raised when bundle2 cannot be processed"""
     __bytes__ = _tobytes
 
 class BundleUnknownFeatureError(BundleValueError):
     def __init__(self, parttype=None, params=(), values=()):
         self.parttype = parttype
         self.params = params
         self.values = values
         if self.parttype is None:
             msg = 'Stream Parameter'
         else:
             msg = parttype
         entries = self.params
         if self.params and self.values:
             assert len(self.params) == len(self.values)
             entries = []
             for idx, par in enumerate(self.params):
                 val = self.values[idx]
                 if val is None:
                     entries.append(val)
                 else:
                     entries.append("%s=%r" % (par, pycompat.maybebytestr(val)))
         if entries:
             msg = '%s - %s' % (msg, ', '.join(entries))
         ValueError.__init__(self, msg)
 
 class ReadOnlyPartError(RuntimeError):
     """error raised when code tries to alter a part being generated"""
     __bytes__ = _tobytes
 
 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(StorageError):
     """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
         StorageError.__init__(self, '%s:%s' % (filename, short(node)))
         self.tombstone = tombstone
 
 class CensoredBaseError(StorageError):
     """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.
     """
 
 class InvalidBundleSpecification(Exception):
     """error raised when a bundle specification is invalid.
 
     This is used for syntax errors as opposed to support errors.
     """
     __bytes__ = _tobytes
 
 class UnsupportedBundleSpecification(Exception):
     """error raised when a bundle specification is not supported."""
     __bytes__ = _tobytes
 
 class CorruptedState(Exception):
     """error raised when a command is not able to read its state from file"""
     __bytes__ = _tobytes
 
 class PeerTransportError(Abort):
     """Transport-level I/O error when communicating with a peer repo."""
 
 class InMemoryMergeConflictsError(Exception):
     """Exception raised when merge conflicts arose during an in-memory merge."""
     __bytes__ = _tobytes
 
 class WireprotoCommandError(Exception):
     """Represents an error during execution of a wire protocol command.
 
     Should only be thrown by wire protocol version 2 commands.
 
     The error is a formatter string and an optional iterable of arguments.
     """
     def __init__(self, message, args=None):
         self.message = message
         self.messageargs = args