annotate mercurial/error.py @ 45059:79f6f9fa18c1

documentation: add some internals documentation about bid merge

This is an important algorithm that was only documented on the wiki so far.

Some update to the algorithm (and associated doc) is to expected in the future
since the bid merge algorithm is bug-ridden when it comes to file deletion comes
to play.

Differential Revision: https://phab.mercurial-scm.org/D8711

# 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('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


class SidedataHashError(RevlogError):
    def __init__(self, key, expected, got):
        self.sidedatakey = key
        self.expecteddigest = expected
        self.actualdigest = got


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, b'%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

    if pycompat.ispy3:

        def __str__(self):
            # the output would be unreadable if the message was translated,
            # but do not replace it with encoding.strfromlocal(), which
            # may raise another exception.
            return pycompat.sysstr(self.__bytes__())


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, _(b'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, _(b"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 = b' '.join(self.recordtypes)
        Abort.__init__(
            self,
            _(b'unsupported merge state records: %s') % s,
            hint=_(
                b'see https://mercurial-scm.org/wiki/MergeStateRecords for '
                b'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, b'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 = b'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(b"%s=%r" % (par, pycompat.maybebytestr(val)))
        if entries:
            msg = b'%s - %s' % (msg, b', '.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, b'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, b'%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