Mercurial > hg
view mercurial/error.py @ 29375:fcaf20175b1b
demandimport: delay loading for "from a import b" with absolute_import
Before this patch, "from a import b" doesn't delay loading module "b",
if absolute_import is enabled, even though "from . import b" does.
For example:
- it is assumed that extension X has "from P import M" for module M
under package P with absolute_import feature
- if importing module M is already delayed before loading extension
X, loading module M in extension X is delayed until actually
referring
util, cmdutil, scmutil or so of Mercurial itself should be
imported by "from . import M" style before loading extension X
- otherwise, module M is loaded immediately at loading extension X,
even if extension X itself isn't used at that "hg" command invocation
Some minor modules (e.g. filemerge or so) of Mercurial itself
aren't imported by "from . import M" style before loading
extension X. And of course, external libraries aren't, too.
This might cause startup performance problem of hg command, because
many bundled extensions already enable absolute_import feature.
To delay loading module for "from a import b" with absolute_import
feature, this patch does below in "from a (or .a) import b" with
absolute_import case:
1. import root module of "name" by system built-in __import__
(referred as _origimport)
2. recurse down the module chain for hierarchical "name"
This logic can be shared with non absolute_import
case. Therefore, this patch also centralizes it into chainmodules().
3. and fall through to process elements in "fromlist" for the leaf
module of "name"
Processing elements in "fromlist" is executed in the code path
after "if _pypy: .... else: ..." clause. Therefore, this patch
replaces "if _pypy:" with "elif _pypy:" to share it.
At 4f1144c3c72b introducing original "work around" for "from a import
b" case, elements in "fromlist" were imported with "level=level". But
"level" might be grater than 1 (e.g. level=2 in "from .. import b"
case) at demandimport() invocation, and importing direct sub-module in
"fromlist" with level grater than 1 causes unexpected result.
IMHO, this seems main reason of "errors for unknown reason" described
in 4f1144c3c72b, and we don't have to worry about it, because this
issue was already fixed by 78d05778907b.
This is reason why this patch removes "errors for unknown reasons"
comment.
author | FUJIWARA Katsunori <foozy@lares.dti.ne.jp> |
---|---|
date | Sun, 19 Jun 2016 02:17:33 +0900 |
parents | 13bb8de97f87 |
children | 945b4c14c570 |
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# 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. """ from __future__ import absolute_import # 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(HintException): """Exception raised when a command requires human intervention.""" class Abort(HintException): """Raised if a command needs to print an error and exit.""" 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 ambigious""" 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(HintException): """Exception raised when a remote repo reports failure""" class ParseError(HintException): """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.""" 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 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 # LockError is for errors while acquiring the lock -- this is unrelated class LockInheritanceContractViolation(RuntimeError): 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 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, 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""" 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. """ class InvalidBundleSpecification(Exception): """error raised when a bundle specification is invalid. This is used for syntax errors as opposed to support errors. """ class UnsupportedBundleSpecification(Exception): """error raised when a bundle specification is not supported."""