mercurial/demandimport.py
author Angel Ezquerra <angel.ezquerra@gmail.com>
Thu, 13 Dec 2012 23:37:53 +0100
changeset 18109 9e3910db4e78
parent 15096 868282fa29d8
child 19932 e3a5922e18c3
permissions -rw-r--r--
subrepo: append subrepo path to subrepo error messages This change appends the subrepo path to subrepo errors. That is, when there is an error performing an operation a subrepo, rather than displaying a message such as: pushing subrepo MYSUBREPO to PATH searching for changes abort: push creates new remote head HEADHASH! hint: did you forget to merge? use push -f to force mercurial will show: pushing subrepo MYSUBREPO to PATH searching for changes abort: push creates new remote head HEADHASH! (in subrepo MYSUBREPO) hint: did you forget to merge? use push -f to force The rationale for this change is that the current error messages make it hard for TortoiseHg (and similar tools) to tell the user which subrepo caused the push failure. The "(in subrepo MYSUBREPO)" message has been added to those subrepo methods were it made sense (by using a decorator). We avoid appending "(in subrepo XXX)" multiple times when subrepos are nexted by throwing a "SubrepoAbort" exception after the extra message is appended. The decorator will then "ignore" (i.e. just re-raise) the exception and never add the message again. A small drawback of this method is that part of the exception trace is lost when the exception is catched and re-raised by the annotatesubrepoerror decorator. Also, because the state() function already printed the subrepo path when it threw an error, that error has been changed to avoid duplicating the subrepo path in the error message. Note that I have also updated several subrepo related tests to reflect these changes.

# demandimport.py - global demand-loading of modules for Mercurial
#
# Copyright 2006, 2007 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.

'''
demandimport - automatic demandloading of modules

To enable this module, do:

  import demandimport; demandimport.enable()

Imports of the following forms will be demand-loaded:

  import a, b.c
  import a.b as c
  from a import b,c # a will be loaded immediately

These imports will not be delayed:

  from a import *
  b = __import__(a)
'''

import __builtin__
_origimport = __import__

nothing = object()

try:
    _origimport(__builtin__.__name__, {}, {}, None, -1)
except TypeError: # no level argument
    def _import(name, globals, locals, fromlist, level):
        "call _origimport with no level argument"
        return _origimport(name, globals, locals, fromlist)
else:
    _import = _origimport

class _demandmod(object):
    """module demand-loader and proxy"""
    def __init__(self, name, globals, locals):
        if '.' in name:
            head, rest = name.split('.', 1)
            after = [rest]
        else:
            head = name
            after = []
        object.__setattr__(self, "_data", (head, globals, locals, after))
        object.__setattr__(self, "_module", None)
    def _extend(self, name):
        """add to the list of submodules to load"""
        self._data[3].append(name)
    def _load(self):
        if not self._module:
            head, globals, locals, after = self._data
            mod = _origimport(head, globals, locals)
            # load submodules
            def subload(mod, p):
                h, t = p, None
                if '.' in p:
                    h, t = p.split('.', 1)
                if getattr(mod, h, nothing) is nothing:
                    setattr(mod, h, _demandmod(p, mod.__dict__, mod.__dict__))
                elif t:
                    subload(getattr(mod, h), t)

            for x in after:
                subload(mod, x)

            # are we in the locals dictionary still?
            if locals and locals.get(head) == self:
                locals[head] = mod
            object.__setattr__(self, "_module", mod)

    def __repr__(self):
        if self._module:
            return "<proxied module '%s'>" % self._data[0]
        return "<unloaded module '%s'>" % self._data[0]
    def __call__(self, *args, **kwargs):
        raise TypeError("%s object is not callable" % repr(self))
    def __getattribute__(self, attr):
        if attr in ('_data', '_extend', '_load', '_module'):
            return object.__getattribute__(self, attr)
        self._load()
        return getattr(self._module, attr)
    def __setattr__(self, attr, val):
        self._load()
        setattr(self._module, attr, val)

def _demandimport(name, globals=None, locals=None, fromlist=None, level=-1):
    if not locals or name in ignore or fromlist == ('*',):
        # these cases we can't really delay
        return _import(name, globals, locals, fromlist, level)
    elif not fromlist:
        # import a [as b]
        if '.' in name: # a.b
            base, rest = name.split('.', 1)
            # email.__init__ loading email.mime
            if globals and globals.get('__name__', None) == base:
                return _import(name, globals, locals, fromlist, level)
            # if a is already demand-loaded, add b to its submodule list
            if base in locals:
                if isinstance(locals[base], _demandmod):
                    locals[base]._extend(rest)
                return locals[base]
        return _demandmod(name, globals, locals)
    else:
        if level != -1:
            # from . import b,c,d or from .a import b,c,d
            return _origimport(name, globals, locals, fromlist, level)
        # from a import b,c,d
        mod = _origimport(name, globals, locals)
        # recurse down the module chain
        for comp in name.split('.')[1:]:
            if getattr(mod, comp, nothing) is nothing:
                setattr(mod, comp, _demandmod(comp, mod.__dict__, mod.__dict__))
            mod = getattr(mod, comp)
        for x in fromlist:
            # set requested submodules for demand load
            if getattr(mod, x, nothing) is nothing:
                setattr(mod, x, _demandmod(x, mod.__dict__, locals))
        return mod

ignore = [
    '_hashlib',
    '_xmlplus',
    'fcntl',
    'win32com.gen_py',
    '_winreg', # 2.7 mimetypes needs immediate ImportError
    'pythoncom',
    # imported by tarfile, not available under Windows
    'pwd',
    'grp',
    # imported by profile, itself imported by hotshot.stats,
    # not available under Windows
    'resource',
    # this trips up many extension authors
    'gtk',
    # setuptools' pkg_resources.py expects "from __main__ import x" to
    # raise ImportError if x not defined
    '__main__',
    '_ssl', # conditional imports in the stdlib, issue1964
    'rfc822',
    'mimetools',
    ]

def enable():
    "enable global demand-loading of modules"
    __builtin__.__import__ = _demandimport

def disable():
    "disable global demand-loading of modules"
    __builtin__.__import__ = _origimport