Mercurial > hg
view mercurial/demandimport.py @ 32255:7e35d31b41fd
filemerge: add internal merge tool to dump files forcibly
Internal merge tool :dump implies premerge. Therefore, files aren't
dumped, if premerge runs successfully.
This undocumented behavior might confuse users, if they want to always
dump files. But just making :dump omit premerge might cause backward
compatibility issue for existing automation.
This patch adds new internal merge tool :forcedump, which works as
same as :dump, but omits premerge always.
Internal tools annotated with "nomerge" should merge "change and
delete" correctly, but _forcedump() can't. Therefore, it is annotated
with "mergeonly" to always omit premerge, even though it doesn't merge
files actually.
This patch also adds explanation about premerge to :dump, to clarify
how :dump actually works.
BTW, this patch specifies internal tools with "internal:" prefix in
newly added test scenario in test-merge-tools.t, even though this
prefix is already deprecated. This is only for similarity to other
tests in test-merge-tools.t.
author | FUJIWARA Katsunori <foozy@lares.dti.ne.jp> |
---|---|
date | Sat, 13 May 2017 03:31:42 +0900 |
parents | c939fdce0fde |
children | b2b5605285ec |
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# 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) ''' from __future__ import absolute_import import contextlib import os import sys # __builtin__ in Python 2, builtins in Python 3. try: import __builtin__ as builtins except ImportError: import builtins contextmanager = contextlib.contextmanager _origimport = __import__ nothing = object() # Python 3 doesn't have relative imports nor level -1. level = -1 if sys.version_info[0] >= 3: level = 0 _import = _origimport def _hgextimport(importfunc, name, globals, *args, **kwargs): try: return importfunc(name, globals, *args, **kwargs) except ImportError: if not globals: raise # extensions are loaded with "hgext_" prefix hgextname = 'hgext_%s' % name nameroot = hgextname.split('.', 1)[0] contextroot = globals.get('__name__', '').split('.', 1)[0] if nameroot != contextroot: raise # retry to import with "hgext_" prefix return importfunc(hgextname, globals, *args, **kwargs) class _demandmod(object): """module demand-loader and proxy Specify 1 as 'level' argument at construction, to import module relatively. """ def __init__(self, name, globals, locals, level): if '.' in name: head, rest = name.split('.', 1) after = [rest] else: head = name after = [] object.__setattr__(self, r"_data", (head, globals, locals, after, level, set())) object.__setattr__(self, r"_module", None) def _extend(self, name): """add to the list of submodules to load""" self._data[3].append(name) def _addref(self, name): """Record that the named module ``name`` imports this module. References to this proxy class having the name of this module will be replaced at module load time. We assume the symbol inside the importing module is identical to the "head" name of this module. We don't actually know if "as X" syntax is being used to change the symbol name because this information isn't exposed to __import__. """ self._data[5].add(name) def _load(self): if not self._module: head, globals, locals, after, level, modrefs = self._data mod = _hgextimport(_import, head, globals, locals, None, level) if mod is self: # In this case, _hgextimport() above should imply # _demandimport(). Otherwise, _hgextimport() never # returns _demandmod. This isn't intentional behavior, # in fact. (see also issue5304 for detail) # # If self._module is already bound at this point, self # should be already _load()-ed while _hgextimport(). # Otherwise, there is no way to import actual module # as expected, because (re-)invoking _hgextimport() # should cause same result. # This is reason why _load() returns without any more # setup but assumes self to be already bound. mod = self._module assert mod and mod is not self, "%s, %s" % (self, mod) return # 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__, level=1)) elif t: subload(getattr(mod, h), t) for x in after: subload(mod, x) # Replace references to this proxy instance with the actual module. if locals and locals.get(head) == self: locals[head] = mod for modname in modrefs: modref = sys.modules.get(modname, None) if modref and getattr(modref, head, None) == self: setattr(modref, head, mod) object.__setattr__(self, r"_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', '_addref'): return object.__getattribute__(self, attr) self._load() return getattr(self._module, attr) def __setattr__(self, attr, val): self._load() setattr(self._module, attr, val) _pypy = '__pypy__' in sys.builtin_module_names def _demandimport(name, globals=None, locals=None, fromlist=None, level=level): if not locals or name in ignore or fromlist == ('*',): # these cases we can't really delay return _hgextimport(_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, level) else: # There is a fromlist. # from a import b,c,d # from . import b,c,d # from .a import b,c,d # level == -1: relative and absolute attempted (Python 2 only). # level >= 0: absolute only (Python 2 w/ absolute_import and Python 3). # The modern Mercurial convention is to use absolute_import everywhere, # so modern Mercurial code will have level >= 0. # The name of the module the import statement is located in. globalname = globals.get('__name__') def processfromitem(mod, attr): """Process an imported symbol in the import statement. If the symbol doesn't exist in the parent module, and if the parent module is a package, it must be a module. We set missing modules up as _demandmod instances. """ symbol = getattr(mod, attr, nothing) nonpkg = getattr(mod, '__path__', nothing) is nothing if symbol is nothing: if nonpkg: # do not try relative import, which would raise ValueError, # and leave unknown attribute as the default __import__() # would do. the missing attribute will be detected later # while processing the import statement. return mn = '%s.%s' % (mod.__name__, attr) if mn in ignore: importfunc = _origimport else: importfunc = _demandmod symbol = importfunc(attr, mod.__dict__, locals, level=1) setattr(mod, attr, symbol) # Record the importing module references this symbol so we can # replace the symbol with the actual module instance at load # time. if globalname and isinstance(symbol, _demandmod): symbol._addref(globalname) def chainmodules(rootmod, modname): # recurse down the module chain, and return the leaf module mod = rootmod for comp in modname.split('.')[1:]: if getattr(mod, comp, nothing) is nothing: setattr(mod, comp, _demandmod(comp, mod.__dict__, mod.__dict__, level=1)) mod = getattr(mod, comp) return mod if level >= 0: if name: # "from a import b" or "from .a import b" style rootmod = _hgextimport(_origimport, name, globals, locals, level=level) mod = chainmodules(rootmod, name) elif _pypy: # PyPy's __import__ throws an exception if invoked # with an empty name and no fromlist. Recreate the # desired behaviour by hand. mn = globalname mod = sys.modules[mn] if getattr(mod, '__path__', nothing) is nothing: mn = mn.rsplit('.', 1)[0] mod = sys.modules[mn] if level > 1: mn = mn.rsplit('.', level - 1)[0] mod = sys.modules[mn] else: mod = _hgextimport(_origimport, name, globals, locals, level=level) for x in fromlist: processfromitem(mod, x) return mod # But, we still need to support lazy loading of standard library and 3rd # party modules. So handle level == -1. mod = _hgextimport(_origimport, name, globals, locals) mod = chainmodules(mod, name) for x in fromlist: processfromitem(mod, x) return mod ignore = [ '__future__', '_hashlib', # ImportError during pkg_resources/__init__.py:fixup_namespace_package '_imp', '_xmlplus', 'fcntl', 'nt', # pathlib2 tests the existence of built-in 'nt' module 'win32com.gen_py', 'win32com.shell', # 'appdirs' tries to import win32com.shell '_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 '_sre', # issue4920 'rfc822', 'mimetools', 'sqlalchemy.events', # has import-time side effects (issue5085) # setuptools 8 expects this module to explode early when not on windows 'distutils.msvc9compiler', '__builtin__', 'builtins', 'urwid.command_map', # for pudb ] if _pypy: ignore.extend([ # _ctypes.pointer is shadowed by "from ... import pointer" (PyPy 5) '_ctypes.pointer', ]) def isenabled(): return builtins.__import__ == _demandimport def enable(): "enable global demand-loading of modules" if os.environ.get('HGDEMANDIMPORT') != 'disable': builtins.__import__ = _demandimport def disable(): "disable global demand-loading of modules" builtins.__import__ = _origimport @contextmanager def deactivated(): "context manager for disabling demandimport in 'with' blocks" demandenabled = isenabled() if demandenabled: disable() try: yield finally: if demandenabled: enable()