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Issue #20383: Introduce importlib.util.module_from_spec().

Browse source 
Along the way, dismantle importlib._bootstrap._SpecMethods as it was
no longer relevant and constructing the new function required
partially dismantling the class anyway.
This commit is contained in:
Brett Cannon 2014-05-30 14:55:29 -04:00
parent c8f0d6ebfc
commit 2a17bde930
17 changed files with 4536 additions and 4736 deletions
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385
Lib/importlib/_bootstrap.py
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@ -9,7 +9,7 @@ work. One should use importlib as the public-facing version of this module.
#
# IMPORTANT: Whenever making changes to this module, be sure to run
# a top-level make in order to get the frozen version of the module
# update. Not doing so will result in the Makefile to fail for
# updated. Not doing so will result in the Makefile to fail for
# all others who don't have a ./python around to freeze the module
# in the early stages of compilation.
#
@ -581,20 +581,19 @@ def _find_module_shim(self, fullname):
return loader
def _load_module_shim(self, fullname):
def _load_module_shim(spec, fullname):
"""Load the specified module into sys.modules and return it.
This method is deprecated. Use loader.exec_module instead.
"""
spec = spec_from_loader(fullname, self)
methods = _SpecMethods(spec)
spec = spec_from_loader(fullname, spec)
if fullname in sys.modules:
module = sys.modules[fullname]
methods.exec(module)
_exec(spec, module)
return sys.modules[fullname]
else:
return methods.load()
return _load(spec)
def _validate_bytecode_header(data, source_stats=None, name=None, path=None):
@ -705,7 +704,7 @@ def _module_repr(module):
pass
else:
if spec is not None:
return _SpecMethods(spec).module_repr()
return _module_repr_from_spec(spec)
# We could use module.__class__.__name__ instead of 'module' in the
# various repr permutations.
@ -991,234 +990,182 @@ def _spec_from_module(module, loader=None, origin=None):
return spec
class _SpecMethods:
def _init_module_attrs(spec, module, *, override=False):
# The passed-in module may be not support attribute assignment,
# in which case we simply don't set the attributes.
# __name__
if (override or getattr(module, '__name__', None) is None):
try:
module.__name__ = spec.name
except AttributeError:
pass
# __loader__
if override or getattr(module, '__loader__', None) is None:
loader = spec.loader
if loader is None:
# A backward compatibility hack.
if spec.submodule_search_locations is not None:
loader = _NamespaceLoader.__new__(_NamespaceLoader)
loader._path = spec.submodule_search_locations
try:
module.__loader__ = loader
except AttributeError:
pass
# __package__
if override or getattr(module, '__package__', None) is None:
try:
module.__package__ = spec.parent
except AttributeError:
pass
# __spec__
try:
module.__spec__ = spec
except AttributeError:
pass
# __path__
if override or getattr(module, '__path__', None) is None:
if spec.submodule_search_locations is not None:
try:
module.__path__ = spec.submodule_search_locations
except AttributeError:
pass
# __file__/__cached__
if spec.has_location:
if override or getattr(module, '__file__', None) is None:
try:
module.__file__ = spec.origin
except AttributeError:
pass
"""Convenience wrapper around spec objects to provide spec-specific
methods."""
if override or getattr(module, '__cached__', None) is None:
if spec.cached is not None:
try:
module.__cached__ = spec.cached
except AttributeError:
pass
return module
# The various spec_from_* functions could be made factory methods here.
def __init__(self, spec):
self.spec = spec
def module_from_spec(spec):
"""Create a module based on the provided spec."""
# Typically loaders will not implement create_module().
module = None
if hasattr(spec.loader, 'create_module'):
# If create_module() returns `None` then it means default
# module creation should be used.
module = spec.loader.create_module(spec)
if module is None:
module = _new_module(spec.name)
_init_module_attrs(spec, module)
return module
def module_repr(self):
"""Return the repr to use for the module."""
# We mostly replicate _module_repr() using the spec attributes.
spec = self.spec
name = '?' if spec.name is None else spec.name
if spec.origin is None:
if spec.loader is None:
return '<module {!r}>'.format(name)
else:
return '<module {!r} ({!r})>'.format(name, spec.loader)
def _module_repr_from_spec(spec):
"""Return the repr to use for the module."""
# We mostly replicate _module_repr() using the spec attributes.
name = '?' if spec.name is None else spec.name
if spec.origin is None:
if spec.loader is None:
return '<module {!r}>'.format(name)
else:
if spec.has_location:
return '<module {!r} from {!r}>'.format(name, spec.origin)
else:
return '<module {!r} ({})>'.format(spec.name, spec.origin)
return '<module {!r} ({!r})>'.format(name, spec.loader)
else:
if spec.has_location:
return '<module {!r} from {!r}>'.format(name, spec.origin)
else:
return '<module {!r} ({})>'.format(spec.name, spec.origin)
def init_module_attrs(self, module, *, _override=False, _force_name=True):
"""Set the module's attributes.
All missing import-related module attributes will be set. Here
is how the spec attributes map onto the module:
# Used by importlib.reload() and _load_module_shim().
def _exec(spec, module):
"""Execute the spec in an existing module's namespace."""
name = spec.name
_imp.acquire_lock()
with _ModuleLockManager(name):
if sys.modules.get(name) is not module:
msg = 'module {!r} not in sys.modules'.format(name)
raise ImportError(msg, name=name)
if spec.loader is None:
if spec.submodule_search_locations is None:
raise ImportError('missing loader', name=spec.name)
# namespace package
_init_module_attrs(spec, module, override=True)
return module
_init_module_attrs(spec, module, override=True)
if not hasattr(spec.loader, 'exec_module'):
# (issue19713) Once BuiltinImporter and ExtensionFileLoader
# have exec_module() implemented, we can add a deprecation
# warning here.
spec.loader.load_module(name)
else:
spec.loader.exec_module(module)
return sys.modules[name]
spec.name -> module.__name__
spec.loader -> module.__loader__
spec.parent -> module.__package__
spec -> module.__spec__
Optional:
spec.origin -> module.__file__ (if spec.set_fileattr is true)
spec.cached -> module.__cached__ (if __file__ also set)
spec.submodule_search_locations -> module.__path__ (if set)
"""
spec = self.spec
# The passed in module may be not support attribute assignment,
# in which case we simply don't set the attributes.
# __name__
if (_override or _force_name or
getattr(module, '__name__', None) is None):
try:
module.__name__ = spec.name
except AttributeError:
pass
# __loader__
if _override or getattr(module, '__loader__', None) is None:
loader = spec.loader
if loader is None:
# A backward compatibility hack.
if spec.submodule_search_locations is not None:
loader = _NamespaceLoader.__new__(_NamespaceLoader)
loader._path = spec.submodule_search_locations
try:
module.__loader__ = loader
except AttributeError:
pass
# __package__
if _override or getattr(module, '__package__', None) is None:
try:
module.__package__ = spec.parent
except AttributeError:
pass
# __spec__
def _load_backward_compatible(spec):
# (issue19713) Once BuiltinImporter and ExtensionFileLoader
# have exec_module() implemented, we can add a deprecation
# warning here.
spec.loader.load_module(spec.name)
# The module must be in sys.modules at this point!
module = sys.modules[spec.name]
if getattr(module, '__loader__', None) is None:
try:
module.__loader__ = spec.loader
except AttributeError:
pass
if getattr(module, '__package__', None) is None:
try:
# Since module.__path__ may not line up with
# spec.submodule_search_paths, we can't necessarily rely
# on spec.parent here.
module.__package__ = module.__name__
if not hasattr(module, '__path__'):
module.__package__ = spec.name.rpartition('.')[0]
except AttributeError:
pass
if getattr(module, '__spec__', None) is None:
try:
module.__spec__ = spec
except AttributeError:
pass
return module
# __path__
if _override or getattr(module, '__path__', None) is None:
if spec.submodule_search_locations is not None:
try:
module.__path__ = spec.submodule_search_locations
except AttributeError:
pass
def _load_unlocked(spec):
# A helper for direct use by the import system.
if spec.loader is not None:
# not a namespace package
if not hasattr(spec.loader, 'exec_module'):
return _load_backward_compatible(spec)
if spec.has_location:
# __file__
if _override or getattr(module, '__file__', None) is None:
try:
module.__file__ = spec.origin
except AttributeError:
pass
# __cached__
if _override or getattr(module, '__cached__', None) is None:
if spec.cached is not None:
try:
module.__cached__ = spec.cached
except AttributeError:
pass
def create(self):
"""Return a new module to be loaded.
The import-related module attributes are also set with the
appropriate values from the spec.
"""
spec = self.spec
# Typically loaders will not implement create_module().
if hasattr(spec.loader, 'create_module'):
# If create_module() returns `None` it means the default
# module creation should be used.
module = spec.loader.create_module(spec)
module = module_from_spec(spec)
with _installed_safely(module):
if spec.loader is None:
if spec.submodule_search_locations is None:
raise ImportError('missing loader', name=spec.name)
# A namespace package so do nothing.
else:
module = None
if module is None:
# This must be done before open() is ever called as the 'io'
# module implicitly imports 'locale' and would otherwise
# trigger an infinite loop.
module = _new_module(spec.name)
self.init_module_attrs(module)
return module
spec.loader.exec_module(module)
def _exec(self, module):
"""Do everything necessary to execute the module.
# We don't ensure that the import-related module attributes get
# set in the sys.modules replacement case. Such modules are on
# their own.
return sys.modules[spec.name]
The namespace of `module` is used as the target of execution.
This method uses the loader's `exec_module()` method.
# A method used during testing of _load_unlocked() and by
# _load_module_shim().
def _load(spec):
"""Return a new module object, loaded by the spec's loader.
"""
self.spec.loader.exec_module(module)
The module is not added to its parent.
# Used by importlib.reload() and _load_module_shim().
def exec(self, module):
"""Execute the spec in an existing module's namespace."""
name = self.spec.name
_imp.acquire_lock()
with _ModuleLockManager(name):
if sys.modules.get(name) is not module:
msg = 'module {!r} not in sys.modules'.format(name)
raise ImportError(msg, name=name)
if self.spec.loader is None:
if self.spec.submodule_search_locations is None:
raise ImportError('missing loader', name=self.spec.name)
# namespace package
self.init_module_attrs(module, _override=True)
return module
self.init_module_attrs(module, _override=True)
if not hasattr(self.spec.loader, 'exec_module'):
# (issue19713) Once BuiltinImporter and ExtensionFileLoader
# have exec_module() implemented, we can add a deprecation
# warning here.
self.spec.loader.load_module(name)
else:
self._exec(module)
return sys.modules[name]
If a module is already in sys.modules, that existing module gets
clobbered.
def _load_backward_compatible(self):
# (issue19713) Once BuiltinImporter and ExtensionFileLoader
# have exec_module() implemented, we can add a deprecation
# warning here.
spec = self.spec
spec.loader.load_module(spec.name)
# The module must be in sys.modules at this point!
module = sys.modules[spec.name]
if getattr(module, '__loader__', None) is None:
try:
module.__loader__ = spec.loader
except AttributeError:
pass
if getattr(module, '__package__', None) is None:
try:
# Since module.__path__ may not line up with
# spec.submodule_search_paths, we can't necessarily rely
# on spec.parent here.
module.__package__ = module.__name__
if not hasattr(module, '__path__'):
module.__package__ = spec.name.rpartition('.')[0]
except AttributeError:
pass
if getattr(module, '__spec__', None) is None:
try:
module.__spec__ = spec
except AttributeError:
pass
return module
def _load_unlocked(self):
# A helper for direct use by the import system.
if self.spec.loader is not None:
# not a namespace package
if not hasattr(self.spec.loader, 'exec_module'):
return self._load_backward_compatible()
module = self.create()
with _installed_safely(module):
if self.spec.loader is None:
if self.spec.submodule_search_locations is None:
raise ImportError('missing loader', name=self.spec.name)
# A namespace package so do nothing.
else:
self._exec(module)
# We don't ensure that the import-related module attributes get
# set in the sys.modules replacement case. Such modules are on
# their own.
return sys.modules[self.spec.name]
# A method used during testing of _load_unlocked() and by
# _load_module_shim().
def load(self):
"""Return a new module object, loaded by the spec's loader.
The module is not added to its parent.
If a module is already in sys.modules, that existing module gets
clobbered.
"""
_imp.acquire_lock()
with _ModuleLockManager(self.spec.name):
return self._load_unlocked()
"""
_imp.acquire_lock()
with _ModuleLockManager(spec.name):
return _load_unlocked(spec)
def _fix_up_module(ns, name, pathname, cpathname=None):
@ -1800,7 +1747,7 @@ class _NamespacePath:
self._path.append(item)
# We use this exclusively in init_module_attrs() for backward-compatibility.
# We use this exclusively in module_from_spec() for backward-compatibility.
class _NamespaceLoader:
def __init__(self, name, path, path_finder):
self._path = _NamespacePath(name, path, path_finder)
@ -2224,7 +2171,7 @@ def _find_and_load_unlocked(name, import_):
if spec is None:
raise ImportError(_ERR_MSG.format(name), name=name)
else:
module = _SpecMethods(spec)._load_unlocked()
module = _load_unlocked(spec)
if parent:
# Set the module as an attribute on its parent.
parent_module = sys.modules[parent]
@ -2359,8 +2306,7 @@ def _builtin_from_name(name):
spec = BuiltinImporter.find_spec(name)
if spec is None:
raise ImportError('no built-in module named ' + name)
methods = _SpecMethods(spec)
return methods._load_unlocked()
return _load_unlocked(spec)
def _setup(sys_module, _imp_module):
@ -2391,8 +2337,7 @@ def _setup(sys_module, _imp_module):
else:
continue
spec = _spec_from_module(module, loader)
methods = _SpecMethods(spec)
methods.init_module_attrs(module)
_init_module_attrs(spec, module)
# Directly load built-in modules needed during bootstrap.
self_module = sys.modules[__name__]