[Python-checkins] cpython: Issue #18070: importlib.util.module_for_loader() now sets __loader__
brett.cannon
python-checkins at python.org
Wed May 29 00:36:06 CEST 2013
http://hg.python.org/cpython/rev/185a0e649fb8
changeset: 83963:185a0e649fb8
user: Brett Cannon <brett at python.org>
date: Tue May 28 18:35:54 2013 -0400
summary:
Issue #18070: importlib.util.module_for_loader() now sets __loader__
and __package__ unconditionally in order to do the right thing for
reloading.
files:
Doc/library/importlib.rst | 22 +-
Doc/whatsnew/3.4.rst | 7 +-
Lib/importlib/_bootstrap.py | 35 +-
Lib/test/test_importlib/test_util.py | 13 +-
Misc/NEWS | 3 +
Python/importlib.h | 6879 ++++++-------
6 files changed, 3468 insertions(+), 3491 deletions(-)
diff --git a/Doc/library/importlib.rst b/Doc/library/importlib.rst
--- a/Doc/library/importlib.rst
+++ b/Doc/library/importlib.rst
@@ -811,12 +811,11 @@
The decorated method will take in the **name** of the module to be loaded
as expected for a :term:`loader`. If the module is not found in
- :data:`sys.modules` then a new one is constructed with its
- :attr:`__name__` attribute set to **name**, :attr:`__loader__` set to
- **self**, and :attr:`__package__` set based on what
- :meth:`importlib.abc.InspectLoader.is_package` returns (if available). If a
- new module is not needed then the module found in :data:`sys.modules` will
- be passed into the method.
+ :data:`sys.modules` then a new one is constructed. Regardless of where the
+ module came from, :attr:`__loader__` set to **self** and :attr:`__package__`
+ is set based on what :meth:`importlib.abc.InspectLoader.is_package` returns
+ (if available). These attributes are set unconditionally to support
+ reloading.
If an exception is raised by the decorated method and a module was added to
:data:`sys.modules` it will be removed to prevent a partially initialized
@@ -831,6 +830,10 @@
:attr:`__loader__` and :attr:`__package__` are automatically set
(when possible).
+ .. versionchanged:: 3.4
+ Set :attr:`__loader__` :attr:`__package__` unconditionally to support
+ reloading.
+
.. decorator:: set_loader
A :term:`decorator` for :meth:`importlib.abc.Loader.load_module`
@@ -843,12 +846,13 @@
.. note::
As this decorator sets :attr:`__loader__` after loading the module, it is
recommended to use :func:`module_for_loader` instead when appropriate.
+ This decorator is also redundant as of Python 3.3 as import itself will
+ set these attributes post-import if necessary.
.. versionchanged:: 3.4
Set ``__loader__`` if set to ``None``, as if the attribute does not
exist.
-
.. decorator:: set_package
A :term:`decorator` for :meth:`importlib.abc.Loader.load_module` to set the :attr:`__package__` attribute on the returned module. If :attr:`__package__`
@@ -856,4 +860,6 @@
.. note::
As this decorator sets :attr:`__package__` after loading the module, it is
- recommended to use :func:`module_for_loader` instead when appropriate.
+ recommended to use :func:`module_for_loader` instead when appropriate. As
+ of Python 3.3 this decorator is also redundant as import will set
+ :attr:`__package__` post-import if necessary.
diff --git a/Doc/whatsnew/3.4.rst b/Doc/whatsnew/3.4.rst
--- a/Doc/whatsnew/3.4.rst
+++ b/Doc/whatsnew/3.4.rst
@@ -250,4 +250,9 @@
* The module type now initializes the :attr:`__package__` and :attr:`__loader__`
attributes to ``None`` by default. To determine if these attributes were set
in a backwards-compatible fashion, use e.g.
- ``getattr(module, '__loader__', None) is not None``.
\ No newline at end of file
+ ``getattr(module, '__loader__', None) is not None``.
+
+* :meth:`importlib.util.module_for_loader` now sets ``__loader__`` and
+ ``__package__`` unconditionally to properly support reloading. If this is not
+ desired then you will need to set these attributes manually. You can use
+ :class:`importlib.util.ModuleManager` for module management.
diff --git a/Lib/importlib/_bootstrap.py b/Lib/importlib/_bootstrap.py
--- a/Lib/importlib/_bootstrap.py
+++ b/Lib/importlib/_bootstrap.py
@@ -37,23 +37,13 @@
return _relax_case
-# TODO: Expose from marshal
def _w_long(x):
- """Convert a 32-bit integer to little-endian.
-
- XXX Temporary until marshal's long functions are exposed.
-
- """
+ """Convert a 32-bit integer to little-endian."""
return (int(x) & 0xFFFFFFFF).to_bytes(4, 'little')
-# TODO: Expose from marshal
def _r_long(int_bytes):
- """Convert 4 bytes in little-endian to an integer.
-
- XXX Temporary until marshal's long function are exposed.
-
- """
+ """Convert 4 bytes in little-endian to an integer."""
return int.from_bytes(int_bytes, 'little')
@@ -569,17 +559,7 @@
"""
def module_for_loader_wrapper(self, fullname, *args, **kwargs):
- module = sys.modules.get(fullname)
- is_reload = module is not None
- if not is_reload:
- # This must be done before open() is called as the 'io' module
- # implicitly imports 'locale' and would otherwise trigger an
- # infinite loop.
- module = new_module(fullname)
- # This must be done before putting the module in sys.modules
- # (otherwise an optimization shortcut in import.c becomes wrong)
- module.__initializing__ = True
- sys.modules[fullname] = module
+ with ModuleManager(fullname) as module:
module.__loader__ = self
try:
is_package = self.is_package(fullname)
@@ -590,17 +570,8 @@
module.__package__ = fullname
else:
module.__package__ = fullname.rpartition('.')[0]
- else:
- module.__initializing__ = True
- try:
# If __package__ was not set above, __import__() will do it later.
return fxn(self, module, *args, **kwargs)
- except:
- if not is_reload:
- del sys.modules[fullname]
- raise
- finally:
- module.__initializing__ = False
_wrap(module_for_loader_wrapper, fxn)
return module_for_loader_wrapper
diff --git a/Lib/test/test_importlib/test_util.py b/Lib/test/test_importlib/test_util.py
--- a/Lib/test/test_importlib/test_util.py
+++ b/Lib/test/test_importlib/test_util.py
@@ -85,12 +85,23 @@
def test_reload(self):
# Test that a module is reused if already in sys.modules.
+ class FakeLoader:
+ def is_package(self, name):
+ return True
+ @util.module_for_loader
+ def load_module(self, module):
+ return module
name = 'a.b.c'
module = imp.new_module('a.b.c')
+ module.__loader__ = 42
+ module.__package__ = 42
with test_util.uncache(name):
sys.modules[name] = module
- returned_module = self.return_module(name)
+ loader = FakeLoader()
+ returned_module = loader.load_module(name)
self.assertIs(returned_module, sys.modules[name])
+ self.assertEqual(module.__loader__, loader)
+ self.assertEqual(module.__package__, name)
def test_new_module_failure(self):
# Test that a module is removed from sys.modules if added but an
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -96,6 +96,9 @@
Library
-------
+- Issue #18070: Have importlib.util.module_for_loader() set attributes
+ unconditionally in order to properly support reloading.
+
- Add importlib.util.ModuleManager as a context manager to provide the proper
module object to load.
diff --git a/Python/importlib.h b/Python/importlib.h
--- a/Python/importlib.h
+++ b/Python/importlib.h
[stripped]
--
Repository URL: http://hg.python.org/cpython
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