[Python-checkins] cpython: Issue #15502: Finish bringing importlib.abc in line with the current
brett.cannon
python-checkins at python.org
Fri Aug 10 18:21:23 CEST 2012
http://hg.python.org/cpython/rev/0a75ce232f56
changeset: 78485:0a75ce232f56
parent: 78483:aaa68dce117e
user: Brett Cannon <brett at python.org>
date: Fri Aug 10 12:21:12 2012 -0400
summary:
Issue #15502: Finish bringing importlib.abc in line with the current
state of the import system. Also make importlib.invalidate_caches()
work with sys.meta_path instead of sys.path_importer_cache to
completely separate the path-based import system from the overall
import system.
Patch by Eric Snow.
files:
Doc/library/importlib.rst | 68 +-
Lib/importlib/__init__.py | 6 +-
Lib/importlib/_bootstrap.py | 12 +-
Lib/importlib/abc.py | 42 +-
Lib/test/test_importlib/test_abc.py | 2 +
Lib/test/test_importlib/test_api.py | 10 +-
Misc/NEWS | 3 +
Python/importlib.h | 2362 +++++++-------
8 files changed, 1296 insertions(+), 1209 deletions(-)
diff --git a/Doc/library/importlib.rst b/Doc/library/importlib.rst
--- a/Doc/library/importlib.rst
+++ b/Doc/library/importlib.rst
@@ -102,12 +102,11 @@
.. function:: invalidate_caches()
- Invalidate the internal caches of the finders stored at
- :data:`sys.path_importer_cache`. If a finder implements
- :meth:`abc.Finder.invalidate_caches()` then it will be called to perform the
- invalidation. This function may be needed if some modules are installed
- while your program is running and you expect the program to notice the
- changes.
+ Invalidate the internal caches of finders stored at
+ :data:`sys.meta_path`. If a finder implements ``invalidate_caches()`` then it
+ will be called to perform the invalidation. This function may be needed if
+ some modules are installed while your program is running and you expect the
+ program to notice the changes.
.. versionadded:: 3.3
@@ -129,22 +128,17 @@
implementations should derive from (or register with) the more specific
:class:`MetaPathFinder` or :class:`PathEntryFinder` ABCs.
- .. method:: invalidate_caches()
+ .. method:: find_module(fullname, path=None)
- An optional method which, when called, should invalidate any internal
- cache used by the finder. Used by :func:`invalidate_caches()` when
- invalidating the caches of all cached finders.
-
- .. versionchanged:: 3.3
- The API signatures for meta path finders and path entry finders
- were separated by PEP 420. Accordingly, the Finder ABC no
- longer requires implementation of a ``find_module()`` method.
+ An abstact method for finding a :term:`loader` for the specified
+ module. Originally specified in :pep:`302`, this method was meant
+ for use in :data:`sys.meta_path` and in the path-based import subsystem.
.. class:: MetaPathFinder
- An abstract base class representing a :term:`meta path finder` and
- inheriting from :class:`Finder`.
+ An abstract base class representing a :term:`meta path finder`. For
+ compatibility, this is a subclass of :class:`Finder`.
.. versionadded:: 3.3
@@ -156,20 +150,45 @@
will be the value of :attr:`__path__` from the parent
package. If a loader cannot be found, ``None`` is returned.
+ .. method:: invalidate_caches()
+
+ An optional method which, when called, should invalidate any internal
+ cache used by the finder. Used by :func:`invalidate_caches()` when
+ invalidating the caches of all finders on :data:`sys.meta_path`.
+
.. class:: PathEntryFinder
- An abstract base class representing a :term:`path entry finder` and
- inheriting from :class:`Finder`.
+ An abstract base class representing a :term:`path entry finder`. Though
+ it bears some similarities to :class:`MetaPathFinder`, ``PathEntryFinder``
+ is meant for use only within the path-based import subsystem provided
+ by :class:`PathFinder`. This ABC is a subclass of :class:`Finder` for
+ compatibility.
.. versionadded:: 3.3
.. method:: find_loader(fullname):
An abstract method for finding a :term:`loader` for the specified
- module. Returns a 2-tuple of ``(loader, portion)`` where portion is a
- sequence of file system locations contributing to part of a namespace
- package. The sequence may be empty.
+ module. Returns a 2-tuple of ``(loader, portion)`` where ``portion``
+ is a sequence of file system locations contributing to part of a namespace
+ package. The loader may be ``None`` while specifying ``portion`` to
+ signify the contribution of the file system locations to a namespace
+ package. An empty list can be used for ``portion`` to signify the loader
+ is not part of a package. If ``loader`` is ``None`` and ``portion`` is
+ the empty list then no loader or location for a namespace package were
+ found (i.e. failure to find anything for the module).
+
+ .. method:: find_module(fullname):
+
+ A concrete implementation of :meth:`Finder.find_module` which is
+ equivalent to ``self.find_loader(fullname)[0]``.
+
+ .. method:: invalidate_caches()
+
+ An optional method which, when called, should invalidate any internal
+ cache used by the finder. Used by :meth:`PathFinder.invalidate_caches()`
+ when invalidating the caches of all cached finders.
.. class:: Loader
@@ -638,6 +657,11 @@
module. If no finder is ever found then ``None`` is both stored in
the cache and returned.
+ .. classmethod:: invalidate_caches()
+
+ Call :meth:`importlib.abc.PathEntryFinder.invalidate_caches` on all
+ finders stored in :attr:`sys.path_importer_cache`.
+
.. class:: FileFinder(path, \*loader_details)
diff --git a/Lib/importlib/__init__.py b/Lib/importlib/__init__.py
--- a/Lib/importlib/__init__.py
+++ b/Lib/importlib/__init__.py
@@ -38,9 +38,9 @@
def invalidate_caches():
- """Call the invalidate_caches() method on all finders stored in
- sys.path_importer_caches (where implemented)."""
- for finder in sys.path_importer_cache.values():
+ """Call the invalidate_caches() method on all meta path finders stored in
+ sys.meta_path (where implemented)."""
+ for finder in sys.meta_path:
if hasattr(finder, 'invalidate_caches'):
finder.invalidate_caches()
diff --git a/Lib/importlib/_bootstrap.py b/Lib/importlib/_bootstrap.py
--- a/Lib/importlib/_bootstrap.py
+++ b/Lib/importlib/_bootstrap.py
@@ -1186,6 +1186,14 @@
"""Meta path finder for sys.path and package __path__ attributes."""
@classmethod
+ def invalidate_caches(cls):
+ """Call the invalidate_caches() method on all path entry finders
+ stored in sys.path_importer_caches (where implemented)."""
+ for finder in sys.path_importer_cache.values():
+ if hasattr(finder, 'invalidate_caches'):
+ finder.invalidate_caches()
+
+ @classmethod
def _path_hooks(cls, path):
"""Search sequence of hooks for a finder for 'path'.
@@ -1235,14 +1243,14 @@
portions = []
if loader is not None:
# We found a loader: return it immediately.
- return (loader, namespace_path)
+ return loader, namespace_path
# This is possibly part of a namespace package.
# Remember these path entries (if any) for when we
# create a namespace package, and continue iterating
# on path.
namespace_path.extend(portions)
else:
- return (None, namespace_path)
+ return None, namespace_path
@classmethod
def find_module(cls, fullname, path=None):
diff --git a/Lib/importlib/abc.py b/Lib/importlib/abc.py
--- a/Lib/importlib/abc.py
+++ b/Lib/importlib/abc.py
@@ -25,26 +25,22 @@
class Finder(metaclass=abc.ABCMeta):
- """Common abstract base class for import finders.
+ """Legacy abstract base class for import finders.
- Finder implementations should derive from the more specific
- MetaPathFinder or PathEntryFinder ABCs rather than directly from Finder.
+ It may be subclassed for compatibility with legacy third party
+ reimplementations of the import system. Otherwise, finder
+ implementations should derive from the more specific MetaPathFinder
+ or PathEntryFinder ABCs.
"""
+ @abc.abstractmethod
def find_module(self, fullname, path=None):
- """An optional legacy method that should find a module.
+ """An abstract method that should find a module.
The fullname is a str and the optional path is a str or None.
Returns a Loader object.
-
- The path finder will use this method only if find_loader() does
- not exist. It may optionally be implemented for compatibility
- with legacy third party reimplementations of the import system.
"""
raise NotImplementedError
- # invalidate_caches() is a completely optional method, so no default
- # implementation is provided. See the docs for details.
-
class MetaPathFinder(Finder):
@@ -52,12 +48,18 @@
@abc.abstractmethod
def find_module(self, fullname, path):
- """Abstract method which when implemented should find a module.
+ """Abstract method which, when implemented, should find a module.
The fullname is a str and the path is a str or None.
Returns a Loader object.
"""
raise NotImplementedError
+ def invalidate_caches(self):
+ """An optional method for clearing the finder's cache, if any.
+ This method is used by importlib.invalidate_caches().
+ """
+ return NotImplemented
+
_register(MetaPathFinder, machinery.BuiltinImporter, machinery.FrozenImporter,
machinery.PathFinder, machinery.WindowsRegistryFinder)
@@ -68,13 +70,25 @@
@abc.abstractmethod
def find_loader(self, fullname):
- """Abstract method which when implemented returns a module loader.
+ """Abstract method which, when implemented, returns a module loader.
The fullname is a str. Returns a 2-tuple of (Loader, portion) where
portion is a sequence of file system locations contributing to part of
- a namespace package. The sequence may be empty.
+ a namespace package. The sequence may be empty and the loader may be
+ None.
"""
raise NotImplementedError
+ def find_module(self, fullname):
+ """Compatibility function which is the equivalent of
+ self.find_loader(fullname)[0]."""
+ return self.find_loader(fullname)[0]
+
+ def invalidate_caches(self):
+ """An optional method for clearing the finder's cache, if any.
+ This method is used by PathFinder.invalidate_caches().
+ """
+ return NotImplemented
+
_register(PathEntryFinder, machinery.FileFinder)
diff --git a/Lib/test/test_importlib/test_abc.py b/Lib/test/test_importlib/test_abc.py
--- a/Lib/test/test_importlib/test_abc.py
+++ b/Lib/test/test_importlib/test_abc.py
@@ -36,11 +36,13 @@
subclasses = [machinery.BuiltinImporter, machinery.FrozenImporter,
machinery.PathFinder, machinery.WindowsRegistryFinder]
+
class PathEntryFinder(InheritanceTests, unittest.TestCase):
superclasses = [abc.Finder]
subclasses = [machinery.FileFinder]
+
class Loader(InheritanceTests, unittest.TestCase):
subclasses = [abc.PyLoader]
diff --git a/Lib/test/test_importlib/test_api.py b/Lib/test/test_importlib/test_api.py
--- a/Lib/test/test_importlib/test_api.py
+++ b/Lib/test/test_importlib/test_api.py
@@ -148,11 +148,15 @@
self.called = True
key = 'gobledeegook'
- ins = InvalidatingNullFinder()
- sys.path_importer_cache[key] = ins
+ meta_ins = InvalidatingNullFinder()
+ path_ins = InvalidatingNullFinder()
+ sys.meta_path.insert(0, meta_ins)
self.addCleanup(lambda: sys.path_importer_cache.__delitem__(key))
+ sys.path_importer_cache[key] = path_ins
+ self.addCleanup(lambda: sys.meta_path.remove(meta_ins))
importlib.invalidate_caches()
- self.assertTrue(ins.called)
+ self.assertTrue(meta_ins.called)
+ self.assertTrue(path_ins.called)
def test_method_lacking(self):
# There should be no issues if the method is not defined.
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -80,6 +80,9 @@
Library
-------
+- Issue #15502: Have importlib.invalidate_caches() work on sys.meta_path
+ instead of sys.path_importer_cache.
+
- Issue #15163: Pydoc shouldn't list __loader__ as module data.
- Issue #15471: Do not use mutable objects as defaults for
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
More information about the Python-checkins
mailing list