bpo-29576: add explicit deprecation for importlib.abc.find_loader() and find_module() (GH-32)

Author: Carreau

Doc/whatsnew/3.7.rst

@@ -140,6 +140,17 @@ Deprecated
  ``0x03050400`` and ``0x03060000`` (not including) or ``0x03060100`` or
  higher. (Contributed by Serhiy Storchaka in :issue:`27867`.)
 
+- Methods
+ :meth:`MetaPathFinder.find_module() <importlib.abc.MetaPathFinder.find_module>`
+ (replaced by
+ :meth:`MetaPathFinder.find_spec() <importlib.abc.MetaPathFinder.find_spec>`
+ ) and
+ :meth:`PathEntryFinder.find_loader() <importlib.abc.PathEntryFinder.find_loader>`
+ (replaced by
+ :meth:`PathEntryFinder.find_spec() <importlib.abc.PathEntryFinder.find_spec>`)
+ both deprecated in Python 3.4 now emit :exc:`DeprecationWarning`. (Contributed
+ by Matthias Bussonnier in :issue:`29576`)
+
 
 Removed
 =======

Lib/importlib/__init__.py

@@ -79,7 +79,8 @@ def find_loader(name, path=None):
  This function is deprecated in favor of importlib.util.find_spec().
 
  """
- warnings.warn('Use importlib.util.find_spec() instead.',
+ warnings.warn('Deprecated since Python 3.4. '
+ 'Use importlib.util.find_spec() instead.',
  DeprecationWarning, stacklevel=2)
  try:
  loader = sys.modules[name].__loader__

Lib/importlib/abc.py

@@ -13,6 +13,7 @@
 except ImportError as exc:
  _frozen_importlib_external = _bootstrap_external
 import abc
+import warnings
 
 
 def _register(abstract_cls, *classes):
@@ -34,6 +35,8 @@ class Finder(metaclass=abc.ABCMeta):
  reimplementations of the import system. Otherwise, finder
  implementations should derive from the more specific MetaPathFinder
  or PathEntryFinder ABCs.
+
+ Deprecated since Python 3.3
  """
 
  @abc.abstractmethod
@@ -57,11 +60,16 @@ def find_module(self, fullname, path):
  If no module is found, return None. The fullname is a str and
  the path is a list of strings or None.
 
- This method is deprecated in favor of finder.find_spec(). If find_spec()
- exists then backwards-compatible functionality is provided for this
- method.
+ This method is deprecated since Python 3.4 in favor of
+ finder.find_spec(). If find_spec() exists then backwards-compatible
+ functionality is provided for this method.
 
  """
+ warnings.warn("MetaPathFinder.find_module() is deprecated since Python "
+ "3.4 in favor of MetaPathFinder.find_spec()"
+ "(available since 3.4)",
+ DeprecationWarning,
+ stacklevel=2)
  if not hasattr(self, 'find_spec'):
  return None
  found = self.find_spec(fullname, path)
@@ -94,10 +102,15 @@ def find_loader(self, fullname):
  The portion will be discarded if another path entry finder
  locates the module as a normal module or package.
 
- This method is deprecated in favor of finder.find_spec(). If find_spec()
- is provided than backwards-compatible functionality is provided.
-
+ This method is deprecated since Python 3.4 in favor of
+ finder.find_spec(). If find_spec() is provided than backwards-compatible
+ functionality is provided.
  """
+ warnings.warn("PathEntryFinder.find_loader() is deprecated since Python "
+ "3.4 in favor of PathEntryFinder.find_spec() "
+ "(available since 3.4)",
+ DeprecationWarning,
+ stacklevel=2)
  if not hasattr(self, 'find_spec'):
  return None, []
  found = self.find_spec(fullname)

Lib/test/test_importlib/test_abc.py

@@ -163,6 +163,9 @@ def test_invalidate_caches(self):
  # Calling the method is a no-op.
  self.ins.invalidate_caches()
 
+ def test_find_module_warns(self):
+ with self.assertWarns(DeprecationWarning):
+ self.ins.find_module('something', None)
 
 (Frozen_MPFDefaultTests,
  Source_MPFDefaultTests
@@ -189,6 +192,9 @@ def test_invalidate_caches(self):
  # Should be a no-op.
  self.ins.invalidate_caches()
 
+ def test_find_loader_warns(self):
+ with self.assertWarns(DeprecationWarning):
+ self.ins.find_loader('something')
 
 (Frozen_PEFDefaultTests,
  Source_PEFDefaultTests

Misc/NEWS

@@ -229,6 +229,9 @@ Extension Modules
 Library
 -------
 
+- bpo-29576: Improve some deprecations in importlib. Some deprecated methods
+ now emit DeprecationWarnings and have better descriptive messages.
+
 - bpo-29534: Fixed different behaviour of Decimal.from_float()
  for _decimal and _pydecimal. Thanks Andrew Nester.