[3.9] bpo-40924: Remove protocol for supplying Traversable objects from loaders (GH-20820)

Remove protocol that loaders can present a files method as found in importlib_resources 1.3-1.6 (added in Python 3.8b1).

Author: jaraco

Doc/library/importlib.rst

@@ -813,9 +813,6 @@ ABC hierarchy::
     methods. Therefore, any loader supplying TraversableReader
     also supplies ResourceReader.
 
-    Loaders that wish to support resource reading are expected to
-    implement this interface.
-
     .. versionadded:: 3.9
 
 

Lib/importlib/_common.py

@@ -11,17 +11,7 @@ def from_package(package):
     Return a Traversable object for the given package.
 
     """
-    spec = package.__spec__
-    return from_traversable_resources(spec) or fallback_resources(spec)
-
-
-def from_traversable_resources(spec):
-    """
-    If the spec.loader implements TraversableResources,
-    directly or implicitly, it will have a ``files()`` method.
-    """
-    with contextlib.suppress(AttributeError):
-        return spec.loader.files()
+    return fallback_resources(package.__spec__)
 
 
 def fallback_resources(spec):

Misc/NEWS.d/next/Library/2020-06-11-23-41-50.bpo-40924.m17Fkm.rst

@@ -0,0 +1 @@
+Removed support for loaders implementing .files and supplying TraversableResources.