bpo-33254: do not return an empty list when asking for the contents of a namespace package (GH-6467)
diff --git a/Doc/library/importlib.rst b/Doc/library/importlib.rst
index 130aabf..e33abae 100644
--- a/Doc/library/importlib.rst
+++ b/Doc/library/importlib.rst
@@ -530,7 +530,7 @@
.. abstractmethod:: contents()
- Returns an :term:`iterator` of strings over the contents of
+ Returns an :term:`iterable` of strings over the contents of
the package. Do note that it is not required that all names
returned by the iterator be actual resources, e.g. it is
acceptable to return names for which :meth:`is_resource` would
@@ -544,7 +544,7 @@
the file system then those subdirectory names can be used
directly.
- The abstract method returns an iterator of no items.
+ The abstract method returns an iterable of no items.
.. class:: ResourceLoader
@@ -926,9 +926,9 @@
.. function:: contents(package)
- Return an iterator over the named items within the package. The iterator
+ Return an iterable over the named items within the package. The iterable
returns :class:`str` resources (e.g. files) and non-resources
- (e.g. directories). The iterator does not recurse into subdirectories.
+ (e.g. directories). The iterable does not recurse into subdirectories.
*package* is either a name or a module object which conforms to the
``Package`` requirements.
diff --git a/Lib/importlib/abc.py b/Lib/importlib/abc.py
index d2f4509..dbdd5bf 100644
--- a/Lib/importlib/abc.py
+++ b/Lib/importlib/abc.py
@@ -381,8 +381,8 @@
@abc.abstractmethod
def contents(self):
- """Return an iterator of strings over the contents of the package."""
- return iter([])
+ """Return an iterable of strings over the contents of the package."""
+ return []
_register(ResourceReader, machinery.SourceFileLoader)
diff --git a/Lib/importlib/resources.py b/Lib/importlib/resources.py
index e565427..4d70186 100644
--- a/Lib/importlib/resources.py
+++ b/Lib/importlib/resources.py
@@ -9,7 +9,7 @@
from io import BytesIO, TextIOWrapper
from pathlib import Path
from types import ModuleType
-from typing import Iterator, Optional, Set, Union # noqa: F401
+from typing import Iterable, Iterator, Optional, Set, Union # noqa: F401
from typing import cast
from typing.io import BinaryIO, TextIO
from zipimport import ZipImportError
@@ -44,8 +44,7 @@
If the resulting string contains path separators, an exception is raised.
"""
- str_path = str(path)
- parent, file_name = os.path.split(str_path)
+ parent, file_name = os.path.split(path)
if parent:
raise ValueError('{!r} must be only a file name'.format(path))
else:
@@ -228,8 +227,8 @@
return path.is_file()
-def contents(package: Package) -> Iterator[str]:
- """Return the list of entries in 'package'.
+def contents(package: Package) -> Iterable[str]:
+ """Return an iterable of entries in 'package'.
Note that not all entries are resources. Specifically, directories are
not considered resources. Use `is_resource()` on each entry returned here
@@ -238,15 +237,15 @@
package = _get_package(package)
reader = _get_resource_reader(package)
if reader is not None:
- yield from reader.contents()
- return
+ return reader.contents()
# Is the package a namespace package? By definition, namespace packages
# cannot have resources. We could use _check_location() and catch the
# exception, but that's extra work, so just inline the check.
- if package.__spec__.origin is None or not package.__spec__.has_location:
- return []
- package_directory = Path(package.__spec__.origin).parent
- yield from os.listdir(str(package_directory))
+ elif package.__spec__.origin is None or not package.__spec__.has_location:
+ return ()
+ else:
+ package_directory = Path(package.__spec__.origin).parent
+ return os.listdir(package_directory)
# Private implementation of ResourceReader and get_resource_reader() for
diff --git a/Lib/test/test_importlib/test_resource.py b/Lib/test/test_importlib/test_resource.py
index d717e1d..b076860 100644
--- a/Lib/test/test_importlib/test_resource.py
+++ b/Lib/test/test_importlib/test_resource.py
@@ -131,10 +131,9 @@
class NamespaceTest(unittest.TestCase):
- def test_namespaces_cant_have_resources(self):
- contents = set(resources.contents(
- 'test.test_importlib.data03.namespace'))
- self.assertEqual(len(contents), 0)
+ def test_namespaces_cannot_have_resources(self):
+ contents = resources.contents('test.test_importlib.data03.namespace')
+ self.assertFalse(list(contents))
# Even though there is a file in the namespace directory, it is not
# considered a resource, since namespace packages can't have them.
self.assertFalse(resources.is_resource(
diff --git a/Misc/NEWS.d/next/Library/2018-04-13-15-14-47.bpo-33254.DS4KFK.rst b/Misc/NEWS.d/next/Library/2018-04-13-15-14-47.bpo-33254.DS4KFK.rst
new file mode 100644
index 0000000..c77a902
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-04-13-15-14-47.bpo-33254.DS4KFK.rst
@@ -0,0 +1,3 @@
+Have :func:`importlib.resources.contents` and
+:meth:`importlib.abc.ResourceReader.contents` return an :term:`iterable` instead
+of an :term:`iterator`.