bpo-41490: ``path`` and ``contents`` to aggressively close handles (#22915)

* bpo-41490: ``path`` method to aggressively close handles

* Add blurb

* In ZipReader.contents, eagerly evaluate the contents to release references to the zipfile.

* Instead use _ensure_sequence to ensure any iterable from a reader is eagerly converted to a list if it's not already a sequence.

1 files changed, 2 insertions, 3 deletions

diff --git a/Lib/importlib/_common.py b/Lib/importlib/_common.py
index b15c59eb9c..71ce6af8cc 100644
--- a/Lib/importlib/_common.py
+++ b/Lib/importlib/_common.py
@@ -88,6 +88,7 @@ def _tempfile(reader, suffix=''):
     try:
         os.write(fd, reader())
         os.close(fd)
+        del reader
         yield pathlib.Path(raw_path)
     finally:
         try:
@@ -97,14 +98,12 @@ def _tempfile(reader, suffix=''):
 
 
 @functools.singledispatch
-@contextlib.contextmanager
 def as_file(path):
     """
     Given a Traversable object, return that object as a
     path on the local file system in a context manager.
     """
-    with _tempfile(path.read_bytes, suffix=path.name) as local:
-        yield local
+    return _tempfile(path.read_bytes, suffix=path.name)
 
 
 @as_file.register(pathlib.Path)