gh-101438: Avoid reference cycle in ElementTree.iterparse.

Lib/xml/etree/ElementTree.py

@@ -99,6 +99,7 @@
 import collections
 import collections.abc
 import contextlib
+import weakref
 
 from . import ElementPath
 
@@ -1223,13 +1224,14 @@ def iterparse(source, events=None, parser=None):
  # parser argument of iterparse is removed, this can be killed.
  pullparser = XMLPullParser(events=events, _parser=parser)
 
- def iterator(source):
+ if not hasattr(source, "read"):
+ source = open(source, "rb")
+ close_source = True
+ else:
  close_source = False
+
+ def iterator(source):
  try:
- if not hasattr(source, "read"):
- source = open(source, "rb")
- close_source = True
- yield None
  while True:
  yield from pullparser.read_events()
  # load event buffer
@@ -1239,18 +1241,23 @@ def iterator(source):
  pullparser.feed(data)
  root = pullparser._close_and_return_root()
  yield from pullparser.read_events()
- it.root = root
+ it = wr()
+ if it is not None:
+ it.root = root
  finally:
  if close_source:
  source.close()
 
  class IterParseIterator(collections.abc.Iterator):
  __next__ = iterator(source).__next__
- it = IterParseIterator()
- it.root = None
- del iterator, IterParseIterator
 
- next(it)
+ def __del__(self):
+ if close_source:
+ source.close()
+
+ it = IterParseIterator()
+ wr = weakref.ref(it)
+ del IterParseIterator
  return it
 
 

Misc/NEWS.d/next/Library/2024-01-18-22-29-28.gh-issue-101438.1-uUi_.rst

@@ -0,0 +1,4 @@
+Avoid reference cycle in ElementTree.iterparse. The iterator returned by
+``ElementTree.iterparse`` may hold on to a file descriptor. The reference
+cycle prevented prompt clean-up of the file descriptor if the returned
+iterator was not exhausted.