gh-81954: Eagerly import warnings module to failure of ZipFile.__del__ during finalization

Lib/test/test_zipfile/test_core.py

@@ -26,7 +26,7 @@
 from test.support import (
     findfile, requires_zlib, requires_bz2, requires_lzma,
     requires_zstd, captured_stdout, captured_stderr, requires_subprocess,
-    cpython_only, gc_collect
+    cpython_only, gc_collect, catch_unraisable_exception
 )
 from test.support.os_helper import (
     TESTFN, unlink, rmtree, temp_dir, temp_cwd, fd_count, FakePath,
@@ -4095,6 +4095,14 @@ def test_garbage_collection(self):
             zf.close()
             del zf
 
+        # ResourceWarning escalated to an error is reported as unraisable.
+        zf = zipfile.ZipFile(io.BytesIO(), "w")
+        with (warnings.catch_warnings(action="error", category=ResourceWarning),
+              catch_unraisable_exception() as cm):
+            del zf
+            gc_collect()
+            self.assertIs(cm.unraisable.exc_type, ResourceWarning)
+
     def test_unsupported_version(self):
         # File has an extract_version of 120
         data = (b'PK\x03\x04x\x00\x00\x00\x00\x00!p\xa1@\x00\x00\x00\x00\x00\x00'

Lib/zipfile/__init__.py

@@ -12,7 +12,7 @@
 import sys
 import threading
 import time
-lazy import warnings
+import warnings  # must stay eager to support finalization
 
 try:
     import zlib # We may need its compression method

Misc/NEWS.d/next/Library/2026-10-14-14-47-05.gh-issue-81954.KvM0gY.rst

@@ -0,0 +1,4 @@
+:mod:`zipfile` now imports :mod:`warnings` eagerly so that a writable
+:class:`~zipfile.ZipFile` left unclosed at interpreter shutdown can emit its
+:exc:`ResourceWarning` and be closed instead of failing with an
+:exc:`ImportError`.