[3.12] gh-117084: Fix ZIP file extraction for directory entry names with backslashes on Windows (GH-117129) (GH-117162)

(cherry picked from commit 567ab3bd15398c8c7b791f3e376ae3e3c0bbe079)

2 files changed, 16 insertions, 0 deletions

diff --git a/Lib/test/test_zipfile/test_core.py b/Lib/test/test_zipfile/test_core.py
index ae58145..5b32f80 100644
--- a/Lib/test/test_zipfile/test_core.py
+++ b/Lib/test/test_zipfile/test_core.py
@@ -2937,6 +2937,22 @@ class TestWithDirectory(unittest.TestCase):
         os.mkdir(os.path.join(TESTFN2, "a"))
         self.test_extract_dir()
 
+    def test_extract_dir_backslash(self):
+        zfname = findfile("zipdir_backslash.zip")
+        with zipfile.ZipFile(zfname) as zipf:
+            zipf.extractall(TESTFN2)
+        if os.name == 'nt':
+            self.assertTrue(os.path.isdir(os.path.join(TESTFN2, "a")))
+            self.assertTrue(os.path.isdir(os.path.join(TESTFN2, "a", "b")))
+            self.assertTrue(os.path.isfile(os.path.join(TESTFN2, "a", "b", "c")))
+            self.assertTrue(os.path.isdir(os.path.join(TESTFN2, "d")))
+            self.assertTrue(os.path.isdir(os.path.join(TESTFN2, "d", "e")))
+        else:
+            self.assertTrue(os.path.isfile(os.path.join(TESTFN2, "a\\b\\c")))
+            self.assertTrue(os.path.isfile(os.path.join(TESTFN2, "d\\e\\")))
+            self.assertFalse(os.path.exists(os.path.join(TESTFN2, "a")))
+            self.assertFalse(os.path.exists(os.path.join(TESTFN2, "d")))
+
     def test_write_dir(self):
         dirpath = os.path.join(TESTFN2, "x")
         os.mkdir(dirpath)
diff --git a/Lib/test/zipdir_backslash.zip b/Lib/test/zipdir_backslash.zip
new file mode 100644
index 0000000..979126e
--- /dev/null
+++ b/Lib/test/zipdir_backslash.zip