gh-150633: Properly handle null characters in the name when importing frozen modules...

diff --git a/Lib/test/test_import/__init__.py b/Lib/test/test_import/__init__.py
index c905c0da0a12327faf1a5f5ca12f884af9efbd5a..f8e77fc7c532c4ba2b0313a74a5f2c6094e08899 100644 (file)
--- a/Lib/test/test_import/__init__.py
+++ b/Lib/test/test_import/__init__.py
@@ -364,6 +364,15 @@ class ImportTests(unittest.TestCase):
         with self.assertRaises(ModuleNotFoundError):
             import something_that_should_not_exist_anywhere
 
+    def test_import_null_byte_in_name_raises_ModuleNotFoundError(self):
+        # gh-150633: module names containing null bytes should not
+        # lead to duplicates in sys.modules
+        before = set(sys.modules.keys())
+        with self.assertRaises(ModuleNotFoundError):
+            __import__('zipimport\x00junk')
+
+        self.assertEqual(set(sys.modules.keys()), before)
+
     def test_from_import_missing_module_raises_ModuleNotFoundError(self):
         with self.assertRaises(ModuleNotFoundError):
             from something_that_should_not_exist_anywhere import blah

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-05-30-20-19-35.gh-issue-150633.XkNul0.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-05-30-20-19-35.gh-issue-150633.XkNul0.rst
new file mode 100644 (file)
index 0000000..c397ad6
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-05-30-20-19-35.gh-issue-150633.XkNul0.rst
@@ -0,0 +1,3 @@
+Fix the frozen importer accepting module names with embedded null bytes, which
+caused it to bypass the :data:`sys.modules` cache and create duplicate module
+objects.

diff --git a/Python/import.c b/Python/import.c
index 82d15ad0683c190d32aba5e9410c1349751a2308..42bfe15121f84f78f1243e21573fedcf9da15ab7 100644 (file)
--- a/Python/import.c
+++ b/Python/import.c
@@ -3174,7 +3174,7 @@ find_frozen(PyObject *nameobj, struct frozen_info *info)
     if (nameobj == NULL || nameobj == Py_None) {
         return FROZEN_BAD_NAME;
     }
-    const char *name = PyUnicode_AsUTF8(nameobj);
+    const char *name = _PyUnicode_AsUTF8NoNUL(nameobj);
     if (name == NULL) {
         // Note that this function previously used
         // _PyUnicode_EqualToASCIIString().  We clear the error here