gh-119584: Fix test_import Failed Assertion (gh-119623)

The fix in gh-119561 introduced an assertion that doesn't hold true if any of the three new test extension modules are loaded more than once.  This is fine normally but breaks if the new test_check_state_first() is run more than once, which happens for refleak checking and with the regrtest --forever flag.  We fix that here by clearing each of the three modules after loading them.  We also tweak a check in _modules_by_index_check().

diff --git a/Lib/test/test_import/__init__.py b/Lib/test/test_import/__init__.py
index 11eaae5e47e97ac21b2613abc9782946f12388a6..b09065f812c0e499b6f5070b309d129a7f8918bd 100644 (file)
--- a/Lib/test/test_import/__init__.py
+++ b/Lib/test/test_import/__init__.py
@@ -2887,12 +2887,15 @@ class SinglephaseInitTests(unittest.TestCase):
 
                 self.assertIs(reloaded.snapshot.cached, reloaded.module)
 
+    @unittest.skipIf(_testinternalcapi is None, "requires _testinternalcapi")
     def test_check_state_first(self):
         for variant in ['', '_with_reinit', '_with_state']:
             name = f'{self.NAME}{variant}_check_cache_first'
             with self.subTest(name):
                 mod = self._load_dynamic(name, self.ORIGIN)
                 self.assertEqual(mod.__name__, name)
+                sys.modules.pop(name, None)
+                _testinternalcapi.clear_extension(name, self.ORIGIN)
 
     # Currently, for every single-phrase init module loaded
     # in multiple interpreters, those interpreters share a

diff --git a/Modules/_testsinglephase.c b/Modules/_testsinglephase.c
index bcdb5ba31842fd7e5909910e083172b0a5db4a65..066e0dbfb63fbf4116ce3a849420581230aea584 100644 (file)
--- a/Modules/_testsinglephase.c
+++ b/Modules/_testsinglephase.c
@@ -682,6 +682,9 @@ finally:
 /* the _testsinglephase_*_check_cache_first modules */
 /****************************************************/
 
+/* Each of these modules should only be freshly loaded.  That means
+   clearing the caches and each module def's m_base after each load. */
+
 static struct PyModuleDef _testsinglephase_check_cache_first = {
     PyModuleDef_HEAD_INIT,
     .m_name = "_testsinglephase_check_cache_first",

diff --git a/Python/import.c b/Python/import.c
index 4f3325aa67bd0a5164ad1859f34e9c7ed1871371..6fe6df4db4f55eb06d626613e946e634af74155d 100644 (file)
--- a/Python/import.c
+++ b/Python/import.c
@@ -494,7 +494,7 @@ _modules_by_index_check(PyInterpreterState *interp, Py_ssize_t index)
     if (MODULES_BY_INDEX(interp) == NULL) {
         return "Interpreters module-list not accessible.";
     }
-    if (index > PyList_GET_SIZE(MODULES_BY_INDEX(interp))) {
+    if (index >= PyList_GET_SIZE(MODULES_BY_INDEX(interp))) {
         return "Module index out of bounds.";
     }
     return NULL;
@@ -2183,7 +2183,7 @@ clear_singlephase_extension(PyInterpreterState *interp,
     /* Clear data set when the module was initially loaded. */
     def->m_base.m_init = NULL;
     Py_CLEAR(def->m_base.m_copy);
-    // We leave m_index alone since there's no reason to reset it.
+    def->m_base.m_index = 0;
 
     /* Clear the PyState_*Module() cache entry. */
     Py_ssize_t index = _get_cached_module_index(cached);