gh-108308: Replace _PyDict_GetItemStringWithError()

Replace _PyDict_GetItemStringWithError() calls with
PyDict_GetItemStringRef() which returns a strong reference to the
item.

Author: vstinner

Objects/structseq.c

@@ -149,7 +149,6 @@ static PyObject *
 structseq_new_impl(PyTypeObject *type, PyObject *arg, PyObject *dict)
 /*[clinic end generated code: output=baa082e788b171da input=90532511101aa3fb]*/
 {
-    PyObject *ob;
     PyStructSequence *res = NULL;
     Py_ssize_t len, min_len, max_len, i, n_unnamed_fields;
 
@@ -219,21 +218,21 @@ structseq_new_impl(PyTypeObject *type, PyObject *arg, PyObject *dict)
     }
     Py_DECREF(arg);
     for (; i < max_len; ++i) {
+        PyObject *ob;
         if (dict == NULL) {
-            ob = Py_None;
+            ob = Py_NewRef(Py_None);
         }
         else {
-            ob = _PyDict_GetItemStringWithError(dict,
-                type->tp_members[i-n_unnamed_fields].name);
+            const char *name = type->tp_members[i-n_unnamed_fields].name;
+            if (PyDict_GetItemStringRef(dict, name, &ob) < 0) {
+                Py_DECREF(res);
+                return NULL;
+            }
             if (ob == NULL) {
-                if (PyErr_Occurred()) {
-                    Py_DECREF(res);
-                    return NULL;
-                }
-                ob = Py_None;
+                ob = Py_NewRef(Py_None);
             }
         }
-        res->ob_item[i] = Py_NewRef(ob);
+        res->ob_item[i] = ob;
     }
 
     _PyObject_GC_TRACK(res);

Python/codecs.c

@@ -618,20 +618,19 @@ int PyCodec_RegisterError(const char *name, PyObject *error)
    the error handling callback for strict encoding will be returned. */
 PyObject *PyCodec_LookupError(const char *name)
 {
-    PyObject *handler = NULL;
-
     PyInterpreterState *interp = _PyInterpreterState_GET();
     if (interp->codec_search_path == NULL && _PyCodecRegistry_Init())
         return NULL;
 
     if (name==NULL)
         name = "strict";
-    handler = _PyDict_GetItemStringWithError(interp->codec_error_registry, name);
-    if (handler) {
-        Py_INCREF(handler);
+    PyObject *handler;
+    if (PyDict_GetItemStringRef(interp->codec_error_registry, name, &handler) < 0) {
+        return NULL;
     }
-    else if (!PyErr_Occurred()) {
+    if (handler == NULL) {
         PyErr_Format(PyExc_LookupError, "unknown error handler name '%.400s'", name);
+        return NULL;
     }
     return handler;
 }

Python/import.c

@@ -2435,12 +2435,11 @@ int
 _PyImport_InitDefaultImportFunc(PyInterpreterState *interp)
 {
     // Get the __import__ function
-    PyObject *import_func = _PyDict_GetItemStringWithError(interp->builtins,
-                                                           "__import__");
-    if (import_func == NULL) {
+    PyObject *import_func;
+    if (PyDict_GetItemStringRef(interp->builtins, "__import__", &import_func) <= 0) {
         return -1;
     }
-    IMPORT_FUNC(interp) = Py_NewRef(import_func);
+    IMPORT_FUNC(interp) = import_func;
     return 0;
 }
 

Python/pylifecycle.c

@@ -1372,17 +1372,17 @@ finalize_modules_delete_special(PyThreadState *tstate, int verbose)
         if (verbose) {
             PySys_WriteStderr("# restore sys.%s\n", name);
         }
-        PyObject *value = _PyDict_GetItemStringWithError(interp->sysdict,
-                                                         orig_name);
-        if (value == NULL) {
-            if (_PyErr_Occurred(tstate)) {
-                PyErr_WriteUnraisable(NULL);
-            }
-            value = Py_None;
+        PyObject *value;
+        if (PyDict_GetItemStringRef(interp->sysdict, orig_name, &value) < 0) {
+            PyErr_WriteUnraisable(NULL);
+            value = Py_NewRef(Py_None);
+        } else if (value == NULL) {
+            value = Py_NewRef(Py_None);
         }
         if (PyDict_SetItemString(interp->sysdict, name, value) < 0) {
             PyErr_WriteUnraisable(NULL);
         }
+        Py_DECREF(value);
     }
 }
 
@@ -2207,7 +2207,7 @@ _Py_IsInterpreterFinalizing(PyInterpreterState *interp)
 static PyStatus
 add_main_module(PyInterpreterState *interp)
 {
-    PyObject *m, *d, *loader, *ann_dict;
+    PyObject *m, *d, *ann_dict;
     m = PyImport_AddModule("__main__");
     if (m == NULL)
         return _PyStatus_ERR("can't create __main__ module");
@@ -2220,10 +2220,13 @@ add_main_module(PyInterpreterState *interp)
     }
     Py_DECREF(ann_dict);
 
-    if (_PyDict_GetItemStringWithError(d, "__builtins__") == NULL) {
-        if (PyErr_Occurred()) {
-            return _PyStatus_ERR("Failed to test __main__.__builtins__");
-        }
+    PyObject *builtins;
+    if (PyDict_GetItemStringRef(d, "__builtins__", &builtins) < 0) {
+        return _PyStatus_ERR("Failed to test __main__.__builtins__");
+    }
+    int has_buitlins = (builtins != NULL);
+    Py_XDECREF(builtins);
+    if (!has_buitlins) {
         PyObject *bimod = PyImport_ImportModule("builtins");
         if (bimod == NULL) {
             return _PyStatus_ERR("Failed to retrieve builtins module");
@@ -2239,11 +2242,13 @@ add_main_module(PyInterpreterState *interp)
      * will be set if __main__ gets further initialized later in the startup
      * process.
      */
-    loader = _PyDict_GetItemStringWithError(d, "__loader__");
-    if (loader == NULL || loader == Py_None) {
-        if (PyErr_Occurred()) {
-            return _PyStatus_ERR("Failed to test __main__.__loader__");
-        }
+    PyObject *loader;
+    if (PyDict_GetItemStringRef(d, "__loader__", &loader) < 0) {
+        return _PyStatus_ERR("Failed to test __main__.__loader__");
+    }
+    int has_loader = !(loader == NULL || loader == Py_None);
+    Py_XDECREF(loader);
+    if (!has_loader) {
         PyObject *loader = _PyImport_GetImportlibLoader(interp,
                                                         "BuiltinImporter");
         if (loader == NULL) {