Replace few new occurrences of PySys_GetObject().

Author: serhiy-storchaka

Objects/moduleobject.c

@@ -1001,13 +1001,18 @@ _Py_module_getattro_impl(PyModuleObject *m, PyObject *name, int suppress)
     }
     int is_possibly_shadowing_stdlib = 0;
     if (is_possibly_shadowing) {
-        PyObject *stdlib_modules = PySys_GetObject("stdlib_module_names");
+        PyObject *stdlib_modules;
+        if (PySys_GetOptionalAttrString("stdlib_module_names", &stdlib_modules) < 0) {
+            goto done;
+        }
         if (stdlib_modules && PyAnySet_Check(stdlib_modules)) {
             is_possibly_shadowing_stdlib = PySet_Contains(stdlib_modules, mod_name);
             if (is_possibly_shadowing_stdlib < 0) {
+                Py_DECREF(stdlib_modules);
                 goto done;
             }
         }
+        Py_XDECREF(stdlib_modules);
     }
 
     if (is_possibly_shadowing_stdlib) {

Python/ceval.c

@@ -2765,13 +2765,18 @@ _PyEval_ImportFrom(PyThreadState *tstate, PyObject *v, PyObject *name)
     }
     int is_possibly_shadowing_stdlib = 0;
     if (is_possibly_shadowing) {
-        PyObject *stdlib_modules = PySys_GetObject("stdlib_module_names");
+        PyObject *stdlib_modules;
+        if (PySys_GetOptionalAttrString("stdlib_module_names", &stdlib_modules) < 0) {
+            goto done;
+        }
         if (stdlib_modules && PyAnySet_Check(stdlib_modules)) {
             is_possibly_shadowing_stdlib = PySet_Contains(stdlib_modules, mod_name_or_unknown);
             if (is_possibly_shadowing_stdlib < 0) {
+                Py_DECREF(stdlib_modules);
                 goto done;
             }
         }
+        Py_XDECREF(stdlib_modules);
     }
 
     if (origin == NULL && PyModule_Check(v)) {

Python/initconfig.c

@@ -4091,22 +4091,10 @@ _PyConfig_CreateXOptionsDict(const PyConfig *config)
 }
 
 
-static PyObject*
-config_get_sys(const char *name)
-{
-    PyObject *value = PySys_GetObject(name);
-    if (value == NULL) {
-        PyErr_Format(PyExc_RuntimeError, "lost sys.%s", name);
-        return NULL;
-    }
-    return Py_NewRef(value);
-}
-
-
 static int
 config_get_sys_write_bytecode(const PyConfig *config, int *value)
 {
-    PyObject *attr = config_get_sys("dont_write_bytecode");
+    PyObject *attr = PySys_GetAttrString("dont_write_bytecode");
     if (attr == NULL) {
         return -1;
     }
@@ -4127,7 +4115,7 @@ config_get(const PyConfig *config, const PyConfigSpec *spec,
 {
     if (use_sys) {
         if (spec->sys.attr != NULL) {
-            return config_get_sys(spec->sys.attr);
+            return PySys_GetAttrString(spec->sys.attr);
         }
 
         if (strcmp(spec->name, "write_bytecode") == 0) {

Python/sysmodule.c

@@ -3230,11 +3230,8 @@ sys_set_flag(PyObject *flags, Py_ssize_t pos, PyObject *value)
 int
 _PySys_SetFlagObj(Py_ssize_t pos, PyObject *value)
 {
-    PyObject *flags = Py_XNewRef(PySys_GetObject("flags"));
+    PyObject *flags = PySys_GetAttrString("flags");
     if (flags == NULL) {
-        if (!PyErr_Occurred()) {
-            PyErr_SetString(PyExc_RuntimeError, "lost sys.flags");
-        }
         return -1;
     }