bpo-30860: Fix a refleak. (#3506)

* Drop warnoptions from PyInterpreterState.

* Drop xoptions from PyInterpreterState.

* Don't set warnoptions and _xoptions again.

* Decref after adding to sys.__dict__.

* Drop an unused macro.

* Check sys.xoptions *before* we delete it.

Include/object.h

@@ -727,14 +727,13 @@ PyAPI_FUNC(Py_ssize_t) _Py_GetRefTotal(void);
 /* Py_REF_DEBUG also controls the display of refcounts and memory block
  * allocations at the interactive prompt and at interpreter shutdown
  */
+PyAPI_FUNC(PyObject *) _PyDebug_XOptionShowRefCount(void);
 PyAPI_FUNC(void) _PyDebug_PrintTotalRefs(void);
-#define _PY_DEBUG_PRINT_TOTAL_REFS() _PyDebug_PrintTotalRefs()
 #else
 #define _Py_INC_REFTOTAL
 #define _Py_DEC_REFTOTAL
 #define _Py_REF_DEBUG_COMMA
 #define _Py_CHECK_REFCNT(OP)    /* a semicolon */;
-#define _PY_DEBUG_PRINT_TOTAL_REFS()
 #endif /* Py_REF_DEBUG */
 
 #ifdef COUNT_ALLOCS

Include/pystate.h

@@ -60,8 +60,6 @@ typedef struct _is {
 
     /* Used in Python/sysmodule.c. */
     int check_interval;
-    PyObject *warnoptions;
-    PyObject *xoptions;
 
     /* Used in Modules/_threadmodule.c. */
     long num_threads;

Objects/object.c

@@ -29,20 +29,23 @@ _Py_GetRefTotal(void)
     return total;
 }
 
-void
-_PyDebug_PrintTotalRefs(void) {
-    PyObject *xoptions, *value;
+PyObject *
+_PyDebug_XOptionShowRefCount(void)
+{
+    PyObject *xoptions = PySys_GetXOptions();
+    if (xoptions == NULL)
+        return NULL;
+
     _Py_IDENTIFIER(showrefcount);
+    return _PyDict_GetItemId(xoptions, &PyId_showrefcount);
+}
 
-    xoptions = PySys_GetXOptions();
-    if (xoptions == NULL)
-        return;
-    value = _PyDict_GetItemId(xoptions, &PyId_showrefcount);
-    if (value == Py_True)
-        fprintf(stderr,
-                "[%" PY_FORMAT_SIZE_T "d refs, "
-                "%" PY_FORMAT_SIZE_T "d blocks]\n",
-                _Py_GetRefTotal(), _Py_GetAllocatedBlocks());
+void
+_PyDebug_PrintTotalRefs(void) {
+    fprintf(stderr,
+            "[%" PY_FORMAT_SIZE_T "d refs, "
+            "%" PY_FORMAT_SIZE_T "d blocks]\n",
+            _Py_GetRefTotal(), _Py_GetAllocatedBlocks());
 }
 #endif /* Py_REF_DEBUG */
 

Python/pylifecycle.c

@@ -1006,6 +1006,11 @@ Py_FinalizeEx(void)
     while (_PyGC_CollectIfEnabled() > 0)
         /* nothing */;
 #endif
+
+#ifdef Py_REF_DEBUG
+    PyObject *showrefcount = _PyDebug_XOptionShowRefCount();
+#endif
+
     /* Destroy all modules */
     PyImport_Cleanup();
 
@@ -1053,7 +1058,10 @@ Py_FinalizeEx(void)
     /* dump hash stats */
     _PyHash_Fini();
 
-    _PY_DEBUG_PRINT_TOTAL_REFS();
+#ifdef Py_REF_DEBUG
+        if (showrefcount == Py_True)
+            _PyDebug_PrintTotalRefs();
+#endif
 
 #ifdef Py_TRACE_REFS
     /* Display all objects still alive -- this can invoke arbitrary

Python/pystate.c

@@ -96,8 +96,6 @@ PyInterpreterState_New(void)
         interp->builtins_copy = NULL;
         interp->tstate_head = NULL;
         interp->check_interval = 100;
-        interp->warnoptions = NULL;
-        interp->xoptions = NULL;
         interp->num_threads = 0;
         interp->pythread_stacksize = 0;
         interp->codec_search_path = NULL;

Python/pythonrun.c

@@ -113,7 +113,10 @@ PyRun_InteractiveLoopFlags(FILE *fp, const char *filename_str, PyCompilerFlags *
     err = -1;
     for (;;) {
         ret = PyRun_InteractiveOneObject(fp, filename, flags);
-        _PY_DEBUG_PRINT_TOTAL_REFS();
+#ifdef Py_REF_DEBUG
+        if (_PyDebug_XOptionShowRefCount() == Py_True)
+            _PyDebug_PrintTotalRefs();
+#endif
         if (ret == E_EOF) {
             err = 0;
             break;

Python/sysmodule.c

@@ -36,12 +36,14 @@ extern const char *PyWin_DLLVersionString;
 
 _Py_IDENTIFIER(_);
 _Py_IDENTIFIER(__sizeof__);
+_Py_IDENTIFIER(_xoptions);
 _Py_IDENTIFIER(buffer);
 _Py_IDENTIFIER(builtins);
 _Py_IDENTIFIER(encoding);
 _Py_IDENTIFIER(path);
 _Py_IDENTIFIER(stdout);
 _Py_IDENTIFIER(stderr);
+_Py_IDENTIFIER(warnoptions);
 _Py_IDENTIFIER(write);
 
 PyObject *
@@ -1479,13 +1481,17 @@ list_builtin_module_names(void)
 static PyObject *
 get_warnoptions(void)
 {
-    PyObject *warnoptions = PyThreadState_GET()->interp->warnoptions;
+    PyObject *warnoptions = _PySys_GetObjectId(&PyId_warnoptions);
     if (warnoptions == NULL || !PyList_Check(warnoptions)) {
         Py_XDECREF(warnoptions);
         warnoptions = PyList_New(0);
         if (warnoptions == NULL)
             return NULL;
-        PyThreadState_GET()->interp->warnoptions = warnoptions;
+        if (_PySys_SetObjectId(&PyId_warnoptions, warnoptions)) {
+            Py_DECREF(warnoptions);
+            return NULL;
+        }
+        Py_DECREF(warnoptions);
     }
     return warnoptions;
 }
@@ -1493,7 +1499,7 @@ get_warnoptions(void)
 void
 PySys_ResetWarnOptions(void)
 {
-    PyObject *warnoptions = PyThreadState_GET()->interp->warnoptions;
+    PyObject *warnoptions = _PySys_GetObjectId(&PyId_warnoptions);
     if (warnoptions == NULL || !PyList_Check(warnoptions))
         return;
     PyList_SetSlice(warnoptions, 0, PyList_GET_SIZE(warnoptions), NULL);
@@ -1522,20 +1528,24 @@ PySys_AddWarnOption(const wchar_t *s)
 int
 PySys_HasWarnOptions(void)
 {
-    PyObject *warnoptions = PyThreadState_GET()->interp->warnoptions;
+    PyObject *warnoptions = _PySys_GetObjectId(&PyId_warnoptions);
     return (warnoptions != NULL && (PyList_Size(warnoptions) > 0)) ? 1 : 0;
 }
 
 static PyObject *
 get_xoptions(void)
 {
-    PyObject *xoptions = PyThreadState_GET()->interp->xoptions;
+    PyObject *xoptions = _PySys_GetObjectId(&PyId__xoptions);
     if (xoptions == NULL || !PyDict_Check(xoptions)) {
         Py_XDECREF(xoptions);
         xoptions = PyDict_New();
         if (xoptions == NULL)
             return NULL;
-        PyThreadState_GET()->interp->xoptions = xoptions;
+        if (_PySys_SetObjectId(&PyId__xoptions, xoptions)) {
+            Py_DECREF(xoptions);
+            return NULL;
+        }
+        Py_DECREF(xoptions);
     }
     return xoptions;
 }
@@ -2084,16 +2094,6 @@ _PySys_BeginInit(void)
 #undef SET_SYS_FROM_STRING_BORROW
 
 /* Updating the sys namespace, returning integer error codes */
-#define SET_SYS_FROM_STRING_BORROW_INT_RESULT(key, value)  \
-    do {                                                   \
-        PyObject *v = (value);                             \
-        if (v == NULL)                                     \
-            return -1;                                     \
-        res = PyDict_SetItemString(sysdict, key, v);       \
-        if (res < 0) {                                     \
-            return res;                                    \
-        }                                                  \
-    } while (0)
 #define SET_SYS_FROM_STRING_INT_RESULT(key, value)         \
     do {                                                   \
         PyObject *v = (value);                             \
@@ -2138,15 +2138,11 @@ _PySys_EndInit(PyObject *sysdict)
     SET_SYS_FROM_STRING_INT_RESULT("base_exec_prefix",
                         PyUnicode_FromWideChar(Py_GetExecPrefix(), -1));
 
-    PyObject *warnoptions = get_warnoptions();
-    if (warnoptions == NULL)
+    if (get_warnoptions() == NULL)
         return -1;
-    SET_SYS_FROM_STRING_BORROW_INT_RESULT("warnoptions", warnoptions);
 
-    PyObject *xoptions = get_xoptions();
-    if (xoptions == NULL)
+    if (get_xoptions() == NULL)
         return -1;
-    SET_SYS_FROM_STRING_BORROW_INT_RESULT("_xoptions", xoptions);
 
     if (PyErr_Occurred())
         return -1;
@@ -2154,7 +2150,6 @@ _PySys_EndInit(PyObject *sysdict)
 }
 
 #undef SET_SYS_FROM_STRING_INT_RESULT
-#undef SET_SYS_FROM_STRING_BORROW_INT_RESULT
 
 static PyObject *
 makepathobject(const wchar_t *path, wchar_t delim)