gh-105927: Avoid calling PyWeakref_GET_OBJECT() (#105997)

* Replace PyWeakref_GET_OBJECT() with _PyWeakref_GET_REF().
* _sqlite/blob.c now holds a strong reference to the blob object
  while calling close_blob().
* _xidregistry_find_type() now holds a strong reference to registered
  while using it.

Author: vstinner

Modules/_sqlite/blob.c

@@ -1,5 +1,10 @@
+#ifndef Py_BUILD_CORE_BUILTIN
+#  define Py_BUILD_CORE_MODULE 1
+#endif
+
 #include "blob.h"
 #include "util.h"
+#include "pycore_weakref.h"       // _PyWeakref_GET_REF()
 
 #define clinic_state() (pysqlite_get_state_by_type(Py_TYPE(self)))
 #include "clinic/blob.c.h"
@@ -97,10 +102,12 @@ pysqlite_close_all_blobs(pysqlite_Connection *self)
 {
     for (int i = 0; i < PyList_GET_SIZE(self->blobs); i++) {
         PyObject *weakref = PyList_GET_ITEM(self->blobs, i);
-        PyObject *blob = PyWeakref_GetObject(weakref);
-        if (!Py_IsNone(blob)) {
-            close_blob((pysqlite_Blob *)blob);
+        PyObject *blob = _PyWeakref_GET_REF(weakref);
+        if (blob == NULL) {
+            continue;
         }
+        close_blob((pysqlite_Blob *)blob);
+        Py_DECREF(blob);
     }
 }
 

Objects/weakrefobject.c

@@ -140,7 +140,11 @@ weakref_vectorcall(PyObject *self, PyObject *const *args,
     if (!_PyArg_CheckPositional("weakref", nargs, 0, 0)) {
         return NULL;
     }
-    return Py_NewRef(PyWeakref_GET_OBJECT(self));
+    PyObject *obj = _PyWeakref_GET_REF(self);
+    if (obj == NULL) {
+        Py_RETURN_NONE;
+    }
+    return obj;
 }
 
 static Py_hash_t

Python/pystate.c

@@ -13,7 +13,8 @@
 #include "pycore_pymem.h"         // _PyMem_SetDefaultAllocator()
 #include "pycore_pystate.h"
 #include "pycore_runtime_init.h"  // _PyRuntimeState_INIT
-#include "pycore_sysmodule.h"
+#include "pycore_sysmodule.h"     // _PySys_Audit()
+#include "pycore_weakref.h"       // _PyWeakref_GET_REF()
 
 /* --------------------------------------------------------------------------
 CAUTION
@@ -2589,16 +2590,18 @@ _xidregistry_find_type(struct _xidregistry *xidregistry, PyTypeObject *cls)
 {
     struct _xidregitem *cur = xidregistry->head;
     while (cur != NULL) {
-        PyObject *registered = PyWeakref_GetObject(cur->cls);
-        if (registered == Py_None) {
+        PyObject *registered = _PyWeakref_GET_REF(cur->cls);
+        if (registered == NULL) {
             // The weakly ref'ed object was freed.
             cur = _xidregistry_remove_entry(xidregistry, cur);
         }
         else {
             assert(PyType_Check(registered));
             if (registered == (PyObject *)cls) {
+                Py_DECREF(registered);
                 return cur;
             }
+            Py_DECREF(registered);
             cur = cur->next;
         }
     }