[3.14] gh-146092: Fix error handling in _BINARY_OP_ADD_FLOAT opcode

Misc/NEWS.d/next/Core_and_Builtins/2026-03-18-16-57-56.gh-issue-146092.wCKFYS.rst

@@ -0,0 +1,2 @@
+Handle properly memory allocation failures on str and float opcodes. Patch by
+Victor Stinner.

Objects/floatobject.c

@@ -139,7 +139,11 @@ _PyStackRef _PyFloat_FromDouble_ConsumeInputs(_PyStackRef left, _PyStackRef righ
 {
     PyStackRef_CLOSE_SPECIALIZED(left, _PyFloat_ExactDealloc);
     PyStackRef_CLOSE_SPECIALIZED(right, _PyFloat_ExactDealloc);
-    return PyStackRef_FromPyObjectSteal(PyFloat_FromDouble(value));
+    PyObject *obj = PyFloat_FromDouble(value);
+    if (obj == NULL) {
+        return PyStackRef_NULL;
+    }
+    return PyStackRef_FromPyObjectSteal(obj);
 }
 
 static PyObject *

Python/bytecodes.c

@@ -793,9 +793,12 @@ dummy_func(
             PyObject *temp = PyStackRef_AsPyObjectSteal(*target_local);
             PyObject *right_o = PyStackRef_AsPyObjectSteal(right);
             PyUnicode_Append(&temp, right_o);
-            *target_local = PyStackRef_FromPyObjectSteal(temp);
             Py_DECREF(right_o);
-            ERROR_IF(PyStackRef_IsNull(*target_local));
+            if (temp == NULL) {
+                *target_local = PyStackRef_NULL;
+                ERROR_IF(true);
+            }
+            *target_local = PyStackRef_FromPyObjectSteal(temp);
         #if TIER_ONE
             // The STORE_FAST is already done. This is done here in tier one,
             // and during trace projection in tier two: