Add _PyBytes_CheckOverflow() to share code

Author: vstinner

Include/internal/pycore_bytesobject.h

@@ -81,6 +81,13 @@ extern int _PyBytes_ResizeKeepOnError(PyObject **pv, Py_ssize_t newsize);
 extern int _PyBytes_IsMutable(PyObject *obj);
 #endif
 
+#ifdef Py_DEBUG
+extern void _PyBytes_CheckOverflow(
+    PyObject *op,
+    void *addr,
+    const char *type_name);
+#endif
+
 /* --- PyBytesWriter ------------------------------------------------------ */
 
 struct PyBytesWriter {

Objects/bytearrayobject.c

@@ -1272,18 +1272,9 @@ static void
 bytearray_dealloc(PyObject *op)
 {
     PyByteArrayObject *self = _PyByteArray_CAST(op);
-
 #ifdef Py_DEBUG
-    // Make sure that the trailing null byte was not modified
     if (self->ob_bytes_object != NULL) {
-        char *data = PyByteArray_AS_STRING(self);
-        Py_ssize_t size = PyByteArray_GET_SIZE(self);
-        if (data[size] != '\0') {
-            _Py_FatalErrorFormat(__func__,
-                                 "Buffer overflow detected in bytearray "
-                                 "object %p at position %zd",
-                                 self, size);
-        }
+        _PyBytes_CheckOverflow(self->ob_bytes_object, op, "bytearray");
     }
 #endif
 

Objects/bytesobject.c

@@ -3192,20 +3192,26 @@ bytes_iteritem(PyObject *obj, Py_ssize_t index)
 }
 
 #ifdef Py_DEBUG
-static void
-bytes_dealloc(PyObject *op)
+void
+_PyBytes_CheckOverflow(PyObject *self, void *addr, const char *type_name)
 {
     // Make sure that the trailing null byte was not modified
-    PyBytesObject *self = _PyBytes_CAST(op);
     char *data = PyBytes_AS_STRING(self);
     Py_ssize_t size = PyBytes_GET_SIZE(self);
     if (data[size] != '\0') {
         _Py_FatalErrorFormat(__func__,
-                             "Buffer overflow detected in bytes object %p "
+                             "Buffer overflow detected in %s object %p "
                              "at position %zd",
-                             self, size);
+                             type_name, addr, size);
     }
+}
 
+
+static void
+bytes_dealloc(PyObject *op)
+{
+    PyBytesObject *self = _PyBytes_CAST(op);
+    _PyBytes_CheckOverflow(op, op, "bytes");
     Py_TYPE(self)->tp_free((PyObject *)self);
 }
 #endif