MDEV-20517 Assertion `!is_expensive()' failed in Item::value_depends_on_sql_mode_const_item

1 files changed, 12 insertions, 7 deletions

diff --git a/sql/item_func.cc b/sql/item_func.cc
index d11b56f2aad..5deeccc9265 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -1423,17 +1423,22 @@ bool Item_func_minus::fix_length_and_dec()
 {
   if (Item_num_op::fix_length_and_dec())
     return TRUE;
-  m_sql_mode_dependency= Item_func::value_depends_on_sql_mode();
-  if (unsigned_flag)
-  {
-    m_sql_mode_dependency|= Sql_mode_dependency(0,MODE_NO_UNSIGNED_SUBTRACTION);
-    if (current_thd->variables.sql_mode & MODE_NO_UNSIGNED_SUBTRACTION)
-      unsigned_flag= false;
-  }
+  if ((m_depends_on_sql_mode_no_unsigned_subtraction= unsigned_flag) &&
+      (current_thd->variables.sql_mode & MODE_NO_UNSIGNED_SUBTRACTION))
+    unsigned_flag= false;
   return FALSE;
 }
 
 
+Sql_mode_dependency Item_func_minus::value_depends_on_sql_mode() const
+{
+  Sql_mode_dependency dep= Item_func_additive_op::value_depends_on_sql_mode();
+  if (m_depends_on_sql_mode_no_unsigned_subtraction)
+    dep|= Sql_mode_dependency(0, MODE_NO_UNSIGNED_SUBTRACTION);
+  return dep;
+}
+
+
 double Item_func_minus::real_op()
 {
   double value= args[0]->val_real() - args[1]->val_real();