Revert offending part of MDEV-9519: Data corruption will happen on th…

…e Galera cluster size change

This will allow test binlog.binlog_stm_binlog to pass more often.
Note that this is not a real fix to that test failure.

sql/handler.cc

@@ -3016,7 +3016,7 @@ int handler::update_auto_increment()
   bool append= FALSE;
   THD *thd= table->in_use;
   struct system_variables *variables= &thd->variables;
-  int tmp;
+  int result=0, tmp;
   enum enum_check_fields save_count_cuted_fields;
   DBUG_ENTER("handler::update_auto_increment");
 
@@ -3152,18 +3152,27 @@ int handler::update_auto_increment()
     */
     if (thd->killed == KILL_BAD_DATA ||
         nr > table->next_number_field->get_max_int_value())
-      DBUG_RETURN(HA_ERR_AUTOINC_ERANGE);
-    /*
-      Field refused this value (overflow) and truncated it, use the result
-      of the truncation (which is going to be inserted); however we try to
-      decrease it to honour auto_increment_* variables.
-      That will shift the left bound of the reserved interval, we don't
-      bother shifting the right bound (anyway any other value from this
-      interval will cause a duplicate key).
-    */
-    nr= prev_insert_id(table->next_number_field->val_int(), variables);
-    if (unlikely(table->next_number_field->store((longlong)nr, TRUE)))
-      nr= table->next_number_field->val_int();
+    {
+      /*
+        It's better to return an error here than getting a confusing
+        'duplicate key error' later.
+      */
+      result= HA_ERR_AUTOINC_ERANGE;
+    }
+    else
+    {
+      /*
+        Field refused this value (overflow) and truncated it, use the result
+        of the truncation (which is going to be inserted); however we try to
+        decrease it to honour auto_increment_* variables.
+        That will shift the left bound of the reserved interval, we don't
+        bother shifting the right bound (anyway any other value from this
+        interval will cause a duplicate key).
+      */
+      nr= prev_insert_id(table->next_number_field->val_int(), variables);
+      if (unlikely(table->next_number_field->store((longlong)nr, TRUE)))
+        nr= table->next_number_field->val_int();
+    }
   }
   if (append)
   {
@@ -3188,6 +3197,9 @@ int handler::update_auto_increment()
   */
   insert_id_for_cur_row= nr;
 
+  if (result)                                   // overflow
+    DBUG_RETURN(result);
+
   /*
     Set next insert id to point to next auto-increment value to be able to
     handle multi-row statements.