c

1 files changed, 13 insertions, 1 deletions

diff --git a/sql/field.cc b/sql/field.cc
index d913e395b1a..6e1851d89d1 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -7860,7 +7860,19 @@ String *Field_set::val_str(String *val_buffer,
   ulonglong tmp=(ulonglong) Field_enum::val_int();
   uint bitnr=0;
 
-  val_buffer->set("", 0, field_charset);
+  if (tmp == 0)
+  {
+    /*
+      Some callers expect *val_buffer to contain the result,
+      so we assign to it, rather than doing 'return &empty_set_string.
+     */
+    *val_buffer= empty_set_string;
+    return val_buffer;
+  }
+
+  val_buffer->set_charset(field_charset);
+  val_buffer->length(0);
+
   while (tmp && bitnr < (uint) typelib->count)
   {
     if (tmp & 1)