Bug#27430 "Crash in subquery code when in PS and table DDL changed after

 PREPARE", review fixes:
- make the patch follow the specification of WL#4166 and remove  
the new error that was originally introduced.
Now the client never gets an error from reprepare, unless it failed.
I.e. even if the statement at hand returns a completely different
result set, this is not considered a server error.
The C API library, that can not handle this situation, was modified to
return a client error.
Added additional test coverage.

1 files changed, 3 insertions, 4 deletions

diff --git a/sql/sql_prepare.cc b/sql/sql_prepare.cc
index 3036b36f8fa..ca72d1c1613 100644
--- a/sql/sql_prepare.cc
+++ b/sql/sql_prepare.cc
@@ -3315,7 +3315,7 @@ Prepared_statement::reprepare()
   @param[in]  copy  the re-prepared prepared statement to verify
                     the metadata of
 
-  @retval TRUE  error, ER_PS_NEED_REBIND is reported
+  @retval TRUE  error, ER_PS_REBIND is reported
   @retval FALSE statement return no or compatible metadata
 */
 
@@ -3333,9 +3333,8 @@ bool Prepared_statement::validate_metadata(Prepared_statement *copy)
   if (lex->select_lex.item_list.elements !=
       copy->lex->select_lex.item_list.elements)
   {
-    /** Column counts mismatch. */
-    my_error(ER_PS_REBIND, MYF(0));
-    return TRUE;
+    /** Column counts mismatch, update the client */
+    thd->server_status|= SERVER_STATUS_METADATA_CHANGED;
   }
 
   return FALSE;