MDEV-5273 Prepared statement doesn't return metadata after prepare.

        SHOW SLAVE STATUS fixed.

sql/slave.h

@@ -207,6 +207,8 @@ int mysql_table_dump(THD* thd, const char* db,
 int fetch_master_table(THD* thd, const char* db_name, const char* table_name,
 		       Master_info* mi, MYSQL* mysql, bool overwrite);
 
+void show_master_info_get_fields(THD *thd, List<Item> *field_list,
+                                     bool full, size_t gtid_pos_length);
 bool show_master_info(THD* thd, Master_info* mi, bool full);
 bool show_all_master_info(THD* thd);
 bool show_binlog_info(THD* thd);

sql/sql_prepare.cc

@@ -104,6 +104,7 @@ When one supplies long data for a placeholder:
                          // mysql_handle_derived
 #include "sql_cursor.h"
 #include "sql_show.h"
+#include "slave.h"
 #include "sp_head.h"
 #include "sp.h"
 #include "sp_cache.h"
@@ -1892,6 +1893,29 @@ static bool mysql_test_show_grants(Prepared_statement *stmt)
 }
 
 
+/**
+  Validate and prepare for execution SHOW SLAVE STATUS statement.
+
+  @param stmt               prepared statement
+
+  @retval
+    FALSE             success
+  @retval
+    TRUE              error, error message is set in THD
+*/
+
+static bool mysql_test_show_slave_status(Prepared_statement *stmt)
+{
+  DBUG_ENTER("mysql_test_show_slave_status");
+  THD *thd= stmt->thd;
+  List<Item> fields;
+
+  show_master_info_get_fields(thd, &fields, 0, 0);
+    
+  DBUG_RETURN(send_stmt_metadata(thd, stmt, &fields));
+}
+
+
 /**
   @brief Validate and prepare for execution CREATE VIEW statement
 
@@ -2246,6 +2270,13 @@ static bool check_prepared_statement(Prepared_statement *stmt)
       DBUG_RETURN(FALSE);
     }
     break;
+  case SQLCOM_SHOW_SLAVE_STAT:
+    if (!(res= mysql_test_show_slave_status(stmt)))
+    {
+      /* Statement and field info has already been sent */
+      DBUG_RETURN(FALSE);
+    }
+    break;
   case SQLCOM_CREATE_VIEW:
     if (lex->create_view_mode == VIEW_ALTER)
     {

tests/mysql_client_test.c

@@ -443,6 +443,13 @@ static void test_prepare_simple()
   DIE_UNLESS(mysql_stmt_field_count(stmt) == 1);
   mysql_stmt_close(stmt);
 
+  /* show slave status */
+  strmov(query, "SHOW SLAVE STATUS");
+  stmt= mysql_simple_prepare(mysql, query);
+  check_stmt(stmt);
+  DIE_UNLESS(mysql_stmt_field_count(stmt) == 47);
+  mysql_stmt_close(stmt);
+
   /* now fetch the results ..*/
   rc= mysql_commit(mysql);
   myquery(rc);