Fix for a bug #6996

.bzrignore

@@ -943,3 +943,5 @@ ac_available_languages_fragment
 libmysqld/ha_archive.cc
 libmysqld/ha_example.cc
 libmysqld/ha_tina.cc
+analyse.test
+client/mysqladmin.c

libmysql/libmysql.c

@@ -4413,6 +4413,12 @@ mysql_stmt_data_seek(MYSQL_STMT *stmt, my_ulonglong row)
   for (; tmp && row; --row, tmp= tmp->next)
     ;
   stmt->data_cursor= tmp;
+  if (!row && tmp)
+  {
+       /*  Rewind the counter */
+    stmt->read_row_func= stmt_read_row_buffered;
+    stmt->state= MYSQL_STMT_EXECUTE_DONE;
+  }
   DBUG_VOID_RETURN;
 }
 

tests/client_test.c

@@ -11389,6 +11389,67 @@ static void test_conversion()
   myquery(rc);
 }
 
+static void test_rewind(void)
+{
+  MYSQL_STMT *stmt;
+  MYSQL_BIND bind;
+  int rc = 0;
+  const char *stmt_text;
+  long unsigned int length=4, Data=0;
+  my_bool isnull=0;
+
+  myheader("test_rewind");
+
+  stmt_text= "CREATE TABLE t1 (a int)";
+  rc= mysql_real_query(mysql, stmt_text, strlen(stmt_text));
+  myquery(rc);
+  stmt_text= "INSERT INTO t1 VALUES(2),(3),(4)";
+  rc= mysql_real_query(mysql, stmt_text, strlen(stmt_text));
+  myquery(rc);
+
+  stmt= mysql_stmt_init(mysql);
+
+  stmt_text= "SELECT * FROM t1";
+  rc= mysql_stmt_prepare(stmt, stmt_text, strlen(stmt_text));
+  check_execute(stmt, rc);
+
+  bzero(&bind,sizeof(MYSQL_BIND));
+  bind.buffer_type= MYSQL_TYPE_LONG;
+  bind.buffer= (void *)&Data; /* this buffer won't be altered */
+  bind.length= &length;
+  bind.is_null= &isnull;
+
+  rc= mysql_stmt_execute(stmt);
+  check_execute(stmt, rc);
+
+  rc= mysql_stmt_store_result(stmt);
+  DIE_UNLESS(rc == 0);
+
+  rc= mysql_stmt_bind_result(stmt, &bind);
+  DIE_UNLESS(rc == 0);
+
+  /* retreive all result sets till we are at the end */
+  while(!mysql_stmt_fetch(stmt))
+      printf("fetched result:%ld\n", Data);
+
+  DIE_UNLESS(rc != MYSQL_NO_DATA);
+
+  /* seek to the first row */
+  mysql_stmt_data_seek(stmt, 0);
+
+  /* now we should be able to fetch the results again */
+  /* but mysql_stmt_fetch returns MYSQL_NO_DATA */
+  while(!(rc= mysql_stmt_fetch(stmt)))
+      printf("fetched result after seek:%ld\n", Data);
+  
+  DIE_UNLESS(rc == MYSQL_NO_DATA);
+
+  stmt_text= "DROP TABLE t1";
+  rc= mysql_real_query(mysql, stmt_text, strlen(stmt_text));
+  myquery(rc);
+  rc= mysql_stmt_free_result(stmt);
+  rc= mysql_stmt_close(stmt);
+}
 
 /*
   Read and parse arguments and MySQL options from my.cnf
@@ -11594,6 +11655,7 @@ static struct my_tests_st my_tests[]= {
   { "test_datetime_ranges", test_datetime_ranges },
   { "test_bug4172", test_bug4172 },
   { "test_conversion", test_conversion },
+  { "test_rewind", test_rewind },
   { 0, 0 }
 };