Fixed bug #36055: mysql_upgrade doesn't really 'upgrade' tables

The REPAIR TABLE ... USE_FRM query silently corrupts data of tables
with old .FRM file version.
The mysql_upgrade client program or the REPAIR TABLE query (without
the USE_FRM clause) can't prevent this trouble, because in the
common case they don't upgrade .FRM file to compatible structure.

1. Evaluation of the REPAIR TABLE ... USE_FRM query has been
   modified to reject such tables with the message:
   "Failed repairing incompatible .FRM file".

2. REPAIR TABLE query (without USE_FRM clause) evaluation has been
   modified to upgrade .FRM files to current version.

3. CHECK TABLE ... FOR UPGRADE query evaluation has been modified
   to return error status when .FRM file has incompatible version.

4. mysql_upgrade and mysqlcheck client programs call CHECK TABLE
   FOR UPGRADE and REPAIR TABLE queries, so their behaviors have
   been changed too to upgrade .FRM files with incompatible
   version numbers.

1 files changed, 7 insertions, 0 deletions

diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 9e1a8151e3a..f1de63892d5 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -2118,6 +2118,13 @@ static int prepare_for_repair(THD* thd, TABLE_LIST *table_list,
   const char **ext= table->file->bas_ext();
   MY_STAT stat_info;
 
+  if (table->s->frm_version != FRM_VER_TRUE_VARCHAR)
+  {
+    error= send_check_errmsg(thd, table_list, "repair",
+                             "Failed reparing incompatible .FRM file");
+    goto end;
+  }
+
   /*
     Check if this is a table type that stores index and data separately,
     like ISAM or MyISAM. We assume fixed order of engine file name