BUG#26881798: SERVER EXITS WHEN PRIMARY KEY IN MYSQL.PROC

              IS DROPPED

ANALYSIS:
=========
It is advised not to tamper with the system tables.
When primary key is dropped from a system table, certain
operations on the table which tries to access the table key
information may lead to server exit.

FIX:
====
An appropriate error is now reported in such a case.

1 files changed, 14 insertions, 2 deletions

diff --git a/sql/table.cc b/sql/table.cc
index 5bc3ccdbf39..46397b794ee 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -1,5 +1,5 @@
 /*
-   Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -3013,7 +3013,7 @@ Table_check_intact::check(TABLE *table, const TABLE_FIELD_DEF *table_def)
 
   /* Whether the table definition has already been validated. */
   if (table->s->table_field_def_cache == table_def)
-    DBUG_RETURN(FALSE);
+    goto end;
 
   if (table->s->fields != table_def->count)
   {
@@ -3129,6 +3129,18 @@ Table_check_intact::check(TABLE *table, const TABLE_FIELD_DEF *table_def)
   if (! error)
     table->s->table_field_def_cache= table_def;
 
+end:
+
+  if (has_keys && !error && !table->key_info)
+  {
+    my_printf_error(ER_UNKNOWN_ERROR,
+                    "The table '%s.%s' does not have the necessary key(s) "
+                    "defined on it. Please check the table definition and "
+                    "create index(s) accordingly.", MYF(0),
+                    table->s->db.str, table->s->table_name.str);
+    error= TRUE;
+  }
+
   DBUG_RETURN(error);
 }