Fixed bug#21098119: GCOL WITH MATCH/AGAINST --> ASSERTION FAILED:

TR && TR->TABLE->FILE

Function allows_search_on_non_indexed_columns checks whether the storage engines
support non-index columns to do fulltext search, which requires a Not-Null
TABLE_LIST pointer as its argument.

During alter...table, a temporary table is created to help to support inplace
operation and Item_field->table_ref is NULL for tempoaray table. If old
table has generated columns which include match()...against expression,
allows_search_on_non_index_columns will be called during open the temporary table.
Therefore, the Item_field->table_ref is NULL at this moment, which triggers the
assertion.

The solution to fix this bug is to replace the TABLE_LIST pointer arugument into
TABLE pointer.

Author: Benny Wang

mysql-test/suite/gcol/inc/gcol_blocked_sql_funcs_main.inc

@@ -320,3 +320,13 @@ drop table t1;
 --echo #
 --echo # Constant expression
 create table t1 (a int generated always as (PI()) virtual);
+drop table t1;
+
+--echo # bug#21098119: GCOL WITH MATCH/AGAINST -->
+--echo # ASSERTION FAILED: TR && TR->TABLE->FILE
+--echo #
+create table t1 (a int);
+--error ER_GENERATED_COLUMN_FUNCTION_IS_NOT_ALLOWED
+alter table t1 add column r blob generated always
+as (match(a) against ('' in boolean mode)) virtual;
+drop table t1;

mysql-test/suite/gcol/r/gcol_blocked_sql_funcs_innodb.result

@@ -221,6 +221,15 @@ drop table t1;
 #
 # Constant expression
 create table t1 (a int generated always as (PI()) virtual);
+drop table t1;
+# bug#21098119: GCOL WITH MATCH/AGAINST -->
+# ASSERTION FAILED: TR && TR->TABLE->FILE
+#
+create table t1 (a int);
+alter table t1 add column r blob generated always
+as (match(a) against ('' in boolean mode)) virtual;
+ERROR HY000: Expression of generated column 'r' contains a disallowed function.
+drop table t1;
 DROP VIEW  IF EXISTS v1,v2;
 DROP TABLE IF EXISTS t1,t2,t3;
 DROP PROCEDURE IF EXISTS p1;

mysql-test/suite/gcol/r/gcol_blocked_sql_funcs_myisam.result

@@ -223,6 +223,15 @@ drop table t1;
 #
 # Constant expression
 create table t1 (a int generated always as (PI()) virtual);
+drop table t1;
+# bug#21098119: GCOL WITH MATCH/AGAINST -->
+# ASSERTION FAILED: TR && TR->TABLE->FILE
+#
+create table t1 (a int);
+alter table t1 add column r blob generated always
+as (match(a) against ('' in boolean mode)) virtual;
+ERROR HY000: Expression of generated column 'r' contains a disallowed function.
+drop table t1;
 DROP VIEW  IF EXISTS v1,v2;
 DROP TABLE IF EXISTS t1,t2,t3;
 DROP PROCEDURE IF EXISTS p1;

sql/item_func.cc

@@ -7461,7 +7461,7 @@ bool Item_func_match::fix_fields(THD *thd, Item **ref)
       return TRUE;
     }
     allows_multi_table_search &= 
-      allows_search_on_non_indexed_columns(((Item_field *)item)->table_ref);
+      allows_search_on_non_indexed_columns(((Item_field *)item)->field->table);
   }
 
   /*
@@ -7557,7 +7557,7 @@ bool Item_func_match::fix_index()
   */
   if (!fixed)
   {
-    if (allows_search_on_non_indexed_columns(table_ref))
+    if (allows_search_on_non_indexed_columns(table_ref->table))
       key= NO_SUCH_KEY;
 
     return false;
@@ -7629,7 +7629,7 @@ bool Item_func_match::fix_index()
   }
 
 err:
-  if (table_ref != 0 && allows_search_on_non_indexed_columns(table_ref))
+  if (table_ref != 0 && allows_search_on_non_indexed_columns(table_ref->table))
   {
     key=NO_SUCH_KEY;
     return 0;

sql/item_func.h

@@ -2569,17 +2569,17 @@ class Item_func_match :public Item_real_func
      @retval true if BOOLEAN search on non-indexed columns is supported
      @retval false otherwise
    */
-  bool allows_search_on_non_indexed_columns(const TABLE_LIST *tr)
+  bool allows_search_on_non_indexed_columns(const TABLE *tr)
   {
     // Only Boolean search may support non_indexed columns
     if (!(flags & FT_BOOL))
       return false;
 
-    DBUG_ASSERT(tr && tr->table->file);
+    DBUG_ASSERT(tr && tr->file);
 
     // Assume that if extended fulltext API is not supported,
     // non-indexed columns are allowed.  This will be true for MyISAM.
-    if ((tr->table->file->ha_table_flags() & HA_CAN_FULLTEXT_EXT) == 0)
+    if ((tr->file->ha_table_flags() & HA_CAN_FULLTEXT_EXT) == 0)
       return true;
 
     return false;