fixed detection of updating table on which we select (BUG#6032)

mysql-test/r/view.result:
  Trys update table from which we select using views and subqueries
mysql-test/t/view.test:
  Trys update table from which we select using views and subqueries
sql/sql_acl.cc:
  fix of fix for bug BUG#5976
sql/sql_base.cc:
  protection against temporary tables which have not table->table->table_cache_key
  fixed unique check to skip the same table instences
sql/sql_delete.cc:
  removed next_independent to allow to check VIEW subqueries
sql/sql_insert.cc:
  removed next_independent to allow to check VIEW subqueries
sql/sql_parse.cc:
  removed next_independent to allow to check VIEW subqueries
sql/sql_update.cc:
  removed next_independent to allow to check VIEW subqueries
sql/sql_view.cc:
  removed next_independent to allow to check VIEW subqueries
  optimisation to mark as non-updatable views with subqueries by same table.
sql/table.h:
  removed next_independent to allow to check VIEW subqueries

mysql-test/r/view.result

@@ -1633,3 +1633,16 @@ use mysqltest;
 create view v1 as select * from t1;
 revoke all privileges on mysqltest.* from mysqltest_1@localhost;
 drop database mysqltest;
+create table t1 (s1 smallint);
+create view v1 as select * from t1 where 20 < (select (s1) from t1);
+insert into v1 values (30);
+ERROR HY000: The target table v1 of the INSERT is not updatable
+create view v2 as select * from t1;
+create view v3 as select * from t1 where 20 < (select (s1) from v2);
+insert into v3 values (30);
+ERROR HY000: The target table v3 of the INSERT is not updatable
+create view v4 as select * from v2 where 20 < (select (s1) from t1);
+insert into v4 values (30);
+ERROR HY000: You can't specify target table 'v4' for update in FROM clause
+drop view v4, v3, v2, v1;
+drop table t1;

mysql-test/t/view.test

@@ -1568,7 +1568,23 @@ connection user1;
 use mysqltest;
 create view v1 as select * from t1;
 
-
 connection root;
 revoke all privileges on mysqltest.* from mysqltest_1@localhost;
 drop database mysqltest;
+
+#
+# Trys update table from which we select using views and subqueries
+#
+create table t1 (s1 smallint);
+create view v1 as select * from t1 where 20 < (select (s1) from t1);
+-- error 1288
+insert into v1 values (30);
+create view v2 as select * from t1;
+create view v3 as select * from t1 where 20 < (select (s1) from v2);
+-- error 1288
+insert into v3 values (30);
+create view v4 as select * from v2 where 20 < (select (s1) from t1);
+-- error 1093
+insert into v4 values (30);
+drop view v4, v3, v2, v1;
+drop table t1;

sql/sql_acl.cc

@@ -3886,13 +3886,19 @@ int wild_case_compare(CHARSET_INFO *cs, const char *str,const char *wildstr)
 void fill_effective_table_privileges(THD *thd, GRANT_INFO *grant,
                                      const char *db, const char *table)
 {
+  /* --skip-grants */
+  if (!initialized)
+  {
+    grant->privilege= ~NO_ACCESS;             // everything is allowed
+    return;
+  }
+
   /* global privileges */
   grant->privilege= thd->master_access;
 
   /* db privileges */
   grant->privilege|= acl_get(thd->host, thd->ip, thd->priv_user, db, 0);
 
-  /* if privileges ignored (--skip-grant-tables) above is enough */
   if (!grant_option)
     return;
 

sql/sql_base.cc

@@ -593,7 +593,8 @@ TABLE_LIST *find_table_in_list(TABLE_LIST *table,
     {
       if ((!strcmp(table->db, db_name) &&
            !strcmp(table->real_name, table_name)) ||
-          (table->view &&
+          (table->view &&                      // it is VIEW and
+           table->table->table_cache_key &&    // it is not temporary table
            !strcmp(table->table->table_cache_key, db_name) &&
            !strcmp(table->table->table_name, table_name)))
         break;
@@ -618,6 +619,8 @@ TABLE_LIST *find_table_in_list(TABLE_LIST *table,
 
 TABLE_LIST* unique_table(TABLE_LIST *table, TABLE_LIST *table_list)
 {
+  DBUG_ENTER("unique_table");
+  DBUG_PRINT("enter", ("table alias: %s", table->alias));
   TABLE_LIST *res;
   const char *d_name= table->db, *t_name= table->real_name;
   char d_name_buff[MAX_ALIAS_NAME], t_name_buff[MAX_ALIAS_NAME];
@@ -644,13 +647,18 @@ TABLE_LIST* unique_table(TABLE_LIST *table, TABLE_LIST *table_list)
       return 0;
     }
   }
-  if ((res= find_table_in_global_list(table_list, d_name, t_name)) &&
-      res->table && res->table == table->table)
+
+  DBUG_PRINT("info", ("real table: %s.%s", d_name, t_name));
+  for(;;)
   {
-    // we found entry of this table try again.
-    return find_table_in_global_list(res->next_global, d_name, t_name);
+    if (!(res= find_table_in_global_list(table_list, d_name, t_name)) ||
+        !res->table || res->table != table->table)
+      break;
+    /* if we found entry of this table try again. */
+    table_list= res->next_global;
+    DBUG_PRINT("info", ("found same copy of table"));
   }
-  return res;
+  DBUG_RETURN(res);
 }
 
 

sql/sql_delete.cc

@@ -293,7 +293,7 @@ int mysql_prepare_delete(THD *thd, TABLE_LIST *table_list, Item **conds)
     my_error(ER_NON_UPDATABLE_TABLE, MYF(0), table_list->alias, "DELETE");
     DBUG_RETURN(-1);
   }
-  if (unique_table(table_list, table_list->next_independent()))
+  if (unique_table(table_list, table_list->next_global))
   {
     my_error(ER_UPDATE_TABLE_USED, MYF(0), table_list->real_name);
     DBUG_RETURN(-1);

sql/sql_insert.cc

@@ -641,7 +641,7 @@ int mysql_prepare_insert(THD *thd, TABLE_LIST *table_list, TABLE *table,
         setup_fields(thd, 0, table_list, update_values, 0, 0, 0))))
     DBUG_RETURN(-1);
 
-  if (unique_table(table_list, table_list->next_independent()))
+  if (unique_table(table_list, table_list->next_global))
   {
     my_error(ER_UPDATE_TABLE_USED, MYF(0), table_list->real_name);
     DBUG_RETURN(-1);

sql/sql_parse.cc

@@ -2810,7 +2810,7 @@ unsent_create_error:
         Is table which we are changing used somewhere in other parts of
         query
       */
-      if (unique_table(first_table, all_tables->next_independent()))
+      if (unique_table(first_table, all_tables->next_global))
       {
         /* Using same table for INSERT and SELECT */
         select_lex->options |= OPTION_BUFFER_RESULT;

sql/sql_update.cc

@@ -529,7 +529,7 @@ int mysql_prepare_update(THD *thd, TABLE_LIST *table_list,
     DBUG_RETURN(-1);
 
   /* Check that we are not using table that we are updating in a sub select */
-  if (unique_table(table_list, table_list->next_independent()))
+  if (unique_table(table_list, table_list->next_global))
   {
     my_error(ER_UPDATE_TABLE_USED, MYF(0), table_list->real_name);
     DBUG_RETURN(-1);

sql/sql_view.cc

@@ -382,6 +382,7 @@ static LEX_STRING view_file_type[]= {{(char*)"VIEW", 4}};
 static int mysql_register_view(THD *thd, TABLE_LIST *view,
 			       enum_view_create_mode mode)
 {
+  LEX *lex= thd->lex;
   char buff[4096];
   String str(buff,(uint32) sizeof(buff), system_charset_info);
   char md5[33];
@@ -395,7 +396,7 @@ static int mysql_register_view(THD *thd, TABLE_LIST *view,
   {
     ulong sql_mode= thd->variables.sql_mode & MODE_ANSI_QUOTES;
     thd->variables.sql_mode&= ~MODE_ANSI_QUOTES;
-    thd->lex->unit.print(&str);
+    lex->unit.print(&str);
     thd->variables.sql_mode|= sql_mode;
   }
   str.append('\0');
@@ -474,21 +475,21 @@ static int mysql_register_view(THD *thd, TABLE_LIST *view,
   view->calc_md5(md5);
   view->md5.str= md5;
   view->md5.length= 32;
-  can_be_merged= thd->lex->can_be_merged();
-  if (thd->lex->create_view_algorithm == VIEW_ALGORITHM_MERGE &&
-      !thd->lex->can_be_merged())
+  can_be_merged= lex->can_be_merged();
+  if (lex->create_view_algorithm == VIEW_ALGORITHM_MERGE &&
+      !lex->can_be_merged())
   {
     push_warning(thd, MYSQL_ERROR::WARN_LEVEL_WARN, ER_WARN_VIEW_MERGE,
                  ER(ER_WARN_VIEW_MERGE));
-    thd->lex->create_view_algorithm= VIEW_ALGORITHM_UNDEFINED;
+    lex->create_view_algorithm= VIEW_ALGORITHM_UNDEFINED;
   }
-  view->algorithm= thd->lex->create_view_algorithm;
-  view->with_check= thd->lex->create_view_check;
+  view->algorithm= lex->create_view_algorithm;
+  view->with_check= lex->create_view_check;
   if ((view->updatable_view= (can_be_merged &&
                               view->algorithm != VIEW_ALGORITHM_TMPTABLE)))
   {
     /* TODO: change here when we will support UNIONs */
-    for (TABLE_LIST *tbl= (TABLE_LIST *)thd->lex->select_lex.table_list.first;
+    for (TABLE_LIST *tbl= (TABLE_LIST *)lex->select_lex.table_list.first;
          tbl;
          tbl= tbl->next_local)
     {
@@ -500,6 +501,26 @@ static int mysql_register_view(THD *thd, TABLE_LIST *view,
     }
   }
 
+  /*
+    Check that table of main select do not used in subqueries.
+
+    This test can catch only very simple cases of such non-updateable views,
+    all other will be detected before updating commands execution.
+    (it is more optimisation then real check)
+
+    NOTE: this skip cases of using table via VIEWs, joined VIEWs, VIEWs with
+    UNION
+  */
+  if (view->updatable_view &&
+      !lex->select_lex.next_select() &&
+      !((TABLE_LIST*)lex->select_lex.table_list.first)->next_local &&
+      find_table_in_global_list(lex->query_tables->next_global,
+				lex->query_tables->db,
+				lex->query_tables->real_name))
+  {
+    view->updatable_view= 0;
+  }
+
   if (view->with_check != VIEW_CHECK_NONE &&
       !view->updatable_view)
   {
@@ -698,13 +719,12 @@ mysql_make_view(File_parser *parser, TABLE_LIST *table)
       tables just after VIEW instead of tail of list, to be able check that
       table is unique. Also we store old next table for the same purpose.
     */
-    table->old_next= table->next_global;
     if (view_tables)
     {
       if (table->next_global)
       {
+        view_tables_tail->next_global= table->next_global;
         table->next_global->prev_global= &view_tables_tail->next_global;
-        view_tables_tail->next_global= table->old_next;
       }
       else
       {

sql/table.h

@@ -232,8 +232,6 @@ typedef struct st_table_list
   st_table_list	*ancestor;
   /* most upper view this table belongs to */
   st_table_list	*belong_to_view;
-  /* next_global before adding VIEW tables */
-  st_table_list	*old_next;
   Item          *where;                 /* VIEW WHERE clause condition */
   Item          *check_option;          /* WITH CHECK OPTION condition */
   LEX_STRING	query;			/* text of (CRETE/SELECT) statement */
@@ -286,12 +284,6 @@ typedef struct st_table_list
   bool setup_ancestor(THD *thd, Item **conds, uint8 check_option);
   bool placeholder() {return derived || view; }
   void print(THD *thd, String *str);
-  inline st_table_list *next_independent()
-  {
-    if (view)
-      return old_next;
-    return next_global;
-  }
 } TABLE_LIST;
 
 class Item;