Fixed mdev-15119 CTE, referencing another CTE, that is declared after,

                 does not return error

Corrected the code of st_select_lex::find_table_def_in_with_clauses() for
a proper identification of CTE references used in embedded CTEs.

mysql-test/r/cte_nonrecursive.result

@@ -1379,3 +1379,22 @@ USE db1;
 WITH cte AS (SELECT 1 AS a) SELECT db1.cte.a FROM db1.cte;
 ERROR 42S02: Table 'db1.cte' doesn't exist
 DROP DATABASE db1;
+USE test;
+#
+# MDEV-15119: CTE c2 specified after CTE c1 and is used in
+#             CTE c3 that is embedded into the spec of c1
+#
+CREATE TABLE t1 (i int);
+INSERT INTO t1 VALUES (1),(2),(3);
+WITH c1 AS (WITH c3 AS (SELECT * FROM c2) SELECT * FROM c3),
+c2 AS (SELECT * FROM t1)
+SELECT * FROM c1;
+ERROR 42S02: Table 'test.c2' doesn't exist
+WITH RECURSIVE c1 AS (WITH c3 AS (SELECT * FROM c2) SELECT * FROM c3),
+c2 AS (SELECT * FROM t1)
+SELECT * FROM c1;
+i
+1
+2
+3
+DROP TABLE t1;

mysql-test/t/cte_nonrecursive.test

@@ -944,3 +944,23 @@ USE db1;
 WITH cte AS (SELECT 1 AS a) SELECT db1.cte.a FROM db1.cte;
 
 DROP DATABASE db1;
+USE test;
+
+--echo #
+--echo # MDEV-15119: CTE c2 specified after CTE c1 and is used in
+--echo #             CTE c3 that is embedded into the spec of c1
+--echo #
+
+CREATE TABLE t1 (i int);
+INSERT INTO t1 VALUES (1),(2),(3);
+
+--error ER_NO_SUCH_TABLE
+WITH c1 AS (WITH c3 AS (SELECT * FROM c2) SELECT * FROM c3),
+     c2 AS (SELECT * FROM t1)
+SELECT * FROM c1;
+
+WITH RECURSIVE c1 AS (WITH c3 AS (SELECT * FROM c2) SELECT * FROM c3),
+     c2 AS (SELECT * FROM t1)
+SELECT * FROM c1;
+
+DROP TABLE t1;

sql/sql_cte.cc

@@ -1006,23 +1006,20 @@ bool With_element::is_anchor(st_select_lex *sel)
 
 With_element *st_select_lex::find_table_def_in_with_clauses(TABLE_LIST *table)
 {
-  st_select_lex_unit *master_unit= NULL;
   With_element *found= NULL;
-  for (st_select_lex *sl= this;
-       sl;
-       sl= master_unit->outer_select())
+  st_select_lex_unit *master_unit;
+  st_select_lex *outer_sl;
+  for (st_select_lex *sl= this; sl; sl= outer_sl)
   {
-    With_element *with_elem= sl->get_with_element();
     /* 
       If sl->master_unit() is the spec of a with element then the search for 
       a definition was already done by With_element::check_dependencies_in_spec
       and it was unsuccesful. Yet for units cloned from the spec it has not 
       been done yet.
     */
-    With_clause *attached_with_clause=sl->get_with_clause();
-    if (attached_with_clause &&
-        (found= attached_with_clause->find_table_def(table, NULL)))
-      break;
+    master_unit= sl->master_unit();
+    outer_sl= master_unit->outer_select();
+    With_element *with_elem= sl->get_with_element();
     if (with_elem)
     {
       With_clause *containing_with_clause= with_elem->get_owner();
@@ -1030,9 +1027,16 @@ With_element *st_select_lex::find_table_def_in_with_clauses(TABLE_LIST *table)
                                NULL : with_elem;
       if ((found= containing_with_clause->find_table_def(table, barrier)))
         break;
-      sl= sl->master_unit()->outer_select(); 
+      if (outer_sl && !outer_sl->get_with_element())
+        break;
+    }
+    else
+    {
+      With_clause *attached_with_clause= sl->get_with_clause();
+      if (attached_with_clause &&
+          (found= attached_with_clause->find_table_def(table, NULL)))
+        break;
     }
-    master_unit= sl->master_unit();
     /* Do not look for the table's definition beyond the scope of the view */
     if (master_unit->is_view)
       break;