Fixed a crash in a EXIT/CONTINUE with an unknown identifier in the WHEN clause

The crash happened because of a wrong reset_lex() .. restore_lex() sequence.
The Item in WHERE clause and the corresponding sp_instr_jump_if_not() were
erroneously created using different LEX.

mysql-test/suite/compat/oracle/r/sp.result

@@ -1021,3 +1021,48 @@ SELECT f1(3), f1(4), f1(5), f1(6) FROM DUAL;
 f1(3)	f1(4)	f1(5)	f1(6)
 3	4	4	5
 DROP FUNCTION f1;
+#
+# Testing behaviour of unknown identifiers in EXIT and CONTINUE statements
+#
+CREATE PROCEDURE p1
+AS
+BEGIN
+LOOP
+EXIT WHEN unknown_ident IS NULL;
+END LOOP;
+END$$
+CALL p1;
+ERROR 42S22: Unknown column 'unknown_ident' in 'field list'
+DROP PROCEDURE p1;
+CREATE PROCEDURE p1
+AS
+BEGIN
+<<label>>
+LOOP
+EXIT label WHEN unknown_ident IS NULL;
+END LOOP;
+END$$
+CALL p1;
+ERROR 42S22: Unknown column 'unknown_ident' in 'field list'
+DROP PROCEDURE p1;
+CREATE PROCEDURE p1
+AS
+BEGIN
+LOOP
+CONTINUE WHEN unknown_ident IS NULL;
+END LOOP;
+END$$
+CALL p1;
+ERROR 42S22: Unknown column 'unknown_ident' in 'field list'
+DROP PROCEDURE p1;
+CREATE PROCEDURE p1
+AS
+BEGIN
+<<label>>
+LOOP
+CONTINUE label WHEN unknown_ident IS NULL;
+END LOOP;
+END$$
+CALL p1;
+ERROR 42S22: Unknown column 'unknown_ident' in 'field list'
+DROP PROCEDURE p1;

mysql-test/suite/compat/oracle/t/sp.test

@@ -1097,3 +1097,64 @@ END;
 DELIMITER ;/
 SELECT f1(3), f1(4), f1(5), f1(6) FROM DUAL;
 DROP FUNCTION f1;
+
+--echo #
+--echo # Testing behaviour of unknown identifiers in EXIT and CONTINUE statements
+--echo #
+
+DELIMITER $$;
+CREATE PROCEDURE p1
+AS
+BEGIN
+  LOOP
+    EXIT WHEN unknown_ident IS NULL;
+  END LOOP;
+END$$
+DELIMITER ;$$
+--error ER_BAD_FIELD_ERROR
+CALL p1;
+DROP PROCEDURE p1;
+
+
+DELIMITER $$;
+CREATE PROCEDURE p1
+AS
+BEGIN
+  <<label>>
+  LOOP
+    EXIT label WHEN unknown_ident IS NULL;
+  END LOOP;
+END$$
+DELIMITER ;$$
+--error ER_BAD_FIELD_ERROR
+CALL p1;
+DROP PROCEDURE p1;
+
+
+DELIMITER $$;
+CREATE PROCEDURE p1
+AS
+BEGIN
+  LOOP
+    CONTINUE WHEN unknown_ident IS NULL;
+  END LOOP;
+END$$
+DELIMITER ;$$
+--error ER_BAD_FIELD_ERROR
+CALL p1;
+DROP PROCEDURE p1;
+
+
+DELIMITER $$;
+CREATE PROCEDURE p1
+AS
+BEGIN
+  <<label>>
+  LOOP
+    CONTINUE label WHEN unknown_ident IS NULL;
+  END LOOP;
+END$$
+DELIMITER ;$$
+--error ER_BAD_FIELD_ERROR
+CALL p1;
+DROP PROCEDURE p1;

sql/sql_lex.cc

@@ -5637,7 +5637,6 @@ bool LEX::sp_exit_block(THD *thd, sp_label *lab, Item *when)
   if (!when)
     return sp_exit_block(thd, lab);
 
-  sphead->reset_lex(thd); // This changes thd->lex
   DBUG_ASSERT(sphead == thd->lex->sphead);
   DBUG_ASSERT(spcont == thd->lex->spcont);
   sp_instr_jump_if_not *i= new (thd->mem_root)
@@ -5646,7 +5645,6 @@ bool LEX::sp_exit_block(THD *thd, sp_label *lab, Item *when)
                                                 when, thd->lex);
   if (i == NULL ||
       sphead->add_instr(i) ||
-      sphead->restore_lex(thd) ||
       sp_exit_block(thd, lab))
     return true;
   i->backpatch(sphead->instructions(), spcont);
@@ -5712,7 +5710,6 @@ bool LEX::sp_continue_loop(THD *thd, sp_label *lab, Item *when)
   if (!when)
     return sp_continue_loop(thd, lab);
 
-  sphead->reset_lex(thd); // This changes thd->lex
   DBUG_ASSERT(sphead == thd->lex->sphead);
   DBUG_ASSERT(spcont == thd->lex->spcont);
   sp_instr_jump_if_not *i= new (thd->mem_root)
@@ -5721,7 +5718,6 @@ bool LEX::sp_continue_loop(THD *thd, sp_label *lab, Item *when)
                                                 when, thd->lex);
   if (i == NULL ||
       sphead->add_instr(i) ||
-      sphead->restore_lex(thd) ||
       sp_continue_loop(thd, lab))
     return true;
   i->backpatch(sphead->instructions(), spcont);

sql/sql_yacc_ora.yy

@@ -1097,7 +1097,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
         signal_allowed_expr
         simple_target_specification
         condition_number
-        opt_sp_proc_stmt_exit_when_clause
+        reset_lex_expr
 
 %type <item_param> param_marker
 
@@ -2988,33 +2988,56 @@ sp_proc_stmt_return:
           }
         ;
 
-opt_sp_proc_stmt_exit_when_clause:
-          /* Empty */   { $$= NULL; }
-        | WHEN_SYM expr { $$= $2; }
+reset_lex_expr:
+          { Lex->sphead->reset_lex(thd); } expr { $$= $2; }
         ;
 
 sp_proc_stmt_exit:
-          EXIT_SYM opt_sp_proc_stmt_exit_when_clause
+          EXIT_SYM
           {
-            if (Lex->sp_exit_statement(thd, $2))
+            if (Lex->sp_exit_statement(thd, NULL))
               MYSQL_YYABORT;
           }
-        | EXIT_SYM label_ident opt_sp_proc_stmt_exit_when_clause
+        | EXIT_SYM label_ident
           {
-            if (Lex->sp_exit_statement(thd, $2, $3))
+            if (Lex->sp_exit_statement(thd, $2, NULL))
+              MYSQL_YYABORT;
+          }
+        | EXIT_SYM WHEN_SYM reset_lex_expr
+          {
+            if (Lex->sp_exit_statement(thd, $3) ||
+                Lex->sphead->restore_lex(thd))
+              MYSQL_YYABORT;
+          }
+        | EXIT_SYM label_ident WHEN_SYM reset_lex_expr
+          {
+            if (Lex->sp_exit_statement(thd, $2, $4) ||
+                Lex->sphead->restore_lex(thd))
               MYSQL_YYABORT;
           }
         ;
 
 sp_proc_stmt_continue:
-          CONTINUE_SYM opt_sp_proc_stmt_exit_when_clause
+          CONTINUE_SYM
+          {
+            if (Lex->sp_continue_statement(thd, NULL))
+              MYSQL_YYABORT;
+          }
+        | CONTINUE_SYM label_ident
+          {
+            if (Lex->sp_continue_statement(thd, $2, NULL))
+              MYSQL_YYABORT;
+          }
+        | CONTINUE_SYM WHEN_SYM reset_lex_expr
           {
-            if (Lex->sp_continue_statement(thd, $2))
+            if (Lex->sp_continue_statement(thd, $3) ||
+                Lex->sphead->restore_lex(thd))
               MYSQL_YYABORT;
           }
-        | CONTINUE_SYM label_ident opt_sp_proc_stmt_exit_when_clause
+        | CONTINUE_SYM label_ident WHEN_SYM reset_lex_expr
           {
-            if (Lex->sp_continue_statement(thd, $2, $3))
+            if (Lex->sp_continue_statement(thd, $2, $4) ||
+                Lex->sphead->restore_lex(thd))
               MYSQL_YYABORT;
           }
         ;