MDEV-10411 Providing compatibility for basic PL/SQL constructs

Part 9: EXCEPTION handlers

- Adding exception handler syntax:
  WHEN exception_name THEN statement
- Adding EXCEPTION section intoi the top BEGIN..END SP block.
  Note, currently EXCEPTION goes in the beginning of the top BEGIN..END
  SP block.

TODO:
- add EXCEPTION section into inner blocks
- move EXCEPTION to the end of the block

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

@@ -350,3 +350,23 @@ i
 4
 i
 3
+# Testing exceptions
+CREATE TABLE t1 (c1 INT);
+CREATE PROCEDURE sp1 (p1 IN VARCHAR2(20), p2 OUT VARCHAR2(30))
+IS
+v1 INT;
+BEGIN
+EXCEPTION WHEN NOT FOUND THEN
+BEGIN
+p2 := 'def';
+END;
+SELECT c1 INTO v1 FROM t1;
+p2 := p1;
+END;
+/
+CALL sp1('abc', @a);
+SELECT @a;
+@a
+def
+DROP PROCEDURE sp1;
+DROP TABLE t1;

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

@@ -377,3 +377,31 @@ BEGIN NOT ATOMIC
 END
 /
 DELIMITER ;/
+
+
+--echo # Testing exceptions
+
+CREATE TABLE t1 (c1 INT);
+
+DELIMITER /;
+
+CREATE PROCEDURE sp1 (p1 IN VARCHAR2(20), p2 OUT VARCHAR2(30))
+IS
+  v1 INT;
+BEGIN
+  EXCEPTION WHEN NOT FOUND THEN
+  BEGIN
+    p2 := 'def';
+  END;
+  SELECT c1 INTO v1 FROM t1;
+  p2 := p1;
+END;
+/
+
+DELIMITER ;/
+
+CALL sp1('abc', @a);
+SELECT @a;
+
+DROP PROCEDURE sp1;
+DROP TABLE t1;

sql/lex.h

@@ -222,6 +222,7 @@ static SYMBOL symbols[] = {
   { "EXCHANGE",         SYM(EXCHANGE_SYM)},
   { "EXCLUDE",          SYM(EXCLUDE_SYM)},
   { "EXECUTE",		SYM(EXECUTE_SYM)},
+  { "EXCEPTION",	SYM(EXCEPTION_SYM)},
   { "EXISTS",		SYM(EXISTS)},
   { "EXIT",             SYM(EXIT_SYM)},
   { "EXPANSION",	SYM(EXPANSION_SYM)},

sql/sql_yacc.yy

@@ -1150,6 +1150,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 %token  EXCEPT_SYM                    /* SQL-2003-R */
 %token  EXCLUDE_SYM                   /* SQL-2011-N */
 %token  EXECUTE_SYM                   /* SQL-2003-R */
+%token  EXCEPTION_SYM                 /* SQL-2003-N */
 %token  EXISTS                        /* SQL-2003-R */
 %token  EXIT_SYM
 %token  EXPANSION_SYM
@@ -14471,6 +14472,7 @@ keyword_sp:
         | EVENT_SYM                {}
         | EVENTS_SYM               {}
         | EVERY_SYM                {}
+        | EXCEPTION_SYM            {}
         | EXCHANGE_SYM             {}
         | EXPANSION_SYM            {}
         | EXPORT_SYM               {}

sql/sql_yacc_ora.yy

@@ -525,6 +525,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 %token  EXCEPT_SYM                    /* SQL-2003-R */
 %token  EXCLUDE_SYM                   /* SQL-2011-N */
 %token  EXECUTE_SYM                   /* SQL-2003-R */
+%token  EXCEPTION_SYM                 /* SQL-2003-N */
 %token  EXISTS                        /* SQL-2003-R */
 %token  EXIT_SYM
 %token  EXPANSION_SYM
@@ -1330,6 +1331,7 @@ END_OF_INPUT
 %type <num>  sp_decl_idents sp_handler_type sp_hcond_list
 %type <spcondvalue> sp_cond sp_hcond sqlstate signal_value opt_signal_value
 %type <spblock> sp_decl_body sp_decl_body_list opt_sp_decl_body_list
+%type <num> opt_exception_clause exception_handlers
 %type <lex> sp_cursor_stmt
 %type <spname> sp_name
 %type <spvar> sp_param_name sp_param_name_and_type
@@ -2523,7 +2525,7 @@ sp_hcond:
             if ($$ == NULL)
               MYSQL_YYABORT;
           }
-        | SQLEXCEPTION_SYM /* All other SQLSTATEs */
+        | OTHERS_SYM /* All other SQLSTATEs */
           {
             $$= new (thd->mem_root) sp_condition_value(sp_condition_value::EXCEPTION);
             if ($$ == NULL)
@@ -3432,6 +3434,10 @@ sp_body:
           }
           opt_sp_decl_body_list
           BEGIN_SYM
+          opt_exception_clause
+          {
+            $2.hndlrs+= $4;
+          }
           sp_proc_stmts
           END
           {
@@ -3455,6 +3461,31 @@ sp_unlabeled_block_not_atomic:
           }
         ;
 
+opt_exception_clause:
+          /* Empty */                      { $$= 0; }
+        | EXCEPTION_SYM exception_handlers { $$= $2; }
+        ;
+
+exception_handlers:
+           exception_handler ';'                    { $$= 1; }
+         | exception_handlers exception_handler ';' { $$= $1 + 1; }
+        ;
+
+exception_handler:
+          WHEN_SYM
+          {
+            if (Lex->sp_handler_declaration_init(thd, sp_handler::EXIT))
+              MYSQL_YYABORT;
+          }
+          sp_hcond_list
+          THEN_SYM
+          sp_proc_stmt
+          {
+            if (Lex->sp_handler_declaration_finalize(thd, sp_handler::EXIT))
+              MYSQL_YYABORT;
+          }
+        ;
+
 loop_body:
           sp_proc_stmts1 END LOOP_SYM
           {