Bug#22312 Syntax error in expression with INTERVAL()

Parser rejects valid INTERVAL() expressions when associated with
arithmetic operators. The problem is the way in which the expression
and interval grammar rules were organized caused shift/reduce conflicts.

The solution is to tweak the interval rules to avoid shift/reduce
conflicts by removing the broken interval_expr rule and explicitly
specify it's content where necessary.

Original fix by Davi Arnaut, revised and improved rules by Marc Alff


mysql-test/r/parser.result:
  Add test case result for Bug#22312
mysql-test/t/parser.test:
  Add test case for Bug#22312
sql/sql_yacc.yy:
  Resolve shift/reduce conflicts by reorganizing the interval
  expression rules.

1 files changed, 30 insertions, 27 deletions

diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 5de142ca83a..80e354aef98 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -508,10 +508,10 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 
 %pure_parser                                    /* We have threads */
 /*
-  Currently there are 280 shift/reduce conflicts.
+  Currently there are 177 shift/reduce conflicts.
   We should not introduce new conflicts any more.
 */
-%expect 280
+%expect 177
 
 /*
    Comments for TOKENS.
@@ -1157,7 +1157,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
         variable variable_aux bool_pri
         predicate bit_expr
         table_wild simple_expr udf_expr
-        expr_or_default set_expr_or_default interval_expr
+        expr_or_default set_expr_or_default
         param_marker geometry_function
         signed_literal now_or_signed_literal opt_escape
         sp_opt_default
@@ -6569,10 +6569,10 @@ bit_expr:
           { $$= new Item_func_plus($1,$3); }
         | bit_expr '-' bit_expr %prec '-'
           { $$= new Item_func_minus($1,$3); }
-        | bit_expr '+' interval_expr interval %prec '+'
-          { $$= new Item_date_add_interval($1,$3,$4,0); }
-        | bit_expr '-' interval_expr interval %prec '-'
-          { $$= new Item_date_add_interval($1,$3,$4,1); }
+        | bit_expr '+' INTERVAL_SYM expr interval %prec '+'
+          { $$= new Item_date_add_interval($1,$4,$5,0); }
+        | bit_expr '-' INTERVAL_SYM expr interval %prec '-'
+          { $$= new Item_date_add_interval($1,$4,$5,1); }
         | bit_expr '*' bit_expr %prec '*'
           { $$= new Item_func_mul($1,$3); }
         | bit_expr '/' bit_expr %prec '/'
@@ -6622,11 +6622,6 @@ all_or_any:
         | ANY_SYM { $$ = 0; }
         ;
 
-interval_expr:
-          INTERVAL_SYM expr %prec INTERVAL_SYM
-          { $$=$2; }
-        ;
-
 simple_expr:
           simple_ident
         | function_call_keyword
@@ -6722,18 +6717,9 @@ simple_expr:
             $$= new (YYTHD->mem_root) Item_insert_value(Lex->current_context(),
                                                         $3);
           }
-        | interval_expr interval '+' expr
+        | INTERVAL_SYM expr interval '+' expr %prec INTERVAL_SYM
           /* we cannot put interval before - */
-          { $$= new (YYTHD->mem_root) Item_date_add_interval($4,$1,$2,0); }
-        | interval_expr
-          {
-            if ($1->type() != Item::ROW_ITEM)
-            {
-              my_parse_error(ER(ER_SYNTAX_ERROR));
-              MYSQL_YYABORT;
-            }
-            $$= new (YYTHD->mem_root) Item_func_interval((Item_row *)$1);
-          }
+          { $$= new (YYTHD->mem_root) Item_date_add_interval($5,$2,$3,0); }
         ;
 
 /*
@@ -6761,6 +6747,23 @@ function_call_keyword:
           { $$= new (YYTHD->mem_root) Item_func_hour($3); }
         | INSERT '(' expr ',' expr ',' expr ',' expr ')'
           { $$= new (YYTHD->mem_root) Item_func_insert($3,$5,$7,$9); }
+        | INTERVAL_SYM '(' expr ',' expr ')' %prec INTERVAL_SYM
+          {
+            THD *thd= YYTHD;
+            List<Item> *list= new (thd->mem_root) List<Item>;
+            list->push_front($5);
+            list->push_front($3);
+            Item_row *item= new (thd->mem_root) Item_row(*list);
+            $$= new (thd->mem_root) Item_func_interval(item);
+          }
+        | INTERVAL_SYM '(' expr ',' expr ',' expr_list ')' %prec INTERVAL_SYM
+          {
+            THD *thd= YYTHD;
+            $7->push_front($5);
+            $7->push_front($3);
+            Item_row *item= new (thd->mem_root) Item_row(*$7);
+            $$= new (thd->mem_root) Item_func_interval(item);
+          }
         | LEFT '(' expr ',' expr ')'
           { $$= new (YYTHD->mem_root) Item_func_left($3,$5); }
         | MINUTE_SYM '(' expr ')'
@@ -6838,10 +6841,10 @@ function_call_nonkeyword:
             $$= new (YYTHD->mem_root) Item_func_curtime_local($3);
             Lex->safe_to_cache_query=0;
           }
-        | DATE_ADD_INTERVAL '(' expr ',' interval_expr interval ')'
-          { $$= new (YYTHD->mem_root) Item_date_add_interval($3,$5,$6,0); }
-        | DATE_SUB_INTERVAL '(' expr ',' interval_expr interval ')'
-          { $$= new (YYTHD->mem_root) Item_date_add_interval($3,$5,$6,1); }
+        | DATE_ADD_INTERVAL '(' expr ',' INTERVAL_SYM expr interval ')' %prec INTERVAL_SYM
+          { $$= new (YYTHD->mem_root) Item_date_add_interval($3,$6,$7,0); }
+        | DATE_SUB_INTERVAL '(' expr ',' INTERVAL_SYM expr interval ')' %prec INTERVAL_SYM
+          { $$= new (YYTHD->mem_root) Item_date_add_interval($3,$6,$7,1); }
         | EXTRACT_SYM '(' interval FROM expr ')'
           { $$=new (YYTHD->mem_root) Item_extract( $3, $5); }
         | GET_FORMAT '(' date_time_type  ',' expr ')'