From 493c7d34cb2c5c0bc8c495d1dd7b2394c62036ad Mon Sep 17 00:00:00 2001
From: Sergei Golubchik <serg@mariadb.org>
Date: Mon, 23 Nov 2020 14:10:44 +0100
Subject: [PATCH] MDEV-24194 View definition corruption

fix parsing of "1 IS NULL = 2"
---
 mysql-test/r/precedence.result |  4 ++++
 mysql-test/t/precedence.test   |  3 +++
 sql/sql_yacc.yy                | 16 ++++++----------
 3 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/mysql-test/r/precedence.result b/mysql-test/r/precedence.result
index 986af63134688..65c32ba2b04f9 100644
--- a/mysql-test/r/precedence.result
+++ b/mysql-test/r/precedence.result
@@ -8017,4 +8017,8 @@ create or replace view v1 as select 1 IS TRUE IS FALSE, 2 IS FALSE IS UNKNOWN, 3
 Select view_definition from information_schema.views where table_schema='test' and table_name='v1';
 view_definition
 select 1 is true is false AS `1 IS TRUE IS FALSE`,/*always not null*/ 1 is null AS `2 IS FALSE IS UNKNOWN`,/*always not null*/ 1 is null AS `3 IS UNKNOWN IS NULL`,/*always not null*/ 1 is null is true AS `4 IS NULL IS TRUE`
+create or replace view v1 as select 2 IS TRUE = 3, 2 IS FALSE = 3, 2 IS UNKNOWN = 3, 2 IS NULL = 3, ISNULL(2) = 1;
+Select view_definition from information_schema.views where table_schema='test' and table_name='v1';
+view_definition
+select 2 is true = 3 AS `2 IS TRUE = 3`,2 is false = 3 AS `2 IS FALSE = 3`,/*always not null*/ 1 is null = 3 AS `2 IS UNKNOWN = 3`,/*always not null*/ 1 is null = 3 AS `2 IS NULL = 3`,/*always not null*/ 1 is null = 1 AS `ISNULL(2) = 1`
 drop view v1;
diff --git a/mysql-test/t/precedence.test b/mysql-test/t/precedence.test
index ad367c23603de..cd7cee4f911da 100644
--- a/mysql-test/t/precedence.test
+++ b/mysql-test/t/precedence.test
@@ -4785,4 +4785,7 @@ Select view_definition from information_schema.views where table_schema='test' a
 create or replace view v1 as select 1 IS TRUE IS FALSE, 2 IS FALSE IS UNKNOWN, 3 IS UNKNOWN IS NULL, 4 IS NULL IS TRUE;
 Select view_definition from information_schema.views where table_schema='test' and table_name='v1';
 
+create or replace view v1 as select 2 IS TRUE = 3, 2 IS FALSE = 3, 2 IS UNKNOWN = 3, 2 IS NULL = 3, ISNULL(2) = 1;
+Select view_definition from information_schema.views where table_schema='test' and table_name='v1';
+
 drop view v1;
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 2eabc4f0a6dbb..1f37296842c04 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -1030,10 +1030,10 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 %parse-param { THD *thd }
 %lex-param { THD *thd }
 /*
-  Currently there are 105 shift/reduce conflicts.
+  Currently there are 98 shift/reduce conflicts.
   We should not introduce new conflicts any more.
 */
-%expect 105
+%expect 98
 
 /*
    Comments for TOKENS.
@@ -1836,7 +1836,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 %type <item>
         literal text_literal insert_ident order_ident temporal_literal
         simple_ident expr opt_expr opt_else sum_expr in_sum_expr
-        variable variable_aux bool_pri
+        variable variable_aux
         predicate bit_expr parenthesized_expr
         table_wild simple_expr column_default_non_parenthesized_expr udf_expr
         expr_or_default set_expr_or_default
@@ -8972,23 +8972,19 @@ expr:
             if ($$ == NULL)
               MYSQL_YYABORT;
           }
-        | bool_pri
-        ;
-
-bool_pri:
-          bool_pri EQUAL_SYM predicate %prec EQUAL_SYM
+        | expr EQUAL_SYM predicate %prec EQUAL_SYM
           {
             $$= new (thd->mem_root) Item_func_equal(thd, $1, $3);
             if ($$ == NULL)
               MYSQL_YYABORT;
           }
-        | bool_pri comp_op predicate %prec '='
+        | expr comp_op predicate %prec '='
           {
             $$= (*$2)(0)->create(thd, $1, $3);
             if ($$ == NULL)
               MYSQL_YYABORT;
           }
-        | bool_pri comp_op all_or_any '(' subselect ')' %prec '='
+        | expr comp_op all_or_any '(' subselect ')' %prec '='
           {
             $$= all_any_subquery_creator(thd, $1, $2, $3, $5);
             if ($$ == NULL)