Fixed bug mdev-5015.

The patch for mdev-4355 had a defect: the cached values for bitmaps of
used tables were not updated when processing degenerate OR formulas.

mysql-test/r/func_group.result

@@ -2124,4 +2124,17 @@ select z from (select count(*) as z from t1) v group by 1;
 z
 4
 drop table t1;
+CREATE TABLE t1 (i1 int, INDEX(i1));
+INSERT INTO t1 VALUES (9),(8);
+CREATE TABLE t2 (i2 int);
+INSERT INTO t2 VALUES (8),(4);
+CREATE TABLE t3 (i3 int, INDEX(i3));
+INSERT INTO t3 VALUES (9),(8);
+SELECT MAX(t3.i3) FROM t3, t2, t1 WHERE t1.i1 = t2.i2 AND ( 0 OR t3.i3 = t2.i2 );
+MAX(t3.i3)
+8
+SELECT MAX(t3.i3) FROM t3, t2, t1 WHERE t1.i1 = t2.i2 AND  t3.i3 = t2.i2;
+MAX(t3.i3)
+8
+DROP TABLE  t1,t2,t3;
 # end of 5.3 tests

mysql-test/t/func_group.test

@@ -1403,4 +1403,24 @@ select z from (select count(*) as z from t1) v;
 select z from (select count(*) as z from t1) v group by 1; 
 drop table t1;
 
+#
+# Bug mdev-5015: Degenerate OR condition in an aggregated join
+#
+
+CREATE TABLE t1 (i1 int, INDEX(i1));
+INSERT INTO t1 VALUES (9),(8);
+
+CREATE TABLE t2 (i2 int);
+INSERT INTO t2 VALUES (8),(4);
+
+
+CREATE TABLE t3 (i3 int, INDEX(i3));
+INSERT INTO t3 VALUES (9),(8);
+
+SELECT MAX(t3.i3) FROM t3, t2, t1 WHERE t1.i1 = t2.i2 AND ( 0 OR t3.i3 = t2.i2 );
+
+SELECT MAX(t3.i3) FROM t3, t2, t1 WHERE t1.i1 = t2.i2 AND  t3.i3 = t2.i2;
+
+DROP TABLE  t1,t2,t3;
+
 --echo # end of 5.3 tests

sql/sql_select.cc

@@ -13506,6 +13506,7 @@ remove_eq_conds(THD *thd, COND *cond, Item::cond_result *cond_value)
         if (!(cond= remove_eq_conds(thd, cond, cond_value)))
           return cond;
       } 
+      should_fix_fields= 1;
     }
     if (should_fix_fields)
       cond->update_used_tables();