Bug#48459: valgrind errors with query using 'Range checked

for each record'

There was an error in an internal structure in the range
optimizer (SEL_ARG). Bad design causes parts of a data
structure not to be initialized when it is in a certain
state. All client code must check that this state is not
present before trying to access the structure's data. Fixed
by

- Checking the state before trying to access data (in
several places, most of which not covered by test case.)

- Copying the keypart id when cloning SEL_ARGs

mysql-test/r/range.result

@@ -1604,6 +1604,39 @@ str_to_date('', '%Y-%m-%d')
 0000-00-00
 DROP TABLE t1, t2;
 #
+# Bug#48459: valgrind errors with query using 'Range checked for each 
+# record'
+#
+CREATE TABLE t1 (
+a INT,
+b CHAR(2),
+c INT,
+d INT,
+KEY ( c ),
+KEY ( d, a, b ( 2 ) ),
+KEY ( b ( 1 ) )
+);
+INSERT INTO t1 VALUES ( NULL, 'a', 1, 2 ), ( NULL, 'a', 1, 2 ),
+( 1,    'a', 1, 2 ), ( 1,    'a', 1, 2 );
+CREATE TABLE t2 (
+a INT,
+c INT,
+e INT,
+KEY ( e )
+);
+INSERT INTO t2 VALUES ( 1, 1, NULL ), ( 1, 1, NULL );
+# Should not give Valgrind warnings
+SELECT 1
+FROM t1, t2
+WHERE t1.d <> '1' AND t1.b > '1'
+AND t1.a = t2.a AND t1.c = t2.c;
+1
+1
+1
+1
+1
+DROP TABLE t1, t2;
+#
 # Bug #48665: sql-bench's insert test fails due to wrong result
 #
 CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a));