Fixed bug with UPDATE/DELETE on UNIQUE key which could be NULL

Docs/manual.texi:
  Updated replication section
mysql-test/r/null_key.result:
  Added test UPDATE/DELETE with IS NULL on unique key
mysql-test/t/null_key.test:
  Added test UPDATE/DELETE with IS NULL on unique key
mysys/Makefile.am:
  Removed -f from $CP as this is not portable
  Fixed rule for testhash
sql/field.cc:
  Safety fix
sql/opt_range.cc:
  Fixed bug with UPDATE/DELETE on UNIQUE key which could be NULL
sql/opt_range.h:
  Fixed bug with UPDATE/DELETE on UNIQUE key which could be NULL

2 files changed, 74 insertions, 0 deletions

diff --git a/mysql-test/r/null_key.result b/mysql-test/r/null_key.result
index 98c43b20b01..ead1dc29326 100644
--- a/mysql-test/r/null_key.result
+++ b/mysql-test/r/null_key.result
@@ -92,3 +92,31 @@ NULL	9	0
 NULL	9	0
 a	b	c
 6	6	0
+table	type	possible_keys	key	key_len	ref	rows	Extra
+t1	ref	idx1	idx1	5	const	1	where used
+table	type	possible_keys	key	key_len	ref	rows	Extra
+t1	const	idx1	idx1	5	const	1	
+id
+101
+102
+105
+106
+109
+110
+id
+101
+102
+105
+106
+109
+110
+id	uniq_id
+3	1
+4	2
+7	3
+8	4
+id	uniq_id
+3	1
+4	2
+7	3
+8	4
diff --git a/mysql-test/t/null_key.test b/mysql-test/t/null_key.test
index 759f4a432da..e5d8fc59e4f 100644
--- a/mysql-test/t/null_key.test
+++ b/mysql-test/t/null_key.test
@@ -45,3 +45,49 @@ select * from t1 where (a is null or a = 7) and b=7 and c=0;
 select * from t1 where a is null and b=9 or a is null and b=7 limit 3;
 select * from t1 where b like "6%";
 drop table t1;
+
+
+#
+# The following failed for Matt Loschert
+#
+
+DROP TABLE IF EXISTS t1,t2;
+CREATE TABLE t1 (
+  id int(10) unsigned NOT NULL auto_increment,
+  uniq_id int(10) unsigned default NULL,
+  PRIMARY KEY  (id),
+  UNIQUE KEY idx1 (uniq_id)
+) TYPE=MyISAM;
+
+CREATE TABLE t2 (
+  id int(10) unsigned NOT NULL auto_increment,
+  uniq_id int(10) unsigned default NULL,
+  PRIMARY KEY  (id)
+) TYPE=MyISAM;
+
+INSERT INTO t1 VALUES (1,NULL),(2,NULL),(3,1),(4,2),(5,NULL),(6,NULL),(7,3),(8,4),(9,NULL),(10,NULL);
+INSERT INTO t2 VALUES (1,NULL),(2,NULL),(3,1),(4,2),(5,NULL),(6,NULL),(7,3),(8,4),(9,NULL),(10,NULL);
+
+#
+# Check IS NULL optimization
+#
+explain select id from t1 where uniq_id is null;
+explain select id from t1 where uniq_id =1;
+#
+# Check updates
+#
+UPDATE t1 SET id=id+100 where uniq_id is null;
+UPDATE t2 SET id=id+100 where uniq_id is null;
+select id from t1 where uniq_id is null;
+select id from t2 where uniq_id is null;
+#
+# Delete all records from each table where the uniq_id field is null
+#
+DELETE FROM t1 WHERE uniq_id IS NULL;
+DELETE FROM t2 WHERE uniq_id IS NULL;
+#
+# Select what is left -- notice the difference
+#
+SELECT * FROM t1 ORDER BY uniq_id, id;
+SELECT * FROM t2 ORDER BY uniq_id, id;
+DROP table t1,t2;