MDEV-10228: Delete missing rows with OR conditions

Fix get_quick_keys(): When building range tree from a condition
in form

  keypart1=const AND (keypart2 < 0 OR keypart2>=0)

the SEL_ARG for keypart2 represents an interval (-inf, +inf).
However, the logic that sets UNIQUE_RANGE flag fails to recognize
this, and sets UNIQUE_RANGE flag if (keypart1, keypart2) covered
a unique key.
As a result, range access executor assumes the interval can have
at most one row and only reads the first row from it.

mysql-test/r/range.result

@@ -2113,3 +2113,34 @@ a	b
 0	0
 1	1
 drop table t2;
+#
+# MDEV-10228: Delete missing rows with OR conditions
+#  (The example uses UPDATE, because UPDATE allows to use index hints
+#   and so it's possible to make an example that works with any storage
+#   engine)
+#
+CREATE TABLE t1 (
+key1varchar varchar(14) NOT NULL,
+key2int int(11) NOT NULL DEFAULT '0',
+col1 int,
+PRIMARY KEY (key1varchar,key2int),
+KEY key1varchar (key1varchar),
+KEY key2int (key2int)
+) DEFAULT CHARSET=utf8;
+insert into t1 values 
+('value1',0, 0),
+('value1',1, 0),
+('value1',1000685, 0),
+('value1',1003560, 0),
+('value1',1004807, 0);
+update t1 force index (PRIMARY) set col1=12345
+where (key1varchar='value1' AND (key2int <=1 OR  key2int > 1));
+# The following must show col1=12345 for all rows:
+select * from t1;
+key1varchar	key2int	col1
+value1	0	12345
+value1	1	12345
+value1	1000685	12345
+value1	1003560	12345
+value1	1004807	12345
+drop table t1;

mysql-test/t/range.test

@@ -1689,3 +1689,32 @@ insert into t2 values (0, 0, 0, 0), (1, 1, 1, 1);
 analyze table t2;
 select a, b from t2 where (a, b) in ((0, 0), (1, 1));
 drop table t2;
+
+--echo #
+--echo # MDEV-10228: Delete missing rows with OR conditions
+--echo #  (The example uses UPDATE, because UPDATE allows to use index hints
+--echo #   and so it's possible to make an example that works with any storage
+--echo #   engine)
+--echo #
+
+CREATE TABLE t1 (
+  key1varchar varchar(14) NOT NULL,
+  key2int int(11) NOT NULL DEFAULT '0',
+  col1 int,
+  PRIMARY KEY (key1varchar,key2int),
+  KEY key1varchar (key1varchar),
+  KEY key2int (key2int)
+) DEFAULT CHARSET=utf8;
+
+insert into t1 values 
+  ('value1',0, 0),
+  ('value1',1, 0),
+  ('value1',1000685, 0),
+  ('value1',1003560, 0),
+  ('value1',1004807, 0);
+
+update t1 force index (PRIMARY) set col1=12345
+where (key1varchar='value1' AND (key2int <=1 OR  key2int > 1));
+--echo # The following must show col1=12345 for all rows:
+select * from t1;
+drop table t1;

sql/opt_range.cc

@@ -10409,8 +10409,10 @@ get_quick_keys(PARAM *param,QUICK_RANGE_SELECT *quick,KEY_PART *key,
       KEY *table_key=quick->head->key_info+quick->index;
       flag=EQ_RANGE;
       if ((table_key->flags & HA_NOSAME) &&
+          min_part == key_tree->part &&
           key_tree->part == table_key->key_parts-1)
       {
+        DBUG_ASSERT(min_part == max_part);
         if ((table_key->flags & HA_NULL_PART_KEY) &&
             null_part_in_key(key,
                              param->min_key,