Fixes and test cases for Bug#729758, Bug#729879

A fix and a test case for

https://bugs.launchpad.net/tarantool/+bug/729758
"SELECT fails with a disjunct and small LIMIT"

and

https://bugs.launchpad.net/tarantool/+bug/729879
"Zero limit is treated the same as no limit"

These were simple coding bugs in SELECT main loop.

mod/silverbox/box.c

@@ -558,6 +558,11 @@ process_select(struct box_txn *txn, u32 limit, u32 offset, struct tbuf *data)
 
 	if (txn->index->type == TREE) {
 		for (u32 i = 0; i < count; i++) {
+
+			/* End the loop if reached the limit. */
+			if (limit == *found)
+				goto end;
+
 			u32 key_len = read_u32(data);
 			void *key = read_field(data);
 
@@ -578,17 +583,19 @@ process_select(struct box_txn *txn, u32 limit, u32 offset, struct tbuf *data)
 					continue;
 				}
 
-				(*found)++;
 				tuple_add_iov(txn, tuple);
 
-				if (--limit == 0)
+				if (limit == ++(*found))
 					break;
 			}
-			if (limit == 0)
-				break;
 		}
 	} else {
 		for (u32 i = 0; i < count; i++) {
+
+			/* End the loop if reached the limit. */
+			if (limit == *found)
+				goto end;
+
 			u32 key_len = read_u32(data);
 			if (key_len != 1)
 				box_raise(ERR_CODE_ILLEGAL_PARAMS,
@@ -603,17 +610,15 @@ process_select(struct box_txn *txn, u32 limit, u32 offset, struct tbuf *data)
 				continue;
 			}
 
-			(*found)++;
 			tuple_add_iov(txn, tuple);
-
-			if (--limit == 0)
-				break;
+			(*found)++;
 		}
 	}
 
 	if (data->len != 0)
 		box_raise(ERR_CODE_ILLEGAL_PARAMS, "can't unpack request");
 
+end:
 	return ERR_CODE_OK;
 }
 

test/box_big/sql.result

+
+A test case for Bug#729758
+"SELECT fails with a disjunct and small LIMIT"
+https://bugs.launchpad.net/tarantool/+bug/729758
+
 insert into t0 values ('Doe', 'Richard')
 Insert OK, 1 row affected
 insert into t0 values ('Roe', 'Richard')
@@ -15,4 +20,32 @@ Insert OK, 1 row affected
 insert into t0 values ('Callaghan', 'Tomas')
 Insert OK, 1 row affected
 select * from t0 where k1='Richard' or k1='Tomas' or k1='Tomas' limit 5
-An error occurred: ERR_CODE_ILLEGAL_PARAMS, 'Illegal parameters'
+Found 5 tuples:
+['Doe', 'Richard']
+['Roe', 'Richard']
+['Woe', 'Richard']
+['Major', 'Tomas']
+['Kytes', 'Tomas']
+
+A test case for Bug#729879
+"Zero limit is treated the same as no limit"
+https://bugs.launchpad.net/tarantool/+bug/729879
+
+select * from t0 where k1='Richard' or k1='Tomas' limit 0
+No match
+delete from t0 where k0='Doe'
+Delete OK, 1 row affected
+delete from t0 where k0='Roe'
+Delete OK, 1 row affected
+delete from t0 where k0='Woe'
+Delete OK, 1 row affected
+delete from t0 where k0='Major'
+Delete OK, 1 row affected
+delete from t0 where k0='Kytes'
+Delete OK, 1 row affected
+delete from t0 where k0='Stiles'
+Delete OK, 1 row affected
+delete from t0 where k0='Wales'
+Delete OK, 1 row affected
+delete from t0 where k0='Callaghan'
+Delete OK, 1 row affected

test/box_big/sql.test

 # encoding: tarantool
+#
+print """
+A test case for Bug#729758
+"SELECT fails with a disjunct and small LIMIT"
+https://bugs.launchpad.net/tarantool/+bug/729758
+"""
 
 exec sql "insert into t0 values ('Doe', 'Richard')"
 exec sql "insert into t0 values ('Roe', 'Richard')"
@@ -8,7 +14,22 @@ exec sql "insert into t0 values ('Kytes', 'Tomas')"
 exec sql "insert into t0 values ('Stiles', 'Tomas')"
 exec sql "insert into t0 values ('Wales', 'Tomas')"
 exec sql "insert into t0 values ('Callaghan', 'Tomas')"
-# xxx: bug
 exec sql "select * from t0 where k1='Richard' or k1='Tomas' or k1='Tomas' limit 5"
 
+print """
+A test case for Bug#729879
+"Zero limit is treated the same as no limit"
+https://bugs.launchpad.net/tarantool/+bug/729879
+"""
+exec sql "select * from t0 where k1='Richard' or k1='Tomas' limit 0"
+
+# Cleanup
+exec sql "delete from t0 where k0='Doe'"
+exec sql "delete from t0 where k0='Roe'"
+exec sql "delete from t0 where k0='Woe'"
+exec sql "delete from t0 where k0='Major'"
+exec sql "delete from t0 where k0='Kytes'"
+exec sql "delete from t0 where k0='Stiles'"
+exec sql "delete from t0 where k0='Wales'"
+exec sql "delete from t0 where k0='Callaghan'"
 # vim: syntax=python