fix #182. Don't segfault on queries with invalid limit clause.

CHANGELOG.md

@@ -180,6 +180,7 @@
 - [Issue #145](https://github.com/influxdb/influxdb/issues/145). Server fails to join cluster if all starting at same time.
 - [Issue #176](https://github.com/influxdb/influxdb/issues/176). Drop database should take effect on all nodes
 - [Issue #180](https://github.com/influxdb/influxdb/issues/180). Column names not returned when running multi-node cluster and writing more than one point.
+- [Issue #182](https://github.com/influxdb/influxdb/issues/182). Queries with invalid limit clause crash the server
 
 ### Deprecated
 

src/parser/frees.c

@@ -46,6 +46,9 @@ free_value_array(value_array *array)
 void
 free_groupby_clause(groupby_clause *g)
 {
+  if (!g)
+    return;
+
   free_value_array(g->elems);
   if (g->fill_function) {
     free_value(g->fill_function);

src/parser/parser_test.go

@@ -533,6 +533,11 @@ func (self *QueryParserSuite) TestParseWhereClauseParentheses(c *C) {
 	c.Assert(third.Name, Equals, ">")
 }
 
+func (self *QueryParserSuite) TestParseSelectWithInvalidLimit(c *C) {
+	_, err := ParseSelectQuery("select value from t limit;")
+	c.Assert(err, NotNil)
+}
+
 func (self *QueryParserSuite) TestParseSelectWithOrderByAndLimit(c *C) {
 	q, err := ParseSelectQuery("select value from t order asc limit 10;")
 	c.Assert(err, IsNil)

src/parser/test_memory_leaks.sh

@@ -42,6 +42,9 @@ int main(int argc, char **argv) {
   q = parse_query("drop series foobar");
   close_query(&q);
 
+  q = parse_query("select * from foobar limit");
+  close_query(&q);
+
   return 0;
 }
 EOF