Use net.{Join,Split}HostPort for proper ipv6 handling

conn.go

@@ -362,7 +362,7 @@ func network(o values) (string, string) {
 		return "unix", sockPath
 	}
 
-	return "tcp", host + ":" + o.Get("port")
+	return "tcp", net.JoinHostPort(host, o.Get("port"))
 }
 
 type values map[string]string

url.go

@@ -2,6 +2,7 @@ package pq
 
 import (
 	"fmt"
+	"net"
 	nurl "net/url"
 	"sort"
 	"strings"
@@ -54,12 +55,11 @@ func ParseURL(url string) (string, error) {
 		accrue("password", v)
 	}
 
-	i := strings.Index(u.Host, ":")
-	if i < 0 {
+	if host, port, err := net.SplitHostPort(u.Host); err != nil {
 		accrue("host", u.Host)
 	} else {
-		accrue("host", u.Host[:i])
-		accrue("port", u.Host[i+1:])
+		accrue("host", host)
+		accrue("port", port)
 	}
 
 	if u.Path != "" {

url_test.go

@@ -16,6 +16,18 @@ func TestSimpleParseURL(t *testing.T) {
 	}
 }
 
+func TestIPv6LoopbackParseURL(t *testing.T) {
+	expected := "host=::1 port=1234"
+	str, err := ParseURL("postgres://[::1]:1234")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if str != expected {
+		t.Fatalf("unexpected result from ParseURL:\n+ %v\n- %v", str, expected)
+	}
+}
+
 func TestFullParseURL(t *testing.T) {
 	expected := `dbname=database host=hostname.remote password=top\ secret port=1234 user=username`
 	str, err := ParseURL("postgres://username:top%20secret@hostname.remote:1234/database")