Fix network listener address comparison, fixes #1258 (#1273)

* Fix issue #1258

* address comments

* add a test

* address comments 2

caddy.go

@@ -232,7 +232,7 @@ func HasListenerWithAddress(addr string) bool {
 func listenerAddrEqual(ln net.Listener, addr string) bool {
 	lnAddr := ln.Addr().String()
 	hostname, port, err := net.SplitHostPort(addr)
-	if err != nil || hostname != "" {
+	if err != nil {
 		return lnAddr == addr
 	}
 	if lnAddr == net.JoinHostPort("::", port) {
@@ -241,7 +241,7 @@ func listenerAddrEqual(ln net.Listener, addr string) bool {
 	if lnAddr == net.JoinHostPort("0.0.0.0", port) {
 		return true
 	}
-	return false
+	return hostname != "" && lnAddr == addr
 }
 
 // TCPServer is a type that can listen and serve connections.

caddy_test.go

 package caddy
 
-import "testing"
+import (
+	"net"
+	"strconv"
+	"testing"
+)
 
 /*
 // TODO
@@ -56,3 +60,39 @@ func TestIsLoopback(t *testing.T) {
 		}
 	}
 }
+
+func TestListenerAddrEqual(t *testing.T) {
+	ln1, err := net.Listen("tcp", "[::]:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer ln1.Close()
+
+	ln1port := strconv.Itoa(ln1.Addr().(*net.TCPAddr).Port)
+
+	ln2, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer ln2.Close()
+
+	ln2port := strconv.Itoa(ln2.Addr().(*net.TCPAddr).Port)
+
+	for i, test := range []struct {
+		ln     net.Listener
+		addr   string
+		expect bool
+	}{
+		{ln1, ":1234", false},
+		{ln1, "0.0.0.0:1234", false},
+		{ln1, ":" + ln1port + "", true},
+		{ln1, "0.0.0.0:" + ln1port + "", true},
+		{ln2, "127.0.0.1:1234", false},
+		{ln2, ":" + ln2port + "", false},
+		{ln2, "127.0.0.1:" + ln2port + "", true},
+	} {
+		if got, want := listenerAddrEqual(test.ln, test.addr), test.expect; got != want {
+			t.Errorf("Test %d (%s == %s): expected %v but was %v", i, test.addr, test.ln.Addr().String(), want, got)
+		}
+	}
+}