Gather: fix closable crash again

Add assert for nil pointer as well

README.md

@@ -50,6 +50,7 @@ Check out the **[contributing wiki](https://github.com/pion/webrtc/wiki/Contribu
 * [David Hamilton](https://github.com/dihamilton)
 * [adwpc](https://github.com/adwpc)
 * [Ori Bernstein](https://eigenstate.org)
+* [Sam Lancia](https://github.com/nerd2)
 
 ### License
 MIT License - see [LICENSE](LICENSE) for full text

gather.go

@@ -4,6 +4,7 @@ import (
 	"crypto/tls"
 	"fmt"
 	"net"
+	"reflect"
 	"sync"
 	"time"
 
@@ -22,8 +23,8 @@ type closeable interface {
 
 // Close a net.Conn and log if we have a failure
 func closeConnAndLog(c closeable, log logging.LeveledLogger, msg string) {
-	if c == nil {
-		log.Warnf("Conn is not allocated")
+	if c == nil || (reflect.ValueOf(c).Kind() == reflect.Ptr && reflect.ValueOf(c).IsNil()) {
+		log.Warnf("Conn is not allocated (%s)", msg)
 		return
 	}
 

gather_test.go

@@ -256,3 +256,15 @@ func TestTURNConcurrency(t *testing.T) {
 		runTest(ProtoTypeUDP, SchemeTypeTURNS, nil, serverListener, serverPort)
 	})
 }
+
+func TestCloseConnLog(t *testing.T) {
+	a, err := NewAgent(&AgentConfig{})
+	assert.NoError(t, err)
+
+	closeConnAndLog(nil, a.log, "normal nil")
+
+	var nc *net.UDPConn
+	closeConnAndLog(nc, a.log, "nil ptr")
+
+	assert.NoError(t, a.Close())
+}