Fix progress callback error reporting

bindings/fileTransfer.go

@@ -203,6 +203,7 @@ func (f *FileTransfer) Send(payload, recipientID []byte, retry float32,
 		base64.StdEncoding.EncodeToString(recipientID))
 
 	// Unmarshal recipient ID
+	jww.INFO.Printf("** FileTransfer.Send before id.Unmarshal")
 	recipient, err := id.Unmarshal(recipientID)
 	if err != nil {
 		return nil, err
@@ -219,7 +220,11 @@ func (f *FileTransfer) Send(payload, recipientID []byte, retry float32,
 			Transmitted: int(arrived),
 			Total:       int(total),
 		}
-		pm, err := json.Marshal(progress)
+		pm, err2 := json.Marshal(progress)
+		if err2 != nil {
+			jww.FATAL.Panicf(
+				"[FT] Failed to JSON marshal sent Progress object: %+v", err)
+		}
 		callback.Callback(pm, &FilePartTracker{t}, err)
 	}
 
@@ -295,7 +300,11 @@ func (f *FileTransfer) RegisterSentProgressCallback(tidBytes []byte,
 			Transmitted: int(arrived),
 			Total:       int(total),
 		}
-		pm, err := json.Marshal(progress)
+		pm, err2 := json.Marshal(progress)
+		if err2 != nil {
+			jww.FATAL.Panicf(
+				"[FT] Failed to JSON marshal sent Progress object: %+v", err)
+		}
 		callback.Callback(pm, &FilePartTracker{t}, err)
 	}
 	p := time.Millisecond * time.Duration(period)
@@ -325,7 +334,11 @@ func (f *FileTransfer) RegisterReceivedProgressCallback(tidBytes []byte,
 			Transmitted: int(received),
 			Total:       int(total),
 		}
-		pm, err := json.Marshal(progress)
+		pm, err2 := json.Marshal(progress)
+		if err2 != nil {
+			jww.FATAL.Panicf(
+				"[FT] Failed to JSON marshal received Progress object: %+v", err)
+		}
 		callback.Callback(pm, &FilePartTracker{t}, err)
 	}
 	p := time.Millisecond * time.Duration(period)

bindings/fileTransfer_test.go

@@ -17,7 +17,9 @@ import (
 	"gitlab.com/xx_network/primitives/id"
 )
 
+// Creates example JSON outputs used in documentation.
 func TestFileTransfer_inputs(t *testing.T) {
+	// FileSend
 	fs := &FileSend{
 		Name:     "testfile.txt",
 		Type:     "text file",
@@ -28,6 +30,7 @@ func TestFileTransfer_inputs(t *testing.T) {
 	t.Log("FileSend example JSON:")
 	fmt.Printf("%s\n\n", fsm)
 
+	// ReceivedFile
 	tid, _ := fileTransfer.NewTransferID(csprng.NewSystemRNG())
 	sid, _ := id.NewRandomID(csprng.NewSystemRNG(), id.User)
 	rf := &ReceivedFile{
@@ -42,6 +45,7 @@ func TestFileTransfer_inputs(t *testing.T) {
 	t.Log("ReceivedFile example JSON:")
 	fmt.Printf("%s\n\n", rfm)
 
+	// Progress
 	p := &Progress{
 		TransferID:  &tid,
 		Completed:   false,
@@ -52,6 +56,7 @@ func TestFileTransfer_inputs(t *testing.T) {
 	t.Log("Progress example JSON:")
 	fmt.Printf("%s\n\n", pm)
 
+	// EventReport
 	er := &EventReport{
 		Priority:  1,
 		Category:  "Test Events",