Enforce type safety in `NodeCrashEvent` #602 (#607)

geth/node/manager.go

@@ -93,7 +93,7 @@ func (m *NodeManager) startNode(config *params.NodeConfig) (<-chan struct{}, err
 			signal.Send(signal.Envelope{
 				Type: signal.EventNodeCrashed,
 				Event: signal.NodeCrashEvent{
-					Error: fmt.Errorf("%v: %v", ErrNodeStartFailure, startErr).Error(),
+					Error: fmt.Errorf("%v: %v", ErrNodeStartFailure, startErr),
 				},
 			})
 			return
@@ -117,7 +117,7 @@ func (m *NodeManager) startNode(config *params.NodeConfig) (<-chan struct{}, err
 			signal.Send(signal.Envelope{
 				Type: signal.EventNodeCrashed,
 				Event: signal.NodeCrashEvent{
-					Error: ErrRPCClient.Error(),
+					Error: ErrRPCClient,
 				},
 			})
 			return

geth/node/utils.go

@@ -10,13 +10,13 @@ import (
 // HaltOnPanic recovers from panic, logs issue, sends upward notification, and exits
 func HaltOnPanic() {
 	if r := recover(); r != nil {
-		strErr := fmt.Sprintf("%v: %v", ErrNodeRunFailure, r)
+		err := fmt.Errorf("%v: %v", ErrNodeRunFailure, r)
 
 		// send signal up to native app
 		signal.Send(signal.Envelope{
 			Type: signal.EventNodeCrashed,
 			Event: signal.NodeCrashEvent{
-				Error: strErr,
+				Error: err,
 			},
 		})
 

geth/signal/signals.go

@@ -9,8 +9,9 @@ import "C"
 import (
 	"encoding/json"
 
-	"github.com/status-im/status-go/geth/log"
 	"sync"
+
+	"github.com/status-im/status-go/geth/log"
 )
 
 const (
@@ -39,7 +40,16 @@ type Envelope struct {
 
 // NodeCrashEvent is special kind of error, used to report node crashes
 type NodeCrashEvent struct {
-	Error string `json:"error"`
+	Error error `json:"error"`
+}
+
+// MarshalJSON implements the json.Marshaller interface.
+func (e NodeCrashEvent) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		Error string `json:"error"`
+	}{
+		Error: e.Error.Error(),
+	})
 }
 
 // NodeNotificationHandler defines a handler able to process incoming node events.

geth/signal/signals_test.go

@@ -0,0 +1,21 @@
+package signal
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestNodeCrashEventJSONMarshalling(t *testing.T) {
+	errorMsg := "TestNodeCrashEventJSONMarshallingError"
+	expectedJSON := fmt.Sprintf(`{"error":"%s"}`, errorMsg)
+	nodeCrashEvent := &NodeCrashEvent{
+		Error: errors.New(errorMsg),
+	}
+	marshalled, err := json.Marshal(nodeCrashEvent)
+	require.NoError(t, err)
+	require.Equal(t, expectedJSON, string(marshalled))
+}

geth/transactions/queue/utils.go

@@ -20,7 +20,7 @@ func HaltOnPanic() {
 		signal.Send(signal.Envelope{
 			Type: signal.EventNodeCrashed,
 			Event: signal.NodeCrashEvent{
-				Error: err.Error(),
+				Error: err,
 			},
 		})