feat(process): include exit errors in action payloads

actions.go

@@ -194,7 +194,7 @@ type ActionProcessExited struct {
 	ID       string
 	ExitCode int
 	Duration time.Duration
-	Error    error // Reserved for future exit metadata; currently left unset by the service
+	Error    error // Set for failed starts, non-zero exits, or killed processes.
 }
 
 // ActionProcessKilled is broadcast when a process is terminated.

service.go

@@ -215,6 +215,7 @@ func (s *Service) StartWithOptions(ctx context.Context, opts RunOptions) (*Proce
 
 	// Start the process
 	if err := cmd.Start(); err != nil {
+		startErr := coreerr.E("Service.StartWithOptions", "failed to start process", err)
 		proc.mu.Lock()
 		proc.Status = StatusFailed
 		proc.ExitCode = -1
@@ -232,10 +233,10 @@ func (s *Service) StartWithOptions(ctx context.Context, opts RunOptions) (*Proce
 				ID:       id,
 				ExitCode: -1,
 				Duration: proc.Duration,
-				Error:    nil,
+				Error:    startErr,
 			})
 		}
-		return proc, coreerr.E("Service.StartWithOptions", "failed to start process", err)
+		return proc, startErr
 	}
 
 	proc.mu.Lock()
@@ -291,7 +292,7 @@ func (s *Service) StartWithOptions(ctx context.Context, opts RunOptions) (*Proce
 		err := cmd.Wait()
 
 		duration := time.Since(proc.StartedAt)
-		status, exitCode, _, signalName := classifyProcessExit(err)
+		status, exitCode, exitErr, signalName := classifyProcessExit(err)
 
 		proc.mu.Lock()
 		proc.Duration = duration
@@ -309,7 +310,7 @@ func (s *Service) StartWithOptions(ctx context.Context, opts RunOptions) (*Proce
 			ID:       id,
 			ExitCode: exitCode,
 			Duration: duration,
-			Error:    nil,
+			Error:    exitErr,
 		}
 
 		if c := s.coreApp(); c != nil {

service_test.go

@@ -337,7 +337,8 @@ func TestService_Actions(t *testing.T) {
 		defer mu.Unlock()
 		assert.Len(t, exited, 1)
 		assert.Equal(t, proc.ID, exited[0].ID)
-		assert.Nil(t, exited[0].Error)
+		require.Error(t, exited[0].Error)
+		assert.Contains(t, exited[0].Error.Error(), "process was killed")
 		assert.Equal(t, StatusKilled, proc.Status)
 	})
 
@@ -370,7 +371,42 @@ func TestService_Actions(t *testing.T) {
 		defer mu.Unlock()
 		require.Len(t, exited, 1)
 		assert.Equal(t, -1, exited[0].ExitCode)
-		assert.Nil(t, exited[0].Error)
+		require.Error(t, exited[0].Error)
+		assert.Contains(t, exited[0].Error.Error(), "failed to start process")
+	})
+
+	t.Run("broadcasts exited error on non-zero exit", func(t *testing.T) {
+		c := framework.New()
+
+		factory := NewService(Options{})
+		raw, err := factory(c)
+		require.NoError(t, err)
+		svc := raw.(*Service)
+
+		var exited []ActionProcessExited
+		var mu sync.Mutex
+
+		c.RegisterAction(func(cc *framework.Core, msg framework.Message) framework.Result {
+			mu.Lock()
+			defer mu.Unlock()
+			if m, ok := msg.(ActionProcessExited); ok {
+				exited = append(exited, m)
+			}
+			return framework.Result{OK: true}
+		})
+
+		proc, err := svc.Start(context.Background(), "sh", "-c", "exit 7")
+		require.NoError(t, err)
+
+		<-proc.Done()
+		time.Sleep(10 * time.Millisecond)
+
+		mu.Lock()
+		defer mu.Unlock()
+		require.Len(t, exited, 1)
+		assert.Equal(t, 7, exited[0].ExitCode)
+		require.Error(t, exited[0].Error)
+		assert.Contains(t, exited[0].Error.Error(), "process exited with code 7")
 	})
 }