Merge pull request #259 from onsi/issue-258

Avoid sending a signal or killing the session if the process is not alive

gexec/session.go

@@ -151,11 +151,7 @@ If the command has already exited, Kill returns silently.
 The session is returned to enable chaining.
 */
 func (s *Session) Kill() *Session {
-	if s.ExitCode() != -1 {
-		return s
-	}
-	s.Command.Process.Kill()
-	return s
+	return s.Signal(syscall.SIGKILL)
 }
 
 /*
@@ -188,10 +184,9 @@ If the command has already exited, Signal returns silently.
 The session is returned to enable chaining.
 */
 func (s *Session) Signal(signal os.Signal) *Session {
-	if s.ExitCode() != -1 {
-		return s
+	if s.processIsAlive() {
+		s.Command.Process.Signal(signal)
 	}
-	s.Command.Process.Signal(signal)
 	return s
 }
 
@@ -215,6 +210,10 @@ func (s *Session) monitorForExit(exited chan<- struct{}) {
 	close(exited)
 }
 
+func (s *Session) processIsAlive() bool {
+	return s.ExitCode() == -1 && s.Command.Process != nil
+}
+
 var trackedSessions = []*Session{}
 var trackedSessionsMutex = &sync.Mutex{}
 

gexec/session_test.go

@@ -127,6 +127,13 @@ var _ = Describe("Session", func() {
 			Ω(session).ShouldNot(Exit(), "Should not exit immediately...")
 			Eventually(session).Should(Exit(128 + 6))
 		})
+
+		It("should ignore sending a signal if the command did not start", func() {
+			session, err := Start(exec.Command("notexisting"), GinkgoWriter, GinkgoWriter)
+			Expect(err).To(HaveOccurred())
+
+			Expect(func() { session.Signal(syscall.SIGUSR1) }).NotTo(Panic())
+		})
 	})
 
 	Context("tracking sessions", func() {