Exit with a non-zero exit code when we skip a command in the entrypoi…

…nter.

When an early step fails, our entrypointer correctly skips all subsequent steps.
Unfortunately, the containers currently exit with 0 which may be interpreted as
these steps having successfully completed.

Fixes #1439

cmd/entrypoint/main.go

@@ -53,7 +53,8 @@ func main() {
 	if err := e.Go(); err != nil {
 		switch t := err.(type) {
 		case skipError:
-			os.Exit(0)
+			log.Print("Skipping step because a previous step failed")
+			os.Exit(1)
 		case *exec.ExitError:
 			// Copied from https://stackoverflow.com/questions/10385551/get-exit-code-go
 			// This works on both Unix and Windows. Although

test/taskrun_test.go

@@ -93,8 +93,8 @@ func TestTaskRunFailure(t *testing.T) {
 	}, {
 		ContainerState: corev1.ContainerState{
 			Terminated: &corev1.ContainerStateTerminated{
-				ExitCode: 0,
-				Reason:   "Completed",
+				ExitCode: 1,
+				Reason:   "Error",
 			},
 		},
 		Name:          "world",