Close deferred reporting before final delivery

reporter_deferred_test.go

@@ -13,7 +13,7 @@ func TestHiddenSimpleDeferredMessagesDoNotAccumulate(t *testing.T) {
 	for _, mode := range []reportingMode{modeOrdinary, modeQuiet} {
 		t.Run(fmt.Sprint(mode), func(t *testing.T) {
 			reporter := newReporter(Streams{})
-			reporter.setVisibility(mode, false, false)
+			setReporterVisibility(reporter, mode, false, false)
 			for index := 0; index < 256; index++ {
 				if err := reporter.AtEnd().Debug(fmt.Sprintf("hidden %d", index), nil); err != nil {
 					t.Fatal(err)
@@ -45,7 +45,7 @@ func TestHiddenSimpleDeferredMessagesDoNotAccumulate(t *testing.T) {
 func TestHiddenDeferredDetailsRemainDeferredAndCaptured(t *testing.T) {
 	var diagnostics bytes.Buffer
 	reporter := newReporter(Streams{Err: &diagnostics})
-	reporter.setVisibility(modeQuiet, false, false)
+	setReporterVisibility(reporter, modeQuiet, false, false)
 	failure := errors.New("hidden rendering failed")
 	var order []string
 	details := []Detail{func(w io.Writer) error {
@@ -67,3 +67,57 @@ func TestHiddenDeferredDetailsRemainDeferredAndCaptured(t *testing.T) {
 		t.Fatalf("hidden content leaked or queue retained: %q", diagnostics.String())
 	}
 }
+
+type gatedDiagnosticWriter struct {
+	bytes.Buffer
+	entered chan struct{}
+	release chan struct{}
+}
+
+func (w *gatedDiagnosticWriter) Write(p []byte) (int, error) {
+	if w.entered != nil {
+		close(w.entered)
+		w.entered = nil
+		<-w.release
+	}
+	return w.Buffer.Write(p)
+}
+
+func TestReporterDeferredAcceptanceEndsBeforeDelivery(t *testing.T) {
+	writer := &gatedDiagnosticWriter{entered: make(chan struct{}), release: make(chan struct{})}
+	entered := writer.entered
+	reporter := newReporter(Streams{Err: writer})
+	setReporterVisibility(reporter, modeVerbose, false, false)
+	deferred := reporter.AtEnd()
+	if err := deferred.Warn("accepted"); err != nil {
+		t.Fatal(err)
+	}
+	completionEntered, finishCompletion := make(chan struct{}), make(chan struct{})
+	done := make(chan Outcome, 1)
+	go func() {
+		done <- reporter.finalize(Failure("terminal"), func(r *Reporter) {
+			close(completionEntered)
+			<-finishCompletion
+			_ = r.Info("completion")
+		})
+	}()
+	<-entered
+	late := make(chan error, 1)
+	go func() { late <- deferred.Warn("late") }()
+	close(writer.release)
+	<-completionEntered
+	if err := <-late; !errors.Is(err, ErrReporterClosed) {
+		t.Errorf("late submission = %v", err)
+	}
+	if err := deferred.Debug(""); !errors.Is(err, ErrReporterClosed) {
+		t.Errorf("empty hidden submission = %v", err)
+	}
+	close(finishCompletion)
+	outcome := <-done
+	if got := writer.String(); got != "WARN: accepted\ncompletion\nERROR: terminal\n" {
+		t.Errorf("diagnostics = %q", got)
+	}
+	if outcome.Presentation.Diagnostics.State != DeliveryComplete {
+		t.Fatalf("outcome = %#v", outcome)
+	}
+}