Streamline run log and update handling

runtime/lifecycle_test.go

@@ -553,6 +553,27 @@ func TestOSProcessSupervisorRelaysRawCarriageReturn(t *testing.T) {
 	if len(output) != 1 || output[0] != "stdout:raw\r" {
 		t.Fatalf("expected raw CR to be relayed, got %+v", output)
 	}
+	if result.Stdout != "" || result.Stderr != "" {
+		t.Fatalf("relayed process output must not be duplicated into result buffers, got %+v", result)
+	}
+}
+
+func TestOSProcessSupervisorChunksLongRelayedLinesWithoutRewriting(t *testing.T) {
+	var output []string
+	result, err := (OSProcessSupervisor{}).Run(context.Background(), ProcessCommand{
+		Args: []string{"sh", "-c", "printf %70000s | tr ' ' x"},
+		OutputLine: func(stream string, line string) {
+			if stream == "stdout" {
+				output = append(output, line)
+			}
+		},
+	})
+	if err != nil || result.ExitCode != 0 {
+		t.Fatalf("run process: result=%+v err=%v", result, err)
+	}
+	if len(output) < 2 || strings.Join(output, "") != strings.Repeat("x", 70000) {
+		t.Fatalf("expected long relayed line to reassemble exactly, chunks=%d", len(output))
+	}
 }
 
 func TestProcessCommandJSONOmitsOutputCallback(t *testing.T) {