This is possibly a bug with DA/DU.

public enum Action { IGNORE, REJECT }
private static void bad() {
    String s;
    switch (getAction()) {
        case IGNORE:
            s = "foo";
            break;
        case REJECT:
            throw new RuntimeException("REJECTED");
    };
    System.out.println(s); // <------- variable s might not have been initialized
}

private static void ok() {
    String s = switch (getAction()) {
        case IGNORE:
            yield "foo";
        case REJECT:
            throw new RuntimeException("REJECTED");
    };
    System.out.println(s); // ok !
}

reported and discussed in: https://mail.openjdk.org/pipermail/amber-dev/2024-December/009139.html