[JENKINS-43507] Helpers should allow indexed insertion

src/main/java/jenkins/scm/impl/form/NamedArrayList.java

@@ -94,6 +94,29 @@ public final String getName() {
    public static <E> void select(@NonNull List<? extends E> source, @NonNull String name,
                                  @CheckForNull Predicate<? super E> selector, boolean removeSelectedFromSource,
                                  @NonNull List<NamedArrayList<? extends E>> destination) {
        select(source, name, selector, removeSelectedFromSource, destination, Integer.MAX_VALUE);
    }

    /**
     * Helper method that creates a new {@link NamedArrayList} by selecting matching elements from a source list
     * and appends the new {@link NamedArrayList} to a list of {@link NamedArrayList}.
     *
     * @param source                   the list of candidate elements.
     * @param name                     the name.
     * @param selector                 the (optional) selection criteria (if {@code null} then all candidate elements
     *                                 will be added)
     * @param removeSelectedFromSource if {@code true} then the matching elements will be removed from the source.
     * @param destination              the {@link List} of {@link NamedArrayList} to add to (empty selections will
     *                                 not be added)
     * @param index                    index at which the specified selection is to be inserted (will be coerced into
     *                                 the valid range
     *                                 to remove the risk of {@link IndexOutOfBoundsException}).
     * @param <E>                      the type of element.
     */
    @SuppressWarnings("unchecked")
    public static <E> void select(@NonNull List<? extends E> source, @NonNull String name,
                                  @CheckForNull Predicate<? super E> selector, boolean removeSelectedFromSource,
                                  @NonNull List<NamedArrayList<? extends E>> destination, int index) {
        NamedArrayList<E> selection = new NamedArrayList<E>(name);
        if (selector == null) {
            selection.addAll(source);
@@ -112,7 +135,7 @@ public final String getName() {
            }
        }
        if (!selection.isEmpty()) {
            destination.add(selection);
            destination.add(Math.min(destination.size(), Math.max(index, 0)), selection);
        }
    }