if (configuration == null) {
                configuration = XmlNode.newInstance("configuration");
            }
            UnaryOperator<String> cb = Interpolator.memoize(callback);
            UnaryOperator<String> it = s -> interpolator.interpolate(s, cb);
            configuration = new ExtensionInterpolator(it).transform(configuration);

            binder.bind(XmlNode.class)

        assertViolations(result, 0, 0, 2);

        assertEquals(
                "'profiles.profile[exists-project-version].activation.file.exists' "
                        + "Failed to interpolate profile activation property ${project.version}/test.txt: "
                        + "${project.version} expressions are not supported during profile activation.",
                result.getWarnings().get(0));

    }

    public interface ContentTransformer {
        /**
         * Interpolate the value read from the xpp3 document
         * @param source The source value
         * @param fieldName A description of the field being interpolated. The implementation may use this to
         *                           log stuff.
         * @return The interpolated value.
         */
        String transform(String source, String fieldName);

     */
    public interface ContentTransformer {
        /**
         * Interpolate the value read from the xpp3 document
         *
         * @param source    The source value
         * @param fieldName A description of the field being interpolated. The implementation may use this to
         *                  log stuff.
         * @return The interpolated value.
         */
        String transform(String source, String fieldName);

        // Test that interpolation works (even though there's nothing to interpolate here)
        UpgradeOptions interpolated = (CommonsCliUpgradeOptions) options.interpolate(s -> s);

        assertTrue(interpolated.plugins().isPresent(), "Interpolated options should preserve --plugins");
        assertTrue(interpolated.plugins().get(), "Interpolated --plugins should be true");
    }

    @Test

      // index * (dataset.length - 1) / scale. If there is no remainder, we can just find the value
      // whose index in the sorted dataset equals the quotient; if there is a remainder, we
      // interpolate between that and the next value.

      // Since index and (dataset.length - 1) are non-negative ints, their product can be expressed
      // as a long, without risk of overflow:

    }

    public interface ContentTransformer {
        /**
         * Interpolate the value read from the xpp3 document
         *
         * @param source The source value
         * @param fieldName A description of the field being interpolated. The implementation may use this to
         *         log stuff.
         * @return The interpolated value.
         */
        String transform(String source, String fieldName);

    public interface ContentTransformer {
        /**
         * Interpolate the value read from the xpp3 document
         * @param source The source value
         * @param fieldName A description of the field being interpolated. The implementation may use this to
         *                           log stuff.
         * @return The interpolated value.
         */
        String transform(String source, String fieldName);

            parserRequest.logger().error("Error populating user properties", e);
        }

        // options: interpolate
        if (context.options != null) {
            context.options = context.options.interpolate(Interpolator.chain(
                    context.extraInterpolationSource()::get,
                    context.userProperties::get,

    interface Transformer {
        /**
         * Interpolate the value read from the xml document
         *
         * @param source    The source value
         * @param fieldName A description of the field being interpolated. The implementation may use this to
         *                  log stuff.
         * @return the interpolated value
         */
        String transform(String source, String fieldName);
    }