/**
     * Key to get the TransformerContext from the SessionData
     */
    Object KEY = ModelTransformerContext.class;

    /**
     * Get the value of the Maven user property.
     */
    String getUserProperty(String key);

    /**
     * Get the model based on the path when resolving the parent based on relativePath.
     *
     * @param from    the requiring model
     * @param pomFile the path to the pomFile

        assertThat(emptyProject.getAttachedArtifacts()).isEmpty();
    }

    private static class NoTransformerContext implements TransformerContext {
        @Override
        public String getUserProperty(String key) {
            return null;
        }

        @Override
        public Model getRawModel(Path from, String groupId, String artifactId) throws IllegalStateException {

            return model;
        }
    }

    DefaultModelTransformerContext(ModelProcessor modelLocator) {
        this.modelLocator = modelLocator;
    }

    @Override
    public String getUserProperty(String key) {
        return userProperties.get(key);
    }

    @Override
    public Model getRawModel(Path from, Path p) {
        return Holder.deref(modelByPath.get(p));
    }

    @Override

        if (version != null) {
            for (String key : Arrays.asList("changelist", "revision", "sha1")) {
                String val = context.getUserProperty(key);
                if (val != null) {
                    version = version.replace("${" + key + "}", val);
                }
            }
        }
        return version;
    }

            @Override
            public Path locate(Path path) {
                return context.locate(path);
            }

            @Override
            public String getUserProperty(String key) {
                return context.userProperties.computeIfAbsent(
                        key, k -> request.getUserProperties().get(key));
            }

            @Override