}
        List<Object> newItems = value.replace(original, supplier);
        if (newItems == null) {
            return this;
        }
        DefaultConfigurableFileCollection newFiles = new DefaultConfigurableFileCollection(null, resolver, dependencyFactory, patternSetFactory, host);
        newFiles.from(newItems);
        return newFiles;
    }

    private void assertMutable() {

package org.gradle.internal.serialize.codecs.core

import org.gradle.api.file.ConfigurableFileCollection
import org.gradle.api.internal.file.FileCollectionFactory
import org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection
import org.gradle.internal.serialize.graph.Codec
import org.gradle.internal.serialize.graph.ReadContext
import org.gradle.internal.serialize.graph.WriteContext

 * limitations under the License.
 */

package org.gradle.api.internal.file;

import com.google.common.collect.ImmutableSet;
import org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection;
import org.gradle.api.internal.file.collections.FileCollectionAdapter;
import org.gradle.api.internal.file.collections.ListBackedFileSet;
import org.gradle.api.internal.provider.PropertyHost;

    @Override
    public ConfigurableFileCollection configurableFiles() {
        return new DefaultConfigurableFileCollection(null, fileResolver, taskDependencyFactory, patternSetFactory, propertyHost);
    }

    @Override
    public ConfigurableFileCollection configurableFiles(String displayName) {
        return new DefaultConfigurableFileCollection(displayName, fileResolver, taskDependencyFactory, patternSetFactory, propertyHost);
    }

    def collection = new DefaultConfigurableFileCollection("<display>", fileResolver, taskDependencyFactory, patternSetFactory, host)

    @Override
    AbstractFileCollection containing(File... files) {
        def resolver = Stub(FileResolver)
        _ * resolver.resolve(_) >> { File f -> f }