}
                }
            }

            @Override
            public void visitFileTree(File root, PatternSet patterns, FileTreeInternal fileTree) {
                visitor.visitFileTree(root, patterns, fileTree);
            }

            @Override

            @Override
            public void visitFileTree(File root, PatternSet patterns, FileTreeInternal fileTree) {
                PatternSet intersect = patterns.intersect();
                intersect.copyFrom(FilteredMinimalFileTree.this.patterns);
                visitor.visitFileTree(root, intersect, owner);
            }

            @Override

            nestedVisitor.visitFileTree(dir, sourcePatterns, o)
        }
        1 * sourcePatterns.intersect() >> intersectPatterns
        1 * intersectPatterns.copyFrom(patterns)
        1 * visitor.visitFileTree(dir, intersectPatterns, owner)
        0 * _
    }

    def "applies filters to mirror"() {

        tree.visitStructure(new MinimalFileTree.MinimalFileTreeStructureVisitor() {

            @Override
            public void visitFileTree(File root, PatternSet patterns, FileTreeInternal fileTree) {
                visitor.visitFileTree(root, patterns, fileTree);
            }

            @Override

    interface MinimalFileTreeStructureVisitor {

        /**
         * Visits a file tree at a root file on the file system (potentially filtered).
         */
        void visitFileTree(File root, PatternSet patterns, FileTreeInternal fileTree);

        /**
         * Visits a file tree whose content is generated from the contents of a file.
         */

        trees[1].dir == dir2

        1 * source1.visitStructure(_) >> { FileCollectionStructureVisitor visitor ->
            visitor.visitFileTree(dir1, Stub(PatternSet), source1)
        }
        1 * source2.visitStructure(_) >> { FileCollectionStructureVisitor visitor ->
            visitor.visitFileTree(dir2, Stub(PatternSet), source2)
        }
        0 * _
    }

                                collections.add(content);
                            }
                        }

                        @Override
                        public void visitFileTree(File root, PatternSet patterns, FileTreeInternal fileTree) {
                            collections.add(fileTree);
                        }

                        @Override

            for (File file : contents) {
                roots.add(fileSystemAccess.read(file.getAbsolutePath()));
            }
        }

        @Override
        public void visitFileTree(File root, PatternSet patterns, FileTreeInternal fileTree) {
            fileSystemAccess.read(
                root.getAbsolutePath(),
                new PatternSetSnapshottingFilter(patterns, stat)
            )

        when:
        fileTree.visitStructure(visitor, owner)

        then:
        1 * visitor.visitFileTree(generatedFile, _, owner) >> { d, p, t ->
            assert p.isEmpty()
            assert generatedFile.isFile()
            assert generatedFile.text == "contents!"
        }

                            contents.forEach(location -> taskInputs.add(location.getAbsolutePath()));
                        }

                        @Override
                        public void visitFileTree(File root, PatternSet patterns, FileTreeInternal fileTree) {
                            if (patterns.isEmpty()) {
                                taskInputs.add(root.getAbsolutePath());
                            } else {