Follow symlinks to directories when scanning

scanner/change_detector.go

@@ -61,7 +61,12 @@ func (s *ChangeDetector) loadDir(dirPath string) (children []string, lastUpdated
 		return
 	}
 	for _, f := range files {
-		if f.IsDir() {
+		isDir, err := IsDirOrSymlinkToDir(dirPath, f)
+		// Skip invalid symlinks
+		if err != nil {
+			continue
+		}
+		if isDir {
 			children = append(children, filepath.Join(dirPath, f.Name()))
 		} else {
 			if f.ModTime().After(lastUpdated) {
@@ -72,6 +77,26 @@ func (s *ChangeDetector) loadDir(dirPath string) (children []string, lastUpdated
 	return
 }
 
+// IsDirOrSymlinkToDir returns true if and only if the Dirent represents a file
+// system directory, or a symbolic link to a directory. Note that if the Dirent
+// is not a directory but is a symbolic link, this method will resolve by
+// sending a request to the operating system to follow the symbolic link.
+// Copied from github.com/karrick/godirwalk
+func IsDirOrSymlinkToDir(baseDir string, info os.FileInfo) (bool, error) {
+	if info.IsDir() {
+		return true, nil
+	}
+	if info.Mode()&os.ModeSymlink == 0 {
+		return false, nil
+	}
+	// Does this symlink point to a directory?
+	info, err := os.Stat(filepath.Join(baseDir, info.Name()))
+	if err != nil {
+		return false, err
+	}
+	return info.IsDir(), nil
+}
+
 func (s *ChangeDetector) loadMap(dirMap dirInfoMap, path string, since time.Time, maybe bool) error {
 	children, lastUpdated, err := s.loadDir(path)
 	if err != nil {

scanner/change_detector_test.go

@@ -110,6 +110,25 @@ var _ = Describe("ChangeDetector", func() {
 		Expect(deleted).To(BeEmpty())
 		Expect(changed).To(ConsistOf(P("a/b")))
 	})
+
+	Describe("IsDirOrSymlinkToDir", func() {
+		It("returns true for normal dirs", func() {
+			dir, _ := os.Stat("tests/fixtures")
+			Expect(IsDirOrSymlinkToDir("tests", dir)).To(BeTrue())
+		})
+		It("returns true for symlinks to dirs", func() {
+			dir, _ := os.Stat("tests/fixtures/symlink2dir")
+			Expect(IsDirOrSymlinkToDir("tests/fixtures", dir)).To(BeTrue())
+		})
+		It("returns false for files", func() {
+			dir, _ := os.Stat("tests/fixtures/test.mp3")
+			Expect(IsDirOrSymlinkToDir("tests/fixtures", dir)).To(BeFalse())
+		})
+		It("returns false for symlinks to files", func() {
+			dir, _ := os.Stat("tests/fixtures/symlink")
+			Expect(IsDirOrSymlinkToDir("tests/fixtures", dir)).To(BeFalse())
+		})
+	})
 })
 
 // I hate time-based tests....

tests/fixtures/symlink

@@ -0,0 +1 @@
+index.html

tests/fixtures/symlink2dir

@@ -0,0 +1 @@
+../

tests/fixtures/synlink_invalid

@@ -0,0 +1 @@
+INVALID