Check if symlinks are the same during filesystem diffing

Author: Priya Wadhwa

pkg/util/fs_utils.go

@@ -130,6 +130,18 @@ func CreateDirectoryEntries(root string, entryNames []string) (entries []Directo
 	return entries
 }
 
+func CheckSameSymlink(f1name, f2name string) (bool, error) {
+	link1, err := os.Readlink(f1name)
+	if err != nil {
+		return false, err
+	}
+	link2, err := os.Readlink(f2name)
+	if err != nil {
+		return false, err
+	}
+	return (link1 == link2), nil
+}
+
 func CheckSameFile(f1name, f2name string) (bool, error) {
 	// Check first if files differ in size and immediately return
 	f1stat, err := os.Stat(f1name)

util/diff_utils.go

@@ -194,17 +194,30 @@ func GetModifiedEntries(d1, d2 pkgutil.Directory) []string {
 		f1path := fmt.Sprintf("%s%s", d1.Root, f)
 		f2path := fmt.Sprintf("%s%s", d2.Root, f)
 
-		f1stat, err := os.Stat(f1path)
+		f1stat, err := os.Lstat(f1path)
 		if err != nil {
 			logrus.Errorf("Error checking directory entry %s: %s\n", f, err)
 			continue
 		}
-		f2stat, err := os.Stat(f2path)
+		f2stat, err := os.Lstat(f2path)
 		if err != nil {
 			logrus.Errorf("Error checking directory entry %s: %s\n", f, err)
 			continue
 		}
 
+		// If the directory entry is a symlink, make sure the symlinks point to the same place
+		if f1stat.Mode()&os.ModeSymlink != 0 && f2stat.Mode()&os.ModeSymlink != 0 {
+			same, err := pkgutil.CheckSameSymlink(f1path, f2path)
+			if err != nil {
+				logrus.Errorf("Error determining if symlink %s and %s are equivalent: %s\n", f1path, f2path, err)
+				continue
+			}
+			if !same {
+				modified = append(modified, f)
+			}
+			continue
+		}
+
 		// If the directory entry in question is a tar, verify that the two have the same size
 		if pkgutil.IsTar(f1path) {
 			if f1stat.Size() != f2stat.Size() {