don't follow links

Author: 2ZeroSix

lib/src/package.dart

@@ -245,7 +245,7 @@ class Package {
     return Ignore.listFiles(
       beneath: beneath,
       listDir: (dir) {
-        var contents = Directory(resolve(dir)).listSync(recursive: true);
+        var contents = Directory(resolve(dir)).listSync(followLinks: false);
         if (!recursive) {
           contents = contents.where((entity) => entity is! Directory).toList();
         }

lib/src/validator/gitignore.dart

@@ -45,7 +45,7 @@ class GitignoreValidator extends Validator {
       final unignoredByGitignore = Ignore.listFiles(
         beneath: beneath,
         listDir: (dir) {
-          var contents = Directory(resolve(dir)).listSync();
+          var contents = Directory(resolve(dir)).listSync(followLinks: false);
           return contents.map((entity) =>
               p.posix.joinAll(p.split(p.relative(entity.path, from: root))));
         },

test/package_list_files_test.dart

@@ -118,7 +118,8 @@ void main() {
           (e) => e.message,
           'message',
           contains(
-              'Pub does not support publishing packages with non-resolving symlink:'),
+            'Pub does not support publishing packages with directory symlinks',
+          ),
         ),
       ),
     );