Explicitly disallow prefix recursion on objects with wildcards

This fixes an infinite loop that can occur if a user runs
ls gs://bucket/object* on a bucket that contains an object named
"gs://bucket/object*/"

gslib/tests/test_ls.py

@@ -450,6 +450,30 @@ def test_recursive_list_trailing_two_slash(self):
     # removed.
     self.assertIn(suri(bucket_uri) + '//', stdout)
 
+  def test_wildcard_prefix(self):
+    """Tests that an object name with a wildcard does not infinite loop."""
+    bucket_uri = self.CreateBucket()
+    wildcard_folder_object = 'wildcard*/'
+    object_matching_folder = 'wildcard10/foo'
+    self.CreateObject(bucket_uri=bucket_uri, object_name=wildcard_folder_object,
+                      contents='foo')
+    self.CreateObject(bucket_uri=bucket_uri, object_name=object_matching_folder,
+                      contents='foo')
+    self.AssertNObjectsInBucket(bucket_uri, 2)
+    stderr = self.RunGsUtil(['ls', suri(bucket_uri, 'wildcard*')],
+                            return_stderr=True, expected_status=1)
+    self.assertIn('Cloud folder %s%s contains a wildcard' %
+                  (suri(bucket_uri), '/wildcard*/'), stderr)
+
+    # Listing with a flat wildcard should still succeed.
+    # Use @Retry as hedge against bucket listing eventual consistency.
+    @Retry(AssertionError, tries=3, timeout_secs=1)
+    def _Check():
+      stdout = self.RunGsUtil(['ls', '-l', suri(bucket_uri, '**')],
+                              return_stdout=True)
+      self.assertNumLines(stdout, 3)  # 2 object lines, one summary line.
+    _Check()
+
   @SkipForS3('S3 anonymous access is not supported.')
   def test_get_object_without_list_bucket_permission(self):
     # Bucket is not publicly readable by default.

gslib/wildcard_iterator.py

@@ -220,6 +220,17 @@ def __iter__(self, bucket_listing_fields=None,
                             self.all_versions or single_version_request))
             else:  # CloudApi.CsObjectOrPrefixType.PREFIX
               prefix = obj_or_prefix.data
+
+              if ContainsWildcard(prefix):
+                # TODO: Disambiguate user-supplied strings from iterated
+                # prefix and object names so that we can better reason
+                # about wildcards and handle this case without raising an error.
+                raise CommandException(
+                    'Cloud folder %s%s contains a wildcard; gsutil does '
+                    'not currently support objects with wildcards in their '
+                    'name.'
+                    % (bucket_url_string, prefix))
+
               # If the prefix ends with a slash, remove it.  Note that we only
               # remove one slash so that we can successfully enumerate dirs
               # containing multiple slashes.