Fix a bug where charlock_holmes was used needlessly to encode strings

lib/gitlab/encoding_helper.rb

@@ -14,14 +14,7 @@ module Gitlab
     ENCODING_CONFIDENCE_THRESHOLD = 50
 
     def encode!(message)
-      return nil unless message.respond_to?(:force_encoding)
-      return message if message.encoding == Encoding::UTF_8 && message.valid_encoding?
-
-      if message.respond_to?(:frozen?) && message.frozen?
-        message = message.dup
-      end
-
-      message.force_encoding("UTF-8")
+      message = force_encode_utf8(message)
       return message if message.valid_encoding?
 
       # return message if message type is binary
@@ -35,6 +28,8 @@ module Gitlab
 
       # encode and clean the bad chars
       message.replace clean(message)
+    rescue ArgumentError
+      return nil
     rescue
       encoding = detect ? detect[:encoding] : "unknown"
       "--broken encoding: #{encoding}"
@@ -54,8 +49,8 @@ module Gitlab
     end
 
     def encode_utf8(message)
-      return nil unless message.is_a?(String)
-      return message if message.encoding == Encoding::UTF_8 && message.valid_encoding?
+      message = force_encode_utf8(message)
+      return message if message.valid_encoding?
 
       detect = CharlockHolmes::EncodingDetector.detect(message)
       if detect && detect[:encoding]
@@ -69,6 +64,8 @@ module Gitlab
       else
         clean(message)
       end
+    rescue ArgumentError
+      return nil
     end
 
     def encode_binary(s)
@@ -83,6 +80,15 @@ module Gitlab
 
     private
 
+    def force_encode_utf8(message)
+      raise ArgumentError unless message.respond_to?(:force_encoding)
+      return message if message.encoding == Encoding::UTF_8 && message.valid_encoding?
+
+      message = message.dup if message.respond_to?(:frozen?) && message.frozen?
+
+      message.force_encoding("UTF-8")
+    end
+
     def clean(message)
       message.encode("UTF-16BE", undef: :replace, invalid: :replace, replace: "")
         .encode("UTF-8")

lib/gitlab/git.rb

@@ -11,7 +11,7 @@ module Gitlab
       include Gitlab::EncodingHelper
 
       def ref_name(ref)
-        encode_utf8(ref).sub(/\Arefs\/(tags|heads|remotes)\//, '')
+        encode!(ref).sub(/\Arefs\/(tags|heads|remotes)\//, '')
       end
 
       def branch_name(ref)

spec/lib/gitlab/encoding_helper_spec.rb

@@ -120,6 +120,24 @@ describe Gitlab::EncodingHelper do
     it 'returns empty string on conversion errors' do
       expect { ext_class.encode_utf8('') }.not_to raise_error(ArgumentError)
     end
+
+    context 'with strings that can be forcefully encoded into utf8' do
+      let(:test_string) do
+        "refs/heads/FixSymbolsTitleDropdown".encode("ASCII-8BIT")
+      end
+      let(:expected_string) do
+        "refs/heads/FixSymbolsTitleDropdown".encode("UTF-8")
+      end
+
+      subject { ext_class.encode_utf8(test_string) }
+
+      it "doesn't use CharlockHolmes if the encoding can be forced into utf_8" do
+        expect(CharlockHolmes::EncodingDetector).not_to receive(:detect)
+
+        expect(subject).to eq(expected_string)
+        expect(subject.encoding.name).to eq('UTF-8')
+      end
+    end
   end
 
   describe '#clean' do