Add discard unknown API in ruby. (#3990)

* Add discard unknown API in ruby.

* Add test for oneof message field.

* Add TestUnknown to represent unknown field data clearly.

* Only serialize the message with unknown fields itself in test.

* Move discard_unknown from Message to Google.Protobuf

2 files changed, 76 insertions, 0 deletions

diff --git a/ruby/tests/encode_decode_test.rb b/ruby/tests/encode_decode_test.rb
new file mode 100644
index 00000000..09581ab0
--- /dev/null
+++ b/ruby/tests/encode_decode_test.rb
@@ -0,0 +1,63 @@
+#!/usr/bin/ruby
+
+# generated_code.rb is in the same directory as this test.
+$LOAD_PATH.unshift(File.expand_path(File.dirname(__FILE__)))
+
+require 'generated_code_pb'
+require 'test/unit'
+
+def hex2bin(s)
+  s.scan(/../).map { |x| x.hex.chr }.join
+end
+
+class EncodeDecodeTest < Test::Unit::TestCase
+  def test_discard_unknown
+    # Test discard unknown in message.
+    unknown_msg = A::B::C::TestUnknown.new(:unknown_field => 1)
+    from = A::B::C::TestUnknown.encode(unknown_msg)
+    m = A::B::C::TestMessage.decode(from)
+    Google::Protobuf.discard_unknown(m)
+    to = A::B::C::TestMessage.encode(m)
+    assert_equal '', to
+
+    # Test discard unknown for singular message field.
+    unknown_msg = A::B::C::TestUnknown.new(
+	    :optional_unknown =>
+	    A::B::C::TestUnknown.new(:unknown_field => 1))
+    from = A::B::C::TestUnknown.encode(unknown_msg)
+    m = A::B::C::TestMessage.decode(from)
+    Google::Protobuf.discard_unknown(m)
+    to = A::B::C::TestMessage.encode(m.optional_msg)
+    assert_equal '', to
+
+    # Test discard unknown for repeated message field.
+    unknown_msg = A::B::C::TestUnknown.new(
+	    :repeated_unknown =>
+	    [A::B::C::TestUnknown.new(:unknown_field => 1)])
+    from = A::B::C::TestUnknown.encode(unknown_msg)
+    m = A::B::C::TestMessage.decode(from)
+    Google::Protobuf.discard_unknown(m)
+    to = A::B::C::TestMessage.encode(m.repeated_msg[0])
+    assert_equal '', to
+
+    # Test discard unknown for map value message field.
+    unknown_msg = A::B::C::TestUnknown.new(
+	    :map_unknown =>
+	    {"" => A::B::C::TestUnknown.new(:unknown_field => 1)})
+    from = A::B::C::TestUnknown.encode(unknown_msg)
+    m = A::B::C::TestMessage.decode(from)
+    Google::Protobuf.discard_unknown(m)
+    to = A::B::C::TestMessage.encode(m.map_string_msg[''])
+    assert_equal '', to
+
+    # Test discard unknown for oneof message field.
+    unknown_msg = A::B::C::TestUnknown.new(
+	    :oneof_unknown =>
+	    A::B::C::TestUnknown.new(:unknown_field => 1))
+    from = A::B::C::TestUnknown.encode(unknown_msg)
+    m = A::B::C::TestMessage.decode(from)
+    Google::Protobuf.discard_unknown(m)
+    to = A::B::C::TestMessage.encode(m.oneof_msg)
+    assert_equal '', to
+  end
+end
diff --git a/ruby/tests/generated_code.proto b/ruby/tests/generated_code.proto
index 62fd83ed..3b934bd6 100644
--- a/ruby/tests/generated_code.proto
+++ b/ruby/tests/generated_code.proto
@@ -57,6 +57,9 @@ message TestMessage {
   }
 
   NestedMessage nested_message = 80;
+
+  // Reserved for non-existing field test.
+  // int32 non_exist = 89;
 }
 
 enum TestEnum {
@@ -65,3 +68,13 @@ enum TestEnum {
   B = 2;
   C = 3;
 }
+
+message TestUnknown {
+  TestUnknown optional_unknown = 11;
+  repeated TestUnknown repeated_unknown = 31;
+  oneof my_oneof {
+    TestUnknown oneof_unknown = 51;
+  }
+  map<string, TestUnknown> map_unknown = 67;
+  int32 unknown_field = 89;
+}