title: go protobuf: Cannot find package "." in github.com/gogo/protobuf/proto and m.TimeStamp.MarshalToSizedBuffer undefined
body: <p>Question as per title.
  Tried to compile in 2 ways gogoproto and golangprotobuf.</p>
  
  <p>Wrote tests for both, and both won't marshal.</p>
  
  <p>msg.proto</p>
  
  <pre><code>syntax = "proto3";
  
  import "google/protobuf/timestamp.proto";
  
  package msg;
  
  message Message {
      string Name = 1;
      google.protobuf.Timestamp TimeStamp = 2;
  }
  
  </code></pre>
  
  <p>demo_test.go</p>
  
  <pre><code>package msg
  
  import (
      "testing"
      "time"
  
      // gogo "github.com/gogo/protobuf/proto"
      "github.com/golang/protobuf/proto"
      "github.com/golang/protobuf/ptypes/timestamp"
  )
  
  var msg = Message{
      Name:      "demo",
      TimeStamp: &amp;timestamp.Timestamp{Seconds: int64(time.Now().Second())},
  }
  
  //func TestGogoMessage_Marshal(t *testing.T) {
  //  myBytes, err := gogo.Marshal(&amp;msg)
  //  if err != nil {
  //      t.Fail()
  //  }
  
  //  _ = myBytes
  //}
  
  func TestProtoMessage_Marshal(t *testing.T) {
      myBytes, err := proto.Marshal(&amp;msg)
      if err != nil {
          t.Fail()
      }
  
      _ = myBytes
  }
  </code></pre>
  
  <p>compiled with:</p>
  
  <p><code>protoc --gofast_out=. ./demo/msg.proto</code> works, but running the test:</p>
  
  <pre><code># github.com/.../demo
  package github.com/.../demo (test)
      imports github.com/gogo/protobuf/proto: cannot find package "." in:
      /Users/.../vendor/github.com/gogo/protobuf/proto
  </code></pre>
  
  <p><code>protoc --go_out=. ./demo/msg.proto</code> works, but running the test:</p>
  
  <pre><code># github.com/.../demo [github.com/.../demo.test]
  ./msg.pb.go:127:28: m.TimeStamp.MarshalToSizedBuffer undefined (type *timestamp.Timestamp has no field or method MarshalToSizedBuffer)
  ./msg.pb.go:169:18: m.TimeStamp.Size undefined (type *timestamp.Timestamp has no field or method Size)
  ./msg.pb.go:277:25: m.TimeStamp.Unmarshal undefined (type *timestamp.Timestamp has no field or method Unmarshal)
  </code></pre>