Okhttp: Intercepter-logging: wrong protocol for real server using http2

[Tvede-dk]

What kind of issue is this?

• [X] Bug report.

Summary

• when using OkHttp with an HTTP2 server, the logging generated by logging-interceptor is wrong with regards to the protocol. it prints "http/1.1" when in reality it is "h2"
  (since in line https://github.com/square/okhttp/blob/a94f952d4fd612b649f0e1afbbcd06b7b991765b/okhttp/src/main/java/okhttp3/RealCall.java#L184 the connection is null, the connection will be null in
  https://github.com/square/okhttp/blob/master/okhttp-logging-interceptor/src/main/java/okhttp3/logging/HttpLoggingInterceptor.java#L154 , thus the result will be "http/1.1", which is extremely confusing and wrong.)

• how to verify this is ? / reproduce this

Create a request to a http2 capable server, fire it off, and inspect the Response (there the protocol is set to "h2" as expected), and watch the interceptor log "http/1.1".

• Write a failing test:
  its properly more a definition of using http1.1 as a default value, instead of saying "we do not know".

[swankjesse]

Failing test?

[swankjesse]

Looking further, this is a problem with how the logging interceptor should behave when the protocol version is unknown? Yeah, we can fix this.