Add support for classes to @safeConfig.

[ClaireNeveu]

@balagez This PR extends the @safeConfig macro to work on classes so that it can be used with Play 2.4 (in light of scalamacros/paradise#49).

[ClaireNeveu]

Since the root object can now be defined as a member of the containing class/object we need to make this lazy so that it doesn't try to reference uninitialized values.

[balagez]

Running sbt test gives me a lot of compile errors like this one:

[error] ~/safe-config/src/test/scala/com/kinja/config/TestConfigs.scala:10: not found: value getConfig
[error]   private val subConfig = getConfig("sub-config")

[balagez]

I tried to make this work the way you described in the readme, but getting these compile errors:

[error] ~/kinja-service-template/app/dependencies/AppLoader.scala:27: not found: type Context
[error] class Bootstrap(context: Context) extends BuiltInComponentsFromContext(context) {
[error]                 ^
[error] ~/kinja-service-template/app/dependencies/AppLoader.scala:31: not found: value getString
[error]     val secret = getString("application.secret")
[error]                  ^
[error] two errors found

(FYI The code does work without the safeConfig annotation, so the imports are fine.)

Similarly, I experimented with the following code:

import com.typesafe.config.Config
import com.kinja.config.safeConfig

@safeConfig("rawConfig")
class AppConfig(private val rawConfig: Config) {

    val secret = getString("application.secret")
}

And got the same errors:

[error] ~/kinja-service-template/app/dependencies/AppConfig.scala:7: not found: type Config
[error] class AppConfig(private val rawConfig: Config) {
[error]                              ^
[error] ~/kinja-service-template/app/dependencies/AppConfig.scala:9: not found: value getString
[error]     val secret = getString("application.secret")
[error]                  ^
[error] two errors found

[ClaireNeveu]

@balagez sbt test works fine for me. Can you post the macro output in your failure?

[ClaireNeveu]

Nevermind, there was some weird caching going on that allowed it to succeed. I'm looking into those errors now.

[ClaireNeveu]

In retrospect, I didn't correctly handle class arguments and protected members when type-checking. Fix incoming.

[ClaireNeveu]

@balagez Please test again.

[balagez]

Works perfectly now.