dockerLayerGrouping in Docker := (_ => None) does not work

[DieBauer]

Expected behaviour

dockerLayerGrouping in Docker  := (_ => None)

As described in the 1.7.0 release notes, disables layering of dependencies in 1/opt and 2/opt.

Actual behaviour

Still creates layer folders.

There is a test in https://github.com/sbt/sbt-native-packager/blob/master/src/sbt-test/docker/test-layer-groups/changes/nolayers.sbt

That does succeed, but that is not using the advertised dockerLayerGrouping but dockerGroupLayers. Changing this in the test to the advertised statement fails the test.

Is this a bug in the release notes, should it become dockerGroupLayers in Docker := PartialFunction.empty?

Information

• What sbt-native-packager are you using
  1.7.1
• What sbt version
  1.3.10
• What is your build system (e.g. Ubuntu, MacOS, Windows, Debian )
  Ubuntu and MacOS
• What package are you building (e.g. docker, rpm, ...)
  docker
• What version has your build tool (find out with e.g. rpm --version)
  RPM version 4.14.2.1
• What is your target system (e.g. Ubuntu 16.04, CentOS 7)
  CentOS8

[muuki88]

Thanks for reporting this along with providing a fix ♥️

Would you like to open a pull request and fix the docs? This has been introduced in a last pull request, which is hard to find on my phone 😅