AshScriptPlugin uses bash syntax to process args

[gregsymons]

Expected behaviour

sbt docker:stage should generate an ash/dash compatible script in target/docker/stage/opt/docker/bin

Actual behaviour

The generated script contains syntax specific to bash (and other less posixy shells). Specifically, the generated process_args () function uses the [[ syntax for test, which is not available in strictly compliant shells like as ash and dash.

Information

• What sbt-native-packager are you using: 1.6.0
• What sbt version: 1.2.8
• What is your build system (e.g. Ubuntu, MacOS, Windows, Debian ): OS X and Ubuntu
• What package are you building: docker
• What version has your build tool:
  (this is my local version, but I've also seen it in our CI builds, which are Ubuntu-based, but run the same docker version)

Client: Docker Engine - Community
 Version:           19.03.5
 API version:       1.40
 Go version:        go1.12.12
 Git commit:        633a0ea
 Built:             Wed Nov 13 07:22:34 2019
 OS/Arch:           darwin/amd64
 Experimental:      false

Server: Docker Engine - Community
 Engine:
  Version:          19.03.5
  API version:      1.40 (minimum version 1.12)
  Go version:       go1.12.12
  Git commit:       633a0ea
  Built:            Wed Nov 13 07:29:19 2019
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          v1.2.10
  GitCommit:        b34a5c8af56e510852c35414db4c1f4fa6172339
 runc:
  Version:          1.0.0-rc8+dev
  GitCommit:        3e425f80a8c931f88e6d94a8c831b9d5aa481657
 docker-init:
  Version:          0.18.0
  GitCommit:        fec3683

• What is your target system: For the docker image, our base image is based off adoptopenjdk-13-bionic (though we execute the build with with the system openjdk 8 due to incompatibilities between our internal build plugin and sbt 1.3.x)

This is actually pretty easy to fix; it was brought in on #1255, and you can see it on line 61 and lines 83 and 84. Fortunately, if you don't have args to parse, or are running on a base image where /bin/sh really is bash, the script works fine, but if you need to parse args on ash/dash, I expect you will not get the desired behavior.

If I get the chance to later this week I'll try to open a PR for it, but thought I'd give ya'll a heads up.

[gregsymons]

This is probably related to #1264, since both issues look like they stem from the same commit.

[muuki88]

Thanks @gregsymons for your detailed issue 👍 Feel free to ask for any help on the PR 😄