Coveralls plugin incorrectly reports branch name as git commit hash

[siovene]

Expected vs Actual Behaviour

It should correctly report the branch name to Coveralls.

Instead it uses the hash of the current git commit.

Steps to Reproduce

With the following settings in build.sbt:

jacocoCoverallsJobId := {
  if (System.getenv("CI_BUILD_NUMBER") != null)
    System.getenv("CI_BUILD_NUMBER")
  else
    "Unknown build number"
}
jacocoCoverallsBuildNumber := Option(System.getenv("CI_BUILD_NUMBER"))
jacocoCoverallsPullRequest := Option(System.getenv("CI_PR_NUMBER"))
jacocoCoverallsRepoToken := Option(System.getenv("COVERALLS_REPO_TOKEN"))

the coveralls page reports the branch name as the current git commit, instead of the actual branch name. This makes it impossible to merge reports from multiple CI pipelines (e.g. our second pipeline is node/javascript using coveralls.js, which uses the correct branch name).

Environment

• SBT version: 1.2.7
• Plugin version: 3.1.0
• Scala version(s): 2.12.1
• Java version: 8