Cannot resolve an SBT plugin published to a maven repo - sbt

Question

I created a reproducible example about a problem I'm experiencing with SBT plugin resolution:
https://github.com/NicolasRouquette/sbt.problem.example
This example has two SBT projects:
test.plugin a simple SBT plugin
test.app a simple SBT project that uses the test.plugin
There is also a local Maven repository to which the test.plugin is published with a POM file that includes properties like this:
<properties>
<git.branch>master</git.branch>
<git.commit>fe2dc11d6fbb85c5ce0e83b031bbd425997bbd59</git.commit>
<git.tags></git.tags>
</properties>
<properties>
<scalaVersion>2.10</scalaVersion>
<sbtVersion>0.13</sbtVersion>
<extraDependencyAttributes xml:space="preserve">+e:sbtVersion:###:+0.13:###:+module:###:+sbt-license plugin:###:+e:scalaVersion:###:+2.10:###:+organisation:###:+com.banno:###:+branch:###:+##:NULL:##:###:+revision:###:+0.1.5:###:
+e:sbtVersion:###:+0.13:###:+module:###:+sbt-license-report:###:+e:scalaVersion:###:+2.10:###:+organisation:###:+com.typesafe.sbt:###:+branch:###:+##:NULL:##:###:+revision:###:+1.0.0:###:
+e:sbtVersion:###:+0.13:###:+module:###:+sbt-git:###:+e:scalaVersion:###:+2.10:###:+organisation:###:+com.typesafe.sbt:###:+branch:###:+##:NULL:##:###:+revision:###:+0.8.5:###:
+e:sbtVersion:###:+0.13:###:+module:###:+aether-deploy:###:+e:scalaVersion:###:+2.10:###:+organisation:###:+no.arktekk.sbt:###:+branch:###:+##:NULL:##:###:+revision:###:+0.16:###:
</extraDependencyAttributes>
</properties>
I can't run SBT on test.app because SBT fails to resolve the test.plugin:
addSbtPlugin("org.test" % "test-plugin" % "1.0")
[warn] ::::::::::::::::::::::::::::::::::::::::::::::
[warn] :: UNRESOLVED DEPENDENCIES ::
[warn] ::::::::::::::::::::::::::::::::::::::::::::::
[warn] :: org.test#test-plugin;1.0: not found
[warn] ::::::::::::::::::::::::::::::::::::::::::::::
[warn]
[warn] Note: Some unresolved dependencies have extra attributes. Check that these dependencies exist with the requested attributes.
[warn] org.test:test-plugin:1.0 (sbtVersion=0.13, scalaVersion=2.10)
[warn]
[warn] Note: Unresolved dependencies path:
[warn] org.test:test-plugin:1.0 (sbtVersion=0.13, scalaVersion=2.10) (/opt/local/imce/users/nfr/github.imce/example/test.app/project/plugins.sbt#L6-7)
[warn] +- default:test-app-build:0.1-SNAPSHOT (sbtVersion=0.13, scalaVersion=2.10)
sbt.ResolveException: unresolved dependency: org.test#test-plugin;1.0: not found
at sbt.IvyActions$.sbt$IvyActions$$resolve(IvyActions.scala:294)
at sbt.IvyActions$$anonfun$updateEither$1.apply(IvyActions.scala:191)
at sbt.IvyActions$$anonfun$updateEither$1.apply(IvyActions.scala:168)
at sbt.IvySbt$Module$$anonfun$withModule$1.apply(Ivy.scala:155)
at sbt.IvySbt$Module$$anonfun$withModule$1.apply(Ivy.scala:155)
at sbt.IvySbt$$anonfun$withIvy$1.apply(Ivy.scala:132)
at sbt.IvySbt.sbt$IvySbt$$action$1(Ivy.scala:57)
...
Based on trying to understand what's going on with the debugger, I get the impression that:
resolving plugins happens very early when running SBT; which means that it involves a lot of SBT/Ivy machinery
I don't quite understand how the SBT/Ivy machinery resolves SBT plugins published to a Maven repository (though I've seen some kind of Maven/Ivy conversion somewhere)
it seems that the Maven POM properties are not analyzed to retrieve the sbtVersion (e.g. 0.13) and scalaBinaryVersion (e.g. 2.10) of an artifact
Can someone confirm/correct my analysis?
Is there a way to make this maven-published plugin dependency lookup work?

Answer 1

Thanks for the repro project.
First issue is that you have two <properties> element. sbt will use both the URL layout and the content of the POM to resolve the plugin. Here's how to merge <properties> element. Not sure if there's more elegant way:
makePom := {
val old = makePom.value
val pom = xml.XML.loadFile(old)
val additionalProperties =
(<git.branch>{git.gitCurrentBranch.value}</git.branch>
<git.commit>{git.gitHeadCommit.value.getOrElse("N/A")+(if (git.gitUncommittedChanges.value) "-SNAPSHOT" else "")}</git.commit>
<git.tags>{git.gitCurrentTags.value}</git.tags>)
val newPom = pom.copy(child = pom.child.toSeq map {
case elem: xml.Elem if elem.label == "properties" =>
elem.copy(child = elem.child ++ additionalProperties)
case x => x
})
xml.XML.save(old.toString, newPom, enc = "UTF-8", xmlDecl = true)
old
}
Next, you should've seen something like this when you tried to resolve the plugin:
[warn] ==== Local Test: tried
[warn] file:/xxx/sbt.problem.example/test.app/project/../local.repo/org/test/test-plugin_2.10_0.13/1.0/test-plugin-1.0.pom
See that test.app/project/../local.repo/ would become test.app/local.repo. Instead of ".." here's what you can do in test.app/project/plugins.sbt:
resolvers += new MavenCache("Local Test", baseDirectory.value.getParentFile.getParentFile / "local.repo")
addSbtPlugin("org.test" % "test-plugin" % "1.0")