First extract GH repo from upstream, then origin

Author: armanbilge

github/src/main/scala/org/typelevel/sbt/TypelevelGitHubPlugin.scala

@@ -58,19 +58,23 @@ object TypelevelGitHubPlugin extends AutoPlugin {
   private[sbt] def gitHubUserRepo = Def.setting {
     import scala.sys.process._
 
-    val identifier = """([^\/]+?)"""
-    val GitHubHttps = s"https://github.com/$identifier/$identifier(?:\\.git)?".r
-    val GitHubGit = s"git://github.com:$identifier/$identifier(?:\\.git)?".r
-    val GitHubSsh = s"[email protected]:$identifier/$identifier(?:\\.git)?".r
-    Try {
-      val remote = List("git", "ls-remote", "--get-url", "origin").!!.trim()
-      remote match {
-        case GitHubHttps(user, repo) => Some((user, repo))
-        case GitHubGit(user, repo) => Some((user, repo))
-        case GitHubSsh(user, repo) => Some((user, repo))
-        case _ => None
-      }
-    }.toOption.flatten
+    def fromRemote(remote: String) = {
+      val identifier = """([^\/]+?)"""
+      val GitHubHttps = s"https://github.com/$identifier/$identifier(?:\\.git)?".r
+      val GitHubGit = s"git://github.com:$identifier/$identifier(?:\\.git)?".r
+      val GitHubSsh = s"[email protected]:$identifier/$identifier(?:\\.git)?".r
+      Try {
+        List("git", "ls-remote", "--get-url", remote).!!.trim() match {
+          case GitHubHttps(user, repo) => Some((user, repo))
+          case GitHubGit(user, repo) => Some((user, repo))
+          case GitHubSsh(user, repo) => Some((user, repo))
+          case _ => None
+        }
+      }.toOption.flatten
+    }
+
+    // upstream if this is a fork, otherwise fallback to origin
+    fromRemote("upstream").orElse(fromRemote("origin"))
   }
 
 }