Initial support for handling build matrices

I'm sure there are lots of semantics I'm not considering with, for
example:

* folding build matrix includes with root scala versions
* matrix excludes?
* etc

But for now this solves the build matrix I created in scala/scala-abide.

Fixes #2

README.md

@@ -26,10 +26,6 @@ Other than that, as `sbt-travisci` is an AutoPlugin that is all that is required
 
 `crossScalaVersions in ThisBuild` will be automatically set to the scala versions in `.travis.yml`.
 
-**NOTE**: It currently doesn't support build matrices ([#2][]).
-
-[#2]: https://github.com/dwijnand/sbt-travisci/issues/2
-
 ## Dependencies
 
 Depends on the presence of a `.travis.yml` file at the root of the project.

notes/1.0.0.markdown

@@ -1,6 +1,2 @@
 - Initial implementation.
 - `crossScalaVersions in ThisBuild` will be automatically set to the scala versions in `.travis.yml`.
-
-**NOTE**: It currently doesn't support build matrices ([#2][]).
-
-[#2]: https://github.com/dwijnand/sbt-travisci/issues/2

src/main/scala/sbttravisci/TravisCiPlugin.scala

@@ -9,16 +9,28 @@ object TravisCiPlugin extends AutoPlugin {
     // parses Scala versions out of .travis.yml (doesn't support build matrices)
     crossScalaVersions := {
       import scala.collection.JavaConverters._
-      Using.fileInputStream(baseDirectory.value / ".travis.yml")(fis =>
-        Option(new org.yaml.snakeyaml.Yaml().load(fis))
-          .collect { case map: java.util.Map[_, _] => Option(map get "scala") }
-          .flatten
+      Using.fileInputStream(baseDirectory.value / ".travis.yml") { fis =>
+        val yaml = Option(new org.yaml.snakeyaml.Yaml().load(fis))
+          .collect { case map: java.util.Map[_, _] => map }
+
+        def fromRoot = yaml
+          .flatMap(map => Option(map get "scala"))
           .collect {
             case versions: java.util.List[_] => versions.asScala.toList map (_.toString)
             case version: String             => version :: Nil
           }
-          .getOrElse(List(scalaVersion.value))
-      )
+
+        def fromMatrixInclude = yaml
+          .flatMap(map => Option(map get "matrix"))
+          .collect { case map: java.util.Map[_, _] => Option(map get "include") }.flatten
+          .collect { case versions: java.util.List[_] =>
+            versions.asScala.toList.collect { case map: java.util.Map[_, _] =>
+              Option(map get "scala") map (_.toString)
+            }.flatten
+          }
+
+        fromMatrixInclude orElse fromRoot getOrElse List(scalaVersion.value)
+      }
     }
   )
 }

src/sbt-test/travisci/build-matrix/.travis.yml

@@ -0,0 +1,9 @@
+language: scala
+matrix:
+  include:
+   - scala: 2.10.6
+     jdk: openjdk6
+   - scala: 2.11.8
+     jdk: openjdk6
+   - scala: 2.12.0
+     jdk: oraclejdk8

src/sbt-test/travisci/build-matrix/build.sbt

@@ -0,0 +1,3 @@
+def check[A](inc: A, exp: A) = assert(inc == exp, s"Versions mismatch: Expected $exp, Incoming $inc")
+
+TaskKey[Unit]("check") := check(crossScalaVersions.value, Seq("2.10.6", "2.11.8", "2.12.0"))

src/sbt-test/travisci/build-matrix/project/plugins.sbt

@@ -0,0 +1,5 @@
+sys.props.get("plugin.version") match {
+  case Some(x) => addSbtPlugin("com.dwijnand" % "sbt-travisci" % x)
+  case _       => sys.error("""|The system property 'plugin.version' is not defined.
+                               |Specify this property using the scriptedLaunchOpts -D.""".stripMargin)
+}

src/sbt-test/travisci/build-matrix/test

@@ -0,0 +1 @@
+> check