Add runtime_jdk to scala_binary (#1380)

* Add runtime_jdk to scala_binary

Author: wiwa

scala/private/rules/scala_binary.bzl

@@ -52,6 +52,10 @@ _scala_binary_attrs = {
     "main_class": attr.string(mandatory = True),
     "classpath_resources": attr.label_list(allow_files = True),
     "jvm_flags": attr.string_list(),
+    "runtime_jdk": attr.label(
+        default = Label("@bazel_tools//tools/jdk:current_java_runtime"),
+        providers = [java_common.JavaRuntimeInfo],
+    ),
 }
 
 _scala_binary_attrs.update(launcher_template)

test/BUILD

@@ -471,8 +471,17 @@ scala_specs2_junit_test(
     "//test/src/main/scala/scalarules/test/twitter_scrooge:justscrooge2b_binary",
     "//test/src/main/scala/scalarules/test/large_classpath:largeClasspath",
     "//test:test_scala_proto_server",
+    "//test:scala_binary_jdk_11",
 ]]
 
+# Make sure scala_binary respects runtime_jdk on bazel run
+scala_binary(
+    name = "scala_binary_jdk_11",
+    srcs = ["ScalaBinaryJdk11.scala"],
+    main_class = "scalarules.test.ScalaBinaryJdk11",
+    runtime_jdk = "@bazel_tools//tools/jdk:remote_jdk11",
+)
+
 # Generate a file containing the rootpaths of a Scala binary.
 genrule(
     name = "rootpath-script",

test/ScalaBinaryJdk11.scala

@@ -0,0 +1,11 @@
+package scalarules.test
+
+object ScalaBinaryJdk11 {
+  def main(args: Array[String]): Unit = {
+    val expectedMajorVersion = "11";
+    val version = System.getProperty("java.version");
+    val majorVersionMatches = version.startsWith(expectedMajorVersion + ".");
+    val failureMsg = "Expected major version of " + expectedMajorVersion + " but got version: " + version;
+    require(majorVersionMatches, failureMsg);
+  }
+}