Adds envVars propagation client -> server

Since Mill now executes in a long-lived JVM, the builds do not have a
chance to use environment variables as inputs. This propagates the
environment variables from the client all the way down to the context
available to the tasks as a `Map[String, String]` so that they can be
used as inputs should the user choose to do so.

https://github.com/lihaoyi/mill/issues/257

3 files changed, 20 insertions, 9 deletions

diff --git a/main/src/mill/Main.scala b/main/src/mill/Main.scala
index e026dfe0..c9ec00ca 100644
--- a/main/src/mill/Main.scala
+++ b/main/src/mill/Main.scala
@@ -2,6 +2,8 @@ package mill
 
 import java.io.{InputStream, PrintStream}
 
+import scala.collection.JavaConverters._
+
 import ammonite.main.Cli._
 import ammonite.ops._
 import ammonite.util.Util
@@ -16,13 +18,15 @@ object ServerMain extends mill.clientserver.ServerMain[Evaluator.State]{
             mainInteractive: Boolean,
             stdin: InputStream,
             stdout: PrintStream,
-            stderr: PrintStream) = Main.main0(
+            stderr: PrintStream,
+            env : Map[String, String]) = Main.main0(
     args,
     stateCache,
     mainInteractive,
     DummyInputStream,
     stdout,
-    stderr
+    stderr,
+    env
   )
 }
 object Main {
@@ -38,7 +42,8 @@ object Main {
       ammonite.Main.isInteractive(),
       System.in,
       System.out,
-      System.err
+      System.err,
+      System.getenv().asScala.toMap
     )
     System.exit(if(result) 0 else 1)
   }
@@ -48,7 +53,8 @@ object Main {
             mainInteractive: Boolean,
             stdin: InputStream,
             stdout: PrintStream,
-            stderr: PrintStream): (Boolean, Option[Evaluator.State]) = {
+            stderr: PrintStream,
+            env: Map[String, String]): (Boolean, Option[Evaluator.State]) = {
     import ammonite.main.Cli
 
     val removed = Set("predef-code", "no-home-predef")
@@ -116,7 +122,8 @@ object Main {
           val runner = new mill.main.MainRunner(
             config.copy(colored = Some(mainInteractive)),
             stdout, stderr, stdin,
-            stateCache
+            stateCache,
+            env
           )
 
           if (mill.clientserver.ClientServer.isJava9OrAbove) {
diff --git a/main/src/mill/main/MainRunner.scala b/main/src/mill/main/MainRunner.scala
index efebd5a5..fed664fd 100644
--- a/main/src/mill/main/MainRunner.scala
+++ b/main/src/mill/main/MainRunner.scala
@@ -20,7 +20,8 @@ class MainRunner(val config: ammonite.main.Cli.Config,
                  outprintStream: PrintStream,
                  errPrintStream: PrintStream,
                  stdIn: InputStream,
-                 stateCache0: Option[Evaluator.State] = None)
+                 stateCache0: Option[Evaluator.State] = None,
+                 env : Map[String, String])
   extends ammonite.MainRunner(
     config, outprintStream, errPrintStream,
     stdIn, outprintStream, errPrintStream
@@ -75,7 +76,8 @@ class MainRunner(val config: ammonite.main.Cli.Config,
             errPrintStream,
             errPrintStream,
             stdIn
-          )
+          ),
+          env
         )
 
         result match{
diff --git a/main/src/mill/main/RunScript.scala b/main/src/mill/main/RunScript.scala
index 77930cc8..75042dea 100644
--- a/main/src/mill/main/RunScript.scala
+++ b/main/src/mill/main/RunScript.scala
@@ -29,7 +29,8 @@ object RunScript{
                 instantiateInterpreter: => Either[(Res.Failing, Seq[(Path, Long)]), ammonite.interp.Interpreter],
                 scriptArgs: Seq[String],
                 stateCache: Option[Evaluator.State],
-                log: Logger)
+                log: Logger,
+                env : Map[String, String])
   : (Res[(Evaluator[Any], Seq[PathRef], Either[String, Seq[Js.Value]])], Seq[(Path, Long)]) = {
 
     val (evalState, interpWatched) = stateCache match{
@@ -53,7 +54,8 @@ object RunScript{
 
     val evalRes =
       for(s <- evalState)
-      yield new Evaluator[Any](home, wd / 'out, wd / 'out, s.rootModule, log, s.classLoaderSig, s.workerCache)
+      yield new Evaluator[Any](home, wd / 'out, wd / 'out, s.rootModule, log,
+        s.classLoaderSig, s.workerCache, env)
 
     val evaluated = for{
       evaluator <- evalRes