Interpolates $MILL_VERSION in ivy imports (#649)

* Interpolates $MILL_VERSION in ivy imports

This overrides the default $ivy magic import by replacing the
`$MILL_VERSION` string with mill's version, in order to facilitate
the loading/update of contrib modules.

Ammonite had to be bumped to 1.6.9

* Removed bloop import

* AmmoniteExit import fix

* Removed repl dep check

* Removed problematic check

* Made ammonite version override-able

1 files changed, 18 insertions, 2 deletions

diff --git a/build.sc b/build.sc
index b95d46ac..ed5415f8 100755
--- a/build.sc
+++ b/build.sc
@@ -92,14 +92,30 @@ object main extends MillModule {
 
     def ivyDeps = Agg(
       // Keep synchronized with ammonite in Versions.scala
-      ivy"com.lihaoyi:::ammonite:1.6.7",
+      ivy"com.lihaoyi:::ammonite:1.6.9",
       // Necessary so we can share the JNA classes throughout the build process
       ivy"net.java.dev.jna:jna:4.5.0",
       ivy"net.java.dev.jna:jna-platform:4.5.0"
     )
 
     def generatedSources = T {
-      Seq(PathRef(shared.generateCoreSources(T.ctx().dest)))
+      val dest = T.ctx().dest
+      val version = publishVersion()
+      writeBuildInfo(dest, version)
+      shared.generateCoreSources(dest)
+      Seq(PathRef(dest))
+    }
+
+    def writeBuildInfo(dir : os.Path, version : String) = {
+      val code = s"""
+        |package mill
+        |
+        |object BuildInfo {
+        |  val millVersion = "$version"
+        |}
+      """.stripMargin.trim
+
+      os.write(dir / "BuildInfo.scala", code)
     }
   }