Upgrade to Scala 2.12 #6691

wsargent · 2016-11-02T20:33:21Z

Sets up a Play version that works against 2.12.0 by default and does a cross-build to 2.11.8.

All the dependencies have been worked through, so if this builds, we should be good.

marcospereira · 2016-11-03T23:57:58Z

framework/project/plugins.sbt

@@ -16,7 +16,7 @@ logLevel := Level.Warn

 scalacOptions ++= Seq("-deprecation", "-language:_")

-addSbtPlugin("com.typesafe.play" % "interplay" % sys.props.getOrElse("interplay.version", "1.1.2"))
+addSbtPlugin("com.typesafe.play" % "interplay" % sys.props.getOrElse("interplay.version", "1.3.0-SNAPSHOT"))


Was version 1.3.0-SNAPSHOT published? Looks like the version was not changed at playframework/interplay#18.

Current master also shows that the last version still 1.2.1-SNAPSHOT:

https://github.com/playframework/interplay/blob/master/version.sbt

marcospereira · 2016-11-04T00:00:10Z

framework/project/build.properties

@@ -1,4 +1,4 @@
 #
 # Copyright (C) 2009-2016 Lightbend Inc. <https://www.lightbend.com>
 #
-sbt.version=0.13.11
+sbt.version=0.13.13


This should also be updated at other files (documentation, templates and subprojects).

I'll file a milestone issue for upgrading to sbt 0.13.13

schmitch · 2016-11-09T11:07:33Z

actually akka-http and akka-http-core are now released for 2.12 as 10.0.0-RC2.
Also sbt-io is also released: http://dl.bintray.com/typesafe/ivy-releases/org.scala-sbt/io_2.12/0.13.13/

Brings us down to our own dependencies.

wsargent · 2016-11-09T21:41:22Z

@schmitch great, I'll see about updating our internal docs...

wsargent · 2016-11-10T00:44:52Z

@schmitch okay, akka-http and sbt-io has been updated and play-doc 1.3.0 / interplay 1.7.0 has been released -- if this passes the build I think we're good.

schmitch · 2016-11-10T08:14:29Z

framework/project/BuildSettings.scala

@@ -56,6 +56,14 @@ object BuildSettings {
        Resolver.typesafeRepo("releases"),
        Resolver.typesafeIvyRepo("releases")
      ),
+      scalacOptions in(Compile, doc) := {


maybe we should use ++= instead of := and wrap it with .value, I told you to add it since I didn't found other occurences which might override that.

schmitch · 2016-11-10T09:13:24Z

Actually scripted tests will now only run on 2.12 and the normal tests won't actually cross-build as it seems. we need to adjust the travis build file.

Also scripted tests fail, two of them are easy to fix:

Fix for the scripted tests:

diff --git a/framework/src/sbt-plugin/src/sbt-test/routes-compiler-plugin/injected-routes-compilation/app/controllers/Application.scala b/framework/src/sbt-plugin/src/sbt-test/routes-compiler-plugin/injected-routes-compilation/app/controllers/Application.scala
index 5e97254..6e6a816 100644
--- a/framework/src/sbt-plugin/src/sbt-test/routes-compiler-plugin/injected-routes-compilation/app/controllers/Application.scala
+++ b/framework/src/sbt-plugin/src/sbt-test/routes-compiler-plugin/injected-routes-compilation/app/controllers/Application.scala
@@ -4,7 +4,7 @@
 package controllers

 import play.api.mvc._
-import scala.collection.JavaConversions._
+import scala.collection.JavaConverters._
 import javax.inject.Inject

 class Application @Inject() (c: ControllerComponents) extends AbstractController(c) {
@@ -36,7 +36,7 @@ class Application @Inject() (c: ControllerComponents) extends AbstractController
     Ok(`b[]`mkString(",") + " " + `b%%`)
   }
   def takeJavaList(x: java.util.List[Integer]) = Action {
-    Ok(x.mkString(","))
+    Ok(x.asScala.mkString(","))
   }
   def urlcoding(dynamic: String, static: String, query: String) = Action {
     Ok(s"dynamic=$dynamic static=$static query=$query")
diff --git a/framework/src/sbt-plugin/src/sbt-test/routes-compiler-plugin/routes-compilation/app/controllers/Application.scala b/framework/src/sbt-plugin/src/sbt-test/routes-compiler-plugin/routes-compilation/app/controllers/Application.scala
index 40cd0b0..8ce048f 100644
--- a/framework/src/sbt-plugin/src/sbt-test/routes-compiler-plugin/routes-compilation/app/controllers/Application.scala
+++ b/framework/src/sbt-plugin/src/sbt-test/routes-compiler-plugin/routes-compilation/app/controllers/Application.scala
@@ -5,7 +5,7 @@ package controllers

 import play.api.mvc._
 import javax.inject.Inject
-import scala.collection.JavaConversions._
+import scala.collection.JavaConverters._

 class Application @Inject() (c: ControllerComponents) extends AbstractController(c) {
   def index = Action {
@@ -30,7 +30,7 @@ class Application @Inject() (c: ControllerComponents) extends AbstractController
     Ok(x.mkString(","))
   }
   def takeJavaList(x: java.util.List[Integer]) = Action {
-    Ok(x.mkString(","))
+    Ok(x.asScala.mkString(","))
   }
   def urlcoding(dynamic: String, static: String, query: String) = Action {
     Ok(s"dynamic=$dynamic static=$static query=$query")

after that we get a really strange failure of akka-http-server:
[error] (Play-Akka-Http-Server-Experimental/*:scripted) java.lang.NoSuchMethodError: scala.Predef$.refArrayOps([Ljava/lang/Object;)Lscala/collection/mutable/ArrayOps;
with a stack trace that is hard to guess, where the actual error really is.

wsargent · 2016-11-10T17:44:18Z

@schmitch I suspect that is happening from

https://github.com/sbt/sbt/blob/0.13.13_2.12cross/scripted/sbt/src/main/scala/sbt/test/ScriptedTests.scala#L180

wsargent · 2016-11-10T17:51:40Z

More update: when I run bin/testSbtPlugins, I run into https://issues.scala-lang.org/browse/SI-10027 (closed in 2.12.1)

[warn] /home/wsargent/work/playframework/upgrade-2.12/framework/src/play-docs/src/main/scala/play/docs/DocumentationHandler.scala:30: constructor PlayDoc in class PlayDoc is deprecated (since 1.3.0): Use the primary constructor
[warn]     new PlayDoc(repo, repo, "resources", PlayVersion.current, PageIndex.parseFrom(repo, "Home", Some("manual")), "Next")
[warn]     ^
[warn] one warning found
java.lang.StackOverflowError
    at scala.tools.nsc.util.JavaCharArrayReader.next(JavaCharArrayReader.scala:28)
    at scala.tools.nsc.javac.JavaScanners$JavaScanner.putCommentChar(JavaScanners.scala:580)
    at scala.tools.nsc.javac.JavaScanners$JavaScanner.skipBlockComment(JavaScanners.scala:585)

schmitch · 2016-11-10T18:03:21Z

yeah but actually that can be fixed with higher JAVA_OPTS, i use:

export JAVA_OPTS="-Xmx4G -Xss2M -XX:MaxMetaspaceSize=512M -XX:ReservedCodeCacheSize=512M -Dfile.encoding=UTF-8"

wsargent · 2016-11-10T18:04:34Z

@schmitch we only have 3GB on the Travis CI box, but we can start there...

wsargent · 2016-11-10T22:08:54Z

The scripted error seems to be happening because of the sbt mediator. There's a workaround: sbt/sbt#2786 (comment)

There are a couple of scaladoc errors resulting from scaladoc complaining that private Java classes are escaping their boundaries -- they've been made package private.

The stackoverflow https://issues.scala-lang.org/browse/SI-10027 only occurs in Play-Java, so I've pointed Play-Java project to the Scala 2.12 nightly build just to get something working.

wsargent · 2016-11-11T02:41:36Z

Well, I can get most of the scripted tests working with MediatorWorkaround, but the Akka-Http-Server tests are still failing regardless:

> project Play-Akka-Http-Server-Experimental
> scripted
[info] Wrote /home/wsargent/work/playframework/upgrade-2.12/framework/src/play-akka-http-server/target/scala-2.12/play-akka-http-server-experimental_2.12-2.6.0-SNAPSHOT.pom
[info] :: delivering :: com.typesafe.play#play-akka-http-server-experimental_2.12;2.6.0-SNAPSHOT :: 2.6.0-SNAPSHOT :: integration :: Thu Nov 10 18:37:27 PST 2016
[info]  delivering ivy file to /home/wsargent/work/playframework/upgrade-2.12/framework/src/play-akka-http-server/target/scala-2.12/ivy-2.6.0-SNAPSHOT.xml
[info] Formatting 1 Scala source {file:/home/wsargent/work/playframework/upgrade-2.12/framework/}Play(compile) ...
[info] Reformatted 1 Scala source {file:/home/wsargent/work/playframework/upgrade-2.12/framework/}Play(compile).
[info] Packaging /home/wsargent/work/playframework/upgrade-2.12/framework/src/play-akka-http-server/target/scala-2.12/play-akka-http-server-experimental_2.12-2.6.0-SNAPSHOT.jar ...
[info] Done packaging.
[info]  published play-akka-http-server-experimental_2.12 to /home/wsargent/.ivy2/local/com.typesafe.play/play-akka-http-server-experimental_2.12/2.6.0-SNAPSHOT/poms/play-akka-http-server-experimental_2.12.pom
[info]  published play-akka-http-server-experimental_2.12 to /home/wsargent/.ivy2/local/com.typesafe.play/play-akka-http-server-experimental_2.12/2.6.0-SNAPSHOT/jars/play-akka-http-server-experimental_2.12.jar
[info]  published ivy to /home/wsargent/.ivy2/local/com.typesafe.play/play-akka-http-server-experimental_2.12/2.6.0-SNAPSHOT/ivys/ivy.xml
[trace] Stack trace suppressed: run last Play-Akka-Http-Server-Experimental/*:scripted for the full output.
[error] (Play-Akka-Http-Server-Experimental/*:scripted) java.lang.NoSuchMethodError: scala.Predef$.refArrayOps([Ljava/lang/Object;)Lscala/collection/mutable/ArrayOps;
[error] Total time: 0 s, completed Nov 10, 2016 6:37:27 PM

https://github.com/wsargent/playframework/blob/upgrade-2.12/framework/src/play-akka-http-server/src/sbt-test/akka-http/play-akka-http-plugin/project/MediatorWorkaround.scala

schmitch · 2016-11-11T08:08:42Z

Might be a different error?

gmethvin · 2016-11-27T01:13:50Z

What's the status of this PR? Are we ready to merge soon?

Also it looks to me we could backport to 2.5.x as well (perhaps with different dependency versions for Scala 2.12).

wsargent · 2016-11-28T00:33:35Z

There's a couple of tests involving Akka-HTTP that don't resolve and have been disabled. Otherwise, it's good for review.

wsargent · 2016-11-28T00:34:37Z

framework/build.sbt

@@ -104,7 +104,7 @@ lazy val PlayAkkaHttpServerProject = PlayCrossBuiltProject("Play-Akka-Http-Serve
    .settings(libraryDependencies ++= akkaHttp)
    // Include scripted tests here as well as in the SBT Plugin, because we
    // don't want the SBT Plugin to have a dependency on an experimental module.
-    .settings(playFullScriptedSettings: _*)
+    //.settings(ScriptedPlugin.scriptedSettings ++ playScriptedSettings)


Commented out because the sbt-mediator throws exception here even if there are no sbt scripted tests...

wsargent · 2016-11-29T04:37:07Z

framework/src/play/src/main/scala/play/api/mvc/Action.scala

@@ -122,7 +122,8 @@ trait Action[A] extends EssentialAction {
 * @tparam A the body content type
 */
 trait BodyParser[+A] extends (RequestHeader => Accumulator[ByteString, Either[Result, A]]) {
-  self =>
+  // "with Any" because we need to prevent 2.12 SAM inference here
+  self: BodyParser[A] with Any =>


Scala 2.12 looks at Function types and attempts to convert them to JDK 1.8 SAM types -- since BodyParser extends Function1, it ends up conflicting with the other Action.apply method that takes only a (Request[A] => Result) (and therefore is also a SAM type, but does not share a common base type).

The solution here is to ensure the BodyParser cannot be treated as a SAM type by the compiler, by kludging the explicit self type reference.

wsargent · 2016-11-29T04:37:40Z

documentation/manual/working/commonGuide/filters/SecurityHeaders.md

@@ -25,7 +25,7 @@ play.http.filters = "filters.MyFilters"

 ## Configuring the security headers

-Scaladoc is available in the [play.filters.headers](api/scala/play/filters/headers/package.html) package.
+Scaladoc is available in the [play.filters.headers](api/scala/play/filters/headers/) package.


2.12 doesn't believe in package.html

wsargent · 2016-11-29T04:38:58Z

...orking/commonGuide/filters/code/detailedtopics/configuration/gzipencoding/CustomFilters.java

        GzipFilter gzipFilter = new GzipFilter(
-          new GzipFilterConfig().withShouldGzip((req, res) ->
+          gzipFilterConfig.withShouldGzip((BiFunction<Http.RequestHeader, Result, Object>) (req, res) ->


GzipFilterConfig has two withShouldGzip, both of which equate to SAM types. The 2.12 compiler can't distinguish, so we need an explicit cast here.

It might be a better idea to remove one of these methods or move the methods out to different classes altogether for Java API / Scala API.

Yeah, it's a shame we have to support Scala 2.11 too.

Maybe for Play 2.6 we should rename the Java one to something like withShouldGzipJava, then we can remove it when we drop support for 2.11. Most Java users should be able to upgrade to Scala 2.12 pretty easily so they'll be able to use the Scala function version.

what about creating two source folders one for 2.11 and one for 2.12 and keep the old version as is and the new version for 2.12 won't have two functions?

gmethvin · 2016-11-30T03:22:30Z

💯 👍 😄

ghost · 2016-11-30T20:24:02Z

Is this going to be released soon? Would be totally awesome! :)

rethab · 2016-12-08T06:21:21Z

@gmethvin is the backport going to happen? Or, what's holding it back?

wsargent · 2016-12-08T18:55:18Z

@RookieMaus Play 2.6.x is scheduled for Q1 2017 -- see https://docs.google.com/document/d/11sVi1-REAIDFVHvwBrfRt1uXkBzROHQYgmcZNGJtDnA/edit#

@rethab Getting 2.6.x out the door is the priority now.

jroper · 2017-02-09T04:27:21Z

With regards to backporting to 2.5, I can't see anything about this PR that is not binary compatible, or can't be made to be binary compatible.

The only change to public API is that BodyParser now has an Any self type. This has no impact on binary compatibility as self types are erased at runtime and only read by the compiler, and since Scala 2.11 doesn't ever generate lambdas, it should have zero impact on source compatibility.

There are several upgrades to libraries that may be binary incompatible, but that's easy to deal with in sbt where you can control the version pulled in based on the Scala version. There don't seem to be any changes that are dependent on those upgrades.

Nearly all the changes in this PR are related to testing and docs, and so should be innocuous to backport.

schmitch · 2017-02-10T08:07:10Z

Well to bring 2.12 to 2.5 we would eat least need to have a version of twirl and play-doc that is binary compatible, or is there a way to change sbt plugins based on scala version?
Another problem might be to actually have a 2.12 build that works around fork run, but I guess it's possible to disable it for 2.12

marcospereira reviewed Nov 3, 2016

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schmitch mentioned this pull request Nov 4, 2016

Cross build for Scala 2.12 #6110

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KarelCemus mentioned this pull request Nov 6, 2016

Scala 2.12 KarelCemus/play-redis#69

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wsargent force-pushed the upgrade-2.12 branch from cfdd26a to ba00881 Compare November 10, 2016 00:40

wsargent changed the title ~~WIP - Upgrade to Scala 2.12~~ Upgrade to Scala 2.12 Nov 10, 2016

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wsargent force-pushed the upgrade-2.12 branch from ba00881 to 965de16 Compare November 10, 2016 22:05

wsargent force-pushed the upgrade-2.12 branch 2 times, most recently from c3bf287 to 985e398 Compare November 11, 2016 01:01

wsargent force-pushed the upgrade-2.12 branch 2 times, most recently from 2ee4e03 to 8a87fd8 Compare November 17, 2016 01:09

vmunier mentioned this pull request Nov 21, 2016

V 1.1.0 Induces a fatal run-time error vmunier/scalajs-scripts#14

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jroper mentioned this pull request Nov 21, 2016

Add Scala API lagom/lagom#1

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wsargent added 4 commits November 21, 2016 17:30

Upgrades various dependencies for 2.12

3b2ed65

Apply Application fixes

b2c70f7

Add mediator workaround

b8b652c

Add mediator workaround to akka-http-server

7dfa750

wsargent force-pushed the upgrade-2.12 branch from 346e8a8 to 7dfa750 Compare November 22, 2016 01:47

Will Sargent and others added 5 commits November 21, 2016 20:16

Comment out akka-http scripted tests

9bde5d2

Update dependencies

dfeef64

Fix Scala 2.12 SAM inference

b39fe0f

Fix ambiguous documentation tests

92cc1c3

Change package.html to relative link

9a055e1

wsargent commented Nov 28, 2016

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gmethvin approved these changes Nov 30, 2016

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wsargent merged commit c9d2b33 into playframework:master Nov 30, 2016

wsargent deleted the upgrade-2.12 branch November 30, 2016 00:58

3tty0n mentioned this pull request Dec 3, 2016

Cross build to Scala 2.12 slack-scala-client/slack-scala-client#37

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adamvoss mentioned this pull request Jan 2, 2017

Update list of missing Scala 2.12 dependencies scalacenter/scaladex#318

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SethTisue mentioned this pull request Aug 25, 2021

Drop Scala 2.12 and sbt 1.3 (and 0.13.x leftovers) #10956

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Upgrade to Scala 2.12 #6691

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