[2.8.x] Calling setScalaVersionFromSbtVersion in test-scripted is totally useless

[mkurz]

In the 2.8.x branch we run scripted tests against sbt 0.13.x and 1.2.x:

playframework/.travis.yml

Lines 72 to 73 in 417fe4c

	name: "Run scripted tests (a) for sbt 0.13.x"
	script: scripts/test-scripted 0.13.x 'play-sbt-plugin/*1of3'

playframework/.travis.yml

Lines 84 to 85 in 417fe4c

	- name: "Run scripted tests (a) for sbt 1.x"
	script: scripts/test-scripted 1.x 'play-sbt-plugin/*1of3'

test-scripted calls setScalaVersionFromSbtVersion:

playframework/scripts/test-scripted

Lines 8 to 16 in 417fe4c

	SBT_VERSION="${1:-1.x}"
	shift
	setScalaVersionFromSbtVersion
	cd "$BASEDIR"
	start scripted "RUNNING SCRIPTED TESTS FOR SBT $SBT_VERSION"
	runSbt "++$SCALA_VERSION" "Sbt-Plugin/scripted $@"
	end scripted "ALL SCRIPTED TESTS PASSED"

playframework/scripts/scriptLib

Lines 72 to 78 in 417fe4c

	setScalaVersionFromSbtVersion() {
	case "$SBT_VERSION" in
	1*) SCALA_VERSION="2.12.10" ;;
	0.13*) SCALA_VERSION="2.10.7" ;;
	*) echo "Aborting: Failed to determine scala version for sbt $SBT_VERSION" >&2; exit 1 ;;
	esac
	}

So this ends up in either

• runSbt "++2.12.10" "Sbt-Plugin/scripted $@" when passed 1.x to the script, or
• runSbt "++2.10.7" "Sbt-Plugin/scripted $@" when passed 0.13.x to the script

Turns out this is totally useless. I mean, yes sbt will start with the scala version specified... BUT all, absolutly all, scripted test projects define their own scala version by setting it via the scala.version property:

playframework/dev-mode/sbt-plugin/src/sbt-test/play-sbt-plugin/akka-fork-join-pool/build.sbt

Line 12 in 417fe4c

scalaVersion := sys.props("scala.version"),

Means that all sbt scripted projects launch with the scala version which gets set here:

playframework/project/BuildSettings.scala

Line 294 in 417fe4c

s"-Dscala.version=$scala212",

which is the value from interplay...

Also... of course Play 2.8.x is not even published for Scala 2.10, so if 2.10.7, really would get used it would fail badly...

I am pretty sure this is a left over from the Play 2.7.x branch, because back then the "test-scripted" script, which actually were 2 scripts, did also run publishLocal and of course for this it had to publish the Play sbt plugin for Scala 2.10 as well to support sbt 0.13.x:

playframework/scripts/test-sbt-plugins-0_13

Lines 8 to 14 in d09e2f0

	SCALA_VERSION="2.10.6"
	SBT_VERSION="0.13"
	cd "$BASEDIR"
	printMessage "PUBLISHING PLAY LOCALLY FOR SBT ${SBT_VERSION}"
	runSbt ++${SCALA_VERSION} quickPublish publishLocal

playframework/scripts/test-sbt-plugins-1_0

Lines 8 to 14 in d09e2f0

	SCALA_VERSION="2.12.9"
	SBT_VERSION="1.2.8"
	cd "$BASEDIR"
	printMessage "PUBLISHING PLAY LOCALLY FOR SBT ${SBT_VERSION}"
	runSbt ++${SCALA_VERSION} quickPublish publishLocal

So now that's why in #10655 I added a very stupid scripted test which just prints the scala and sbt version to the console so we can easily check in Travis which versions were actually used to run the scripted tests:
https://github.com/playframework/playframework/pull/10655/files#diff-660cf244988ca8b1705f1b3cb675d9e0750c7f5c86c7fecb2274f0deb842b36d

BTW: In master branch this setScalaVersionFromSbtVersion does not exist anymore... (because we dropped sbt 0.13.x)