can't override isChanging for SNAPSHOT dependencies

[OlegYch]

some dependencies are not actually snapshots, even though they have SNAPSHOT in their name
e.g. http://repo.typesafe.com/typesafe/simple/maven-snapshots/com/typesafe/play/play_2.10/
i reported this at
playframework/playframework#2553
and tried to workaround with

//val playVersion = "2.2.2"
val playVersion = "2.3-2014-03-27-2e87b7e-SNAPSHOT"

addSbtPlugin("com.typesafe.play" % "sbt-plugin" % playVersion)

allDependencies := allDependencies.value.map(m => if (m.revision == playVersion) m.copy(isChanging = false) else m)

but this doesn't seem to work (using sbt 0.13.2-M2, can't update atm because of sbt/sbt-native-packager#197 )
additionally, i get

[info] downloading http://repo.typesafe.com/typesafe/snapshots/com/typesafe/play/play_2.10/2.3-2014-03-27-2e87b7e-SNAPSHOT/play_2.10-2.3-2014-03-27-2e87b7e-SNAPSHOT.jar ...
[info]  [SUCCESSFUL ] com.typesafe.play#play_2.10;2.3-2014-03-27-2e87b7e-SNAPSHOT!play_2.10.jar (17194ms)
etc

every time i update, even though there is no way the dependency has changed

[OlegYch]

even with 0.13.2-RC1 and clean cache i get
[error] Couldn't delete outdated artifact from cache: C:\Users\OlegYch.ivy2\cache\com.typesafe.play\sbt-link\jars\sbt-link-2.3-2014-03-27-2e87b7e-SNAPSHOT.jar

[OlegYch]

when i look into c:\Users\OlegYch.ivy2\cache\com.typesafe.play\sbt-link\ivy-2.3-2014-03-27-2e87b7e-SNAPSHOT.xml i see that "publication" changes every time!

[eed3si9n]

From sbt's point of view, if your version includes "-SNAPSHOT" it's a changing snapshot. As @jsuereth wrote, Play should avoid appending "-SNAPSHOT" to avoid it being treated as changing.

Whether it should be downloading or not is a whole another story. I'm closing this case as "by-design" for now.

[OlegYch]

isChanging should probably take precedence over whatever heuristic is employed, don't you think?

[eed3si9n]

I don't think so. If I understand correctly, isChanging is a Boolean not an Option[Boolean], so it being false mostly means the build user didn't specify changing(). In that case, we need to assume everything that contains the word "-SNAPSHOT" is changing.

[jsuereth]

Hmm, there's also isSnapshot in the build, which is meant to do the same thing as "changing" for the local project.