Not a bug, but when someone in the #scala channel in IRC was complaining about:
"library.properties and compiler.properties were set to 2.9.2 unknown-unknown, which broke anything that did a version check", I pointed out this PKGBUILD, and jsuereth, the guy who does the official Scala builds, says that's not as tested and deviates slightly from the official release build. "I went to a lot of work to ensure the pre-built package is good enough for distros. I actually have my own re-packaging for deb/rpm here: https://github.com/scala/scala-dist/tree/master/installer";. He says about this PKGBUILD: "line 24 shoudl be dist-opt" ... "ant dist-opt -Dbuild.release=true"

Related chat log following: (WooLooWoo was the original complainer)
12:59 < jsuereth> pdxleif: Or I should say, it doesn't run tests
13:00 < jsuereth> line 24 shoudl be dist-opt
13:00 < pdxleif> I can file a bug report that they should run tests when building.
13:00 < jsuereth> pdxleif: That too
13:00 * pfn scratches his head some more
13:00 < jsuereth> pdxleif: Why don't they just use the one we build?
13:00 < pdxleif> I mostly use this as just a REPL to play around with - my building's done with SBT.
13:00 < jsuereth> pdxleif: In any case, there's also an issue of which JDK you're building with
13:00 < jsuereth> There are subtle bugs sometimes if you compile on JDK6 vs 7
13:00 < pdxleif> Dunno. They usually like to build things themselve (more control), but doesn't make a lot of sense for Java things.
13:01 < jsuereth> i.e. the standard library's bytecode is different from implicits and such
13:01 < jsuereth> pdxleif: I guess it's not terrible
13:01 < jsuereth> pdxleif: But it also wounds me a bit. I'm the one who builds and packages releases. DON'T YOU TRUST ME!!!?
13:01 < pdxleif> They have it depend on java 6
13:01 < jsuereth> pdxleif: Right, we build on JDK5
13:02 < jsuereth> or we did until recently
13:02 < jsuereth> Also, which JDK?
13:02 < jsuereth> cuz that can matter sometimes too
13:02 < jsuereth> IN any case, the biggest issue you have is you're not running the same version as everyone else
13:03 < jsuereth> you get that wierd <unknown> bit *because* you need to specify a few flags to the build for making releases
13:03 < jsuereth> SO, while you have something that works, it could be subtly different from what I release. I'm always hesitant to endorse such things
13:04 < jsuereth> pdxleif: Ah, that's fine then
13:04 < jsuereth> pdxleif: If you use it just for REPL
13:04 < WooLooWoo> which do you build?
13:04 < jsuereth> pdxleif: My guess is that symlink is the cause of your woes
13:04 < jsuereth> just a random guess
13:04 < jsuereth> WooLooWoo: me?
13:05 < pdxleif> I could hack on that package and see about having it use the pre-built version, submit it, or maybe file an issue on it or something.
13:05 < pdxleif> But most serious work happens in SBT, and not the OS package, anyways.
13:05 < WooLooWoo> sorry, yes, you said the scala-lang tgz isn't tested
13:06 < jsuereth> WooLooWoo: No, it is tested
13:06 < jsuereth> WooLooWoo: We test it under certain build flags though
13:07 < jsuereth> WooLooWoo: If you want your binaries to be equivalent (i.e. all metadata the same), you want: ant dist-opt -Dbuild.release=true (at the minimum)
13:07 < pdxleif> Says that arch package is maintained by Sergej Pupykin...
13:07 < jsuereth> you also want to be using the same JDK we are
13:07 < WooLooWoo> jsuereth: which JDK?
13:08 < jsuereth> pdxleif: I went to a lot of work to ensure the pre-built package is good enough for distros. I actually have my own re-packaging for deb/rpm here: https://github.com/scala/scala-dist/tree/master/installer
13:08 < jsuereth> WooLooWoo: For the 2.9.x series - OpenJDK 6
13:08 < jsuereth> WooLooWoo: for 2.8.x series, Sun's JDK 5