Problem
-------
Starting Scala 2.13.12, Scala 2 has in-sourced the compiler bridge
implementtion, which hopefully will be kept up to date more than the
ones in Zinc.
Solution
--------
This switches to using the pre-compiled compiler bridge for >=2.13.12.
Contrary to Scala 2, Scala 3 compiler bridges are tied to the compiler
version. There is one compiler bridge foreach compiler version.
Scala compiler bridges are pure java so they are binary compatible with
all Scala version. Consequently, we can fetch the binary module directly
without using the ZincCompilerBridgeProvider.
This commit makes it so that the scalaVersion, sbtVersion and classpath
are always passed in as parameters to any method that creates an sbt
server -- either for scripted or for the sbt server tests. By making
that change, I was able to change the implementation of scripted in the
sbt project to use publishLocalBin instead of publishLocal. This makes
the scripted tests start much faster (doc alone can easily take 30
second) with messing with the build to exclude slow tasks from
publishLocal.
As part of this change, I removed the test dependency on scriptedSbtRedux for
sbtProj and instead had scriptedSbtRedux depend on sbtProj. This allowed
me to remove some messy LocalProject logic in the resourceGenerators for
scriptedSbtReduxProj. I also had to remove a number of imports in the
scriptedSbtReduxProj because the definitions available in the sbt
package object became available.
I also removed the dependency on sbt-buildinfo and instead pass the
values from the build into test classes using scalatest properties. I
ran into a number of minor issues with the build info plugin, namely
that I couldn't get fullClasspathAsJars to reliably run as a BuildInfo
key. It also is somewhat more clear to me to just rely on the built in
scalatest functionality. The big drawback is that the scalatest
properties can only be strings, but that restriction isn't really a
problem here (strangely the TestData structure has a field configMap
which is effectively Map[String, Any] but Any is actually always String
given how the TestData is created as part of framework initialization.
Since scripted no longer publishes, scriptedUnpublished is now
effectively an alias for scripted.
To get publishLocalBin working, I had to copy private code from
IvyXml.scala into PublishBinPlugin. Once we publish a new version of
sbt, we can remove the copied code and invoke IvyXml.makeIvyXmlBefore
directly.
To demonstrate [-Yno-lub](http://eed3si9n.com/stricter-scala-with-ynolub), this shows the code changes that removes lubing (Not all subprojects are done).
After I made the changes, I switched the Scala back to normal 2.12.10.
This commit adds a new ClassLoaderCache that builds on the
ClassLoaderCache that is present in zinc (and can be used to build an
instance of the zinc ClassLoaderCache to preserve compatibility). It
differs from the zinc classloader cache that it does not use direct
SoftReferences to classloaders. Instead, we create a wrapper loader
that can't load any classes and just delegates to its parent. This
allows us to add a thread that reaps the soft reference to the wrapper
loader. Crucially, we add a custom SoftReference class that has a strong
reference to the underlying classloader. This allows us to call close on
the strong reference.
The one issue with this approach is that we can't
rescue the jvm from crashing with an OOM: metaspace because the jvm
doesn't give us a chance to close and dereference the underlying
classloaders before it crashes. It WILL collect classloaders under
normal memory pressure, just not metaspace pressure. To fix this, I
check if the MaxMetaspaceSize is set via an MxBean and, if it is, we
fill the cache with regular soft references. We are going to change the
bash script to not set -XX:MaxMetaspaceSize by default so most builds
should probably end up correctly closing the classloaders after this
change. But we should break existing builds that set MaxMetaspaceSize
but don't crash.
As part of this commit, I audited all of the places where we were
instantiating ClassLoaderCache instances and instead pass in the
state's ClassLoaderCache instance. This reduces the total number of
classloaders created.
The ZincComponentCompilerSpec was fail with a metaspace related error
when run locally with a recent version of sbt on my machine. I was able
to stop these failures by closing the URLClassLoader instances used to
compile the bridge.
Eugene Yokota
Josh Soref
xuwei-k
friendseeker
Adrien Piquerez
Lukas Rytz
Julien Richard-Foy
Ethan Atkins
Ethan Atkins
Dale Wijnand