This commit refactors things so that the nio apis are located primarily
in the nio package. Because the nio keys are a first class sbt feature,
I had to add import sbt.nio._ and sbt.nio.Keys._ to the autoimports in
BuildUtil.scala
I had some ideas for allowing the user to get a copy of system in during
a continuous build but I can't really see a good use case now so I'm
going to remove it before 1.3.0.
In my recent changes to watch, I have been moving towards a world in
which sbt manages the file inputs and outputs at the task level. The
main idea is that we want to enable a user to specify the inputs and
outputs of a task and have sbt able to track those inputs across
multiple task evaluations. Sbt should be able to automatically trigger a
build when the inputs change and it also should be able to avoid task
evaluation if non of the inputs have changed.
The former case of having sbt automatically watch the file inputs of a
task has been present since watch was refactored. In this commit, I
make it possible for the user to retrieve the lists of new, modified and
deleted files. The user can then avoid task evaluation if none of the
inputs have changed.
To implement this, I inject a number of new settings during project
load if the fileInputs setting is defined for a task. The injected
settings are:
allPathsAndAttributes -- this retrieves all of the paths described by
the fileInputs for the task along with their attributes
fileStamps -- this retrieves all of the file stamps for the files
returned by allPathsAndAttributes
Using these two injected tasks, I also inject a number of derived tasks,
such as allFiles, which returns all of the regular files returned by
allPathsAndAttributes and changedFiles, which returns all of the regular
files that have been modified since the last run.
Using these injected settings, the user is able to write tasks that
avoid evaluation if the inputs haven't changed.
foo / fileInputs += baseDirectory.value.toGlob / ** / "*.scala"
foo := {
foo.previous match {
case Some(p) if (foo / changedFiles).value.isEmpty => p
case _ => fooImpl((foo / allFiles).value
}
}
To make this whole mechanism work, I add a private task key:
val fileAttributeMap = taskKey[java.util.HashMap[Path, Stamp]]("...")
This keeps track of the stamps for all of the files that are managed by
sbt. The fileStamps task will first look for the stamp in the attribute
map and, only if it is not present, it will update the cache. This
allows us to ensure that a given file will only be stamped once per task
evaluation run no matter how the file inputs are specified. Moreover, in
a continuous build, I'm able to reuse the attribute map which can
significantly reduce latency because the default file stamping
implementation used by zinc is fairly expensive (it can take anywhere
between 300-1500ms to stamp 5000 8kb source files on my mac).
I also renamed some of the watch related keys to be a bit more clear.
This trait may not even survive until 1.4.0. It should definitely not be
public. I got a little overexcited about programming with higher kinded
types when I added it.
The newest version of io repackages a number of classes into the
sbt.nio.* packages. It also changes some of the semantics of glob
related apis. This commit updates all of the usages of the updated apis
within sbt but should have no functional difference.
Since the new watch implementation has yet to be widely deployed, we
should hold off on deprecating the old keys. They could still be
deprecated in a patch release or in 1.4.0.
I noticed in a heap dump of sbt that there were many classloaders for
the scala instance. I then realized that we were making a new
classloader for the scala library on every test run. Even worse, the
ScalaInstanceLoader instance was never closed which lead to a metaspace
leak. I moved the scala instance classloader to the global classloader
cache. Not only will these be correctly cached, they will be closed if
evicted from the cache.
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.
This adds dependency to LM implemented using Coursier.
I had to copy paste a bunch of code from sbt-coursier-shared to break the dependency to sbt.
`Global / useCoursier := false` or `-Dsbt.coursier=false` be used to opt-out of using Coursier for the dependency resolution.
I discovered that it wasn't possible to call .previous in an input task.
While I understand why you can't call .previous on an InputKey, I think
it makes sense to allow calling .previous on a TaskKey within an input
task.
Ethan Atkins
eugene yokota
Dale Wijnand
Dale Wijnand