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.
The usingTerminal method synchronizes the JLine object which can lead to
deadlock if multiple threads call it. When we just to want to read the
attributes of the terminal, but not modify it, there doesn't seem to be
any reason to use a lock.
I was seeing a number of compiler warnings about the type parameter
Scope:
Settings.scala:55:12: type parameter Scope defined in trait Init shadows class Scope defined in package util. You may want to rename your type parameter, or possibly remove it.
I'm not sure why I wasn't seeing these before, but the fix is simple.
Although this is technically in the internal package, it is exposed to
users when they write a custom input task. I do not think that we should
prevent users/plugin authors from writing their own parser
implementations if there is a different library they prefer. By my
count, there are 21 implementations of this interface in sbt, so it's
unlikely that there is much benefit from a pattern matching perspective.
While the AnyLeft and AnyRight types are necessary to make the extension
class work, I don't want to leak the AnyLeft or AnyRight traits into the
public api. It wasn't neceessary to annotate `some`, but it's good
practice to annotate anything public anyway.
Make sure that we generate valid ID (according to matches(ID, s)) so
that we properly test the new validID implementation.
And that's what led to the bug fix. :)
It turned up in profiling sessions. Previously, it used parser combinators
which are somewhat slow especially when the JVM is still cold.
The grammar for ID is simple enough to afford this handwritten parser.
Fixessbt/sbt#1812
This adds unified slash syntax for both sbt shell and the build.sbt DSL.
Instead of the current `<project-id>/config:intask::key`,
this adds `<project-id>/<config-ident>/intask/key` where <config-ident> is the Scala identifier notation for the configurations like `Compile` and `Test`.
This also adds a series of implicits called `SlashSyntax` that adds `/` operators to project refererences, configuration, and keys such that the same syntax works in build.sbt.
These examples work for both from the shell and in build.sbt.
Global / cancelable
ThisBuild / scalaVersion
Test / test
root / Compile / compile / scalacOptions
ProjectRef(uri("file:/xxx/helloworld/"),"root")/Compile/scalacOptions
Zero / Zero / name
The inspect command now outputs something that can be copy-pasted:
> inspect compile
[info] Task: sbt.inc.Analysis
[info] Description:
[info] Compiles sources.
[info] Provided by:
[info] ProjectRef(uri("file:/xxx/helloworld/"),"root")/Compile/compile
[info] Defined at:
[info] (sbt.Defaults) Defaults.scala:326
[info] Dependencies:
[info] Compile/manipulateBytecode
[info] Compile/incCompileSetup
[info] Reverse dependencies:
[info] Compile/printWarnings
[info] Compile/products
[info] Compile/discoveredSbtPlugins
[info] Compile/discoveredMainClasses
[info] Delegates:
[info] Compile/compile
[info] compile
[info] ThisBuild/Compile/compile
[info] ThisBuild/compile
[info] Zero/Compile/compile
[info] Global/compile
[info] Related:
[info] Test/compile
Dale Wijnand
Ethan Atkins
Eugene Yokota
Kazuhiro Sera
xuwei-k
Jason Pickens
Johannes Rudolph
Dale Wijnand
Simon Schäfer
kczulko