This commit makes watch event logging work in the '~' command. The
previous design of the command made this difficult, so there is a
significant re-design of the implementation of '~'. I believe that this
redesign will allow the feature to be maintained and improved more
easily moving forward. With the redesign, it is now possible to test the
business logic of the watch command (and I add a rudimentary test that I
will build upon in subsequent commits).
A bonus of this redesign is that now if the user tries to watch an
invalid command, the watch will immediately terminate with an error
rather than get stuck waiting for events when the task can never
possibly succeed.
The previous implementation of the '~' command makes it difficult
to dynamically control the implementation arguments because it is
implemented in the command project which makes it unable to depend on
any task keys that are defined in the build. It works around this by
putting all of it's configuration in the Watched attribute which is
stored globally. This would not have been necessary if the function had
been defined in the main project where it could just extract the value
of the watched task rather than relying on the global attribute value.
Moreover, because it cannot depend on tasks, it makes it nigh impossible
to use the logging framework within the '~' command.
Another issue with the previous implementation is that it's somewhat
difficult to reason about. The executeContinuously has effectively two
entry points: one for the first time the command is run and one for each
subsequent invocation when a new build is triggered. The successive
invocations are triggered by prepending commands to run to the previous
state. This is made recursive by prepending the initial command (that
was prefixed with '~'. Which branch we're in is determined by checking
for the existence of a temporary attribute, that we must ensure that we
remove when the build is stopped. This makes a lot of behavior non-local and
difficult for an outsider who is less familiar with sbt to understand.
Broadly, this refactor does two things:
1) Move the definition of continuous from BasicCommands to BuiltInCommands
2) Re-work the implementation to be executed in code rather than using
the sbt dsl.
The first part is simple. We just add an implementation of continuous to
BuiltInCommands and remove it from the list of BasicCommands. We need to
leave in the legacy implementation for binary compatibility. I also
moved all of the actual implementation logic into Watched, which makes
maintenance easier since most of the logic is in one place.
The second part is more complicated. Rather than rely on the sbt dsl
(e.g. `(ClearOnFailure :: next :: FailureWall :: repeat :: s)`) to
parse and run the command. We manually parse the command and generate a
task of type `() => State`. We don't actually need to do anything with
the generated state because we're going to return the original state at
the end of the command no matter what. With this task, we can then
create a tail recursive function that repeatedly executes the task until
the watch is terminated.
The parsing is handled in the Watch.command method (which is where I
moved the refactored BasicCommands.continuous implementation). The
actual task running and monitoring is handled in Watched.watch. This
method has no reference to the sbt state, which makes it testable. It sets
up an event monitor and then delegates the recursive monitoring to a
small nested function, Watched.watch.impl. One nice thing about this
approach is that it is very easy to reason about the life cycle of the
EventMonitor. The recursive call is within a try { } finally { } where
the monitor and stdin are guaranteed to be cleared at the end.
Adding support for a custom (and default) watch logger is trivial with
the new infrastructure and is done via the watchLogger TaskKey.
There was a small reporting race condition that was introduced by the
change to (2). Because the new implementation is able to bypass command
parsing for triggered builds, the watch message would usually end up
being printed before the task outcome was fully logged. To work around
this, I made the watch and triggered messages be logged rather than
printed directly to stdout. As a result, the only user visible result of
this change should be that instead of seeing:
"1. Waiting for source changes in project foo... (press enter to interrupt)",
users will now see:
"[info] 1. Waiting for source changes in project foo... (press enter to interrupt)".
The State file in intellij was littered with red squiggly lines wherever
the extension methods of State called a different extension method of
State. These went away when I switched to an implicit class, which is
the preferred way of adding extension methods since scala 2.10. As a
bonus, I was able to switch the implicit class to be a value class, so
it should not actually make a new object in most use cases.
I had to re-implement the stateOps method to delegate to the implicit
class for binary compatibility.
Fixes https://github.com/sbt/sbt/issues/3508
This forks an instance of sbt in the background when it's not running already.
```
$ time sbt -client compile
Getting org.scala-sbt sbt 1.2.0-SNAPSHOT (this may take some time)...
:: retrieving :: org.scala-sbt#boot-app
confs: [default]
79 artifacts copied, 0 already retrieved (28214kB/130ms)
[info] entering *experimental* thin client - BEEP WHIRR
[info] server was not detected. starting an instance
[info] waiting for the server...
[info] waiting for the server...
[info] server found
> compile
[success] completed
sbt -client compile 9.25s user 2.39s system 33% cpu 34.893 total
$ time sbt -client compile
[info] entering *experimental* thin client - BEEP WHIRR
> compile
[success] completed
sbt -client compile 3.55s user 1.68s system 107% cpu 4.889 total
```
Fixes https://github.com/sbt/sbt/issues/1502
This adds `--addPluginSbtFile=<file>` command, which adds the given .sbt file to the plugin build.
Using this mechanism editors or IDEs can start a build with required plugin.
```
$ cat /tmp/extra.sbt
addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.14.7")
$ sbt --addPluginSbtFile=/tmp/extra.sbt
...
sbt:helloworld> plugins
In file:/xxxx/hellotest/
...
sbtassembly.AssemblyPlugin: enabled in root
```
A thread blocking on System.in.read() cannot be interrupted, so check
System.in.available before blocking. This is how it used to work. It
requires https://github.com/sbt/io/pull/149 or else a cpu will be
pegged by the EventMonitor user input thread spinning on
System.in.available.
In https://github.com/sbt/io/pull/142, I add a new api for watching for
source file events. This commit updates sbt to use the new EventMonitor
based api. The EventMonitor has an anti-entropy parameter, so that
multiple events on the same file in a short window of time do not
trigger a build. I add a key to tune it.
The implementation of executeContinuously is pretty similar. The main
changes are that shouldTerminate now blocks (EventMonitor spins up a
thread to check the termination condition) and that the
EventMonitor.watch method only returns a Boolean. This is because
the event monitor contains mutable state. It does, however, have a
state() method that returns an immutable snapshot of the state.
I noticed that my custom WatchService was never cleaned up by sbt and
realized that after every build we were making a new WatchService. At
the same time, we were reusing the WatchState from the previous run,
which was using the original WatchService. This was particularly
problematic because it prevented us from registering any paths with the
new watch service. This may have prevented some of the file updates
from being seen by the watch service. Moreover, because we lost the
reference to the original WatchService, there was no way to clean it up,
which was a resource leak.
May be related to #3775, #3695
* 1.1.x:
Update mimaPreviousArtifacts/sbt.version
Introduce SBT_GLOBAL_SERVER_DIR env var to override too long paths
Handle very long socket file paths on UNIX
Conflicts:
project/build.properties
Ethan Atkins
eugene yokota
Jason Pickens
Holden Karau
Dale Wijnand
Jason Zaugg
Steve Waldman