**Problem**
test task is typed to unit.
To distinguish test from any other tasks, we want to actually type this to something.
**Solution**
Forward TestResult to the test task.
This flips the default `:=` operation to the cached task.
To opt out of the cache, use `Def.uncached(...)` or
mark the key with `@cacheLevel(include = Array.empty)`
**Problem**
`run` task has been emulated via function call inside of a sandboxed classloader,
and blocking the command processing of sbt server loop.
This poses isolation and availability issues.
**Solution**
This implements client-side run where the server creates a sandbox environment, and sends the information to the client,
and the client forks a new JVM to perform the run.
The client-side behavior has been implemented in sbtn side already.
For the details about this PR, please see the blog post https://eed3si9n.com/sbt-remote-cache/.
* Add cache basics
* Refactor Attributed to use StringAttributeMap, which is Map[StringAttributeKey, String]
* Implement disk cache
* Rename Package to Pkg
* Virtualize packageBin
* Use HashedVirtualFileRef for packageBin
* Virtualize compile task
Fixes https://github.com/sbt/sbt/issues/6558
Problem
-------
sbt uses SecurityManager feature of JDK to trap `sys.exit` call during
`run`-like tasks, since we emulate `run` and `console` as function calls.
JDK 17 deprecated SecurityManager and it's printing warnings.
Solution
--------
About 10 years go, `exit` was a convenient way of quitting both Scala
REPL and sbt shell. Scala 2.11 broke this by removing the `Predef.exit`.
We still need to worry about `run` potentially calling `sys.exit`
but that can be handled using fork feature.
In the long-run, it probably is better to be JDK 17 compatible.