The uglier but backward compatible fix for #3086 is to use u3 format with three slashes. This on Windows will resolve to `file:///C:/Users/foo/.sbt/preloaded`, and on Mac and Linux `file:////root/.sbt/preloaded/`. Mac and Linux are both tolerant of extra slashes on the front:
```
> eval new File(new URL("file:////Users/foo/.sbt/preloaded/").toURI)
[info] ans: java.io.File = /Users/foo/.sbt/preloaded
```
+ Don't notify ScriptMain users by moving the logic to xMain
+ Only trigger shell if shell is a defined command
+ Use existing Shell/BootCommand strings instead of new ones
The sbt/sbt-launcher-package doesn't invoke sbt with the "shell"
command. sbt has a mechanism for handling this in its "boot" command
that adds an "iflast shell" to the commands. Handle this when displaying
the "Executing in batch mode" warning.
Fixes#3004
Notify & enable users to stay in sbt's shell on the warm JVM by hitting
[ENTER] while sbt is running.
Looks like this; first I run 'sbt about', then I hit [ENTER]:
$ sbt about
[info] !!! Executing in batch mode !!! For better performance, hit [ENTER] to remain in the sbt shell
[info] Loading global plugins from /Users/dnw/.dotfiles/.sbt/0.13/plugins
[info] Loading project definition from /s/t/project
[info] Set current project to t (in build file:/s/t/)
[info] This is sbt 0.13.14-SNAPSHOT
[info] The current project is {file:/s/t/}t 0.1.0-SNAPSHOT
[info] The current project is built against Scala 2.12.1
[info] Available Plugins: sbt.plugins.IvyPlugin, sbt.plugins.JvmPlugin, sbt.plugins.CorePlugin, sbt.plugins.JUnitXmlReportPlugin, sbt.plugins.Giter8TemplatePlugin
[info] sbt, sbt plugins, and build definitions are using Scala 2.10.6
>
>
Fixes#2987
Have sbt.version set in project/build.properties is a best practice
because it makes the build more deterministic and reproducible.
With this change sbt, after ensuring that the base directory is probably
an sbt project, writes out sbt.version in project/build.properties if it
is missing.
Fixes#754
This was already supported in the internal Scripted used by sbt but not
in the ScriptedPlugin. This is fixed by just copy-pasting the modified
parser. We will have to wait for sbt itself to be built using an sbt
with the upgraded ScriptedPlugin to be able to avoid the code duplication.