It turns out the code in Sync.scala activiely tries to transfer
the invalid modifed time of non-existent files in the source
directory over the time of the target file, which may or may
not exist. In case it exists, the modification time is set
to January 1, 1970. This is arguably a bug in Sync, which
should be adjusted to better handle mappings with source
files that do not exist. For now, however, we preserve the
current behavior, using the deprecated copyLastModified().
In Eval there is a calculation of hashes by scanning the elements
of classpath, and getting the last modification time of each
directory. When lastModified() was in use, non-existent elements
would return 0L, but getModifiedTime() will throw an exception
instead (like getLastModifiedTime(), incidentally).
So, we catch the FileNotFoundException and return 0L now as well.
Even with `publishArtifact := false` the user is still forced to define a (dummy) resolver that's never used, e.g. `publishTo := { Some("publishMeNot" at "https://publish/me/not") }`
Otherwise the following error is thrown:
```
publish
[error] java.lang.RuntimeException: Repository for publishing is not specified.
[error] at scala.sys.package$.error(package.scala:27)
[error] at sbt.Classpaths$.$anonfun$getPublishTo$1(Defaults.scala:2436)
[error] at scala.Option.getOrElse(Option.scala:121)
[error] at sbt.Classpaths$.getPublishTo(Defaults.scala:2436)
[error] at sbt.Classpaths$.$anonfun$ivyBaseSettings$48(Defaults.scala:1917)
```
This is to avoid it initialising Log4J2 (via SLF4J), which we initialise
ourselves programmatically in LogExchange. Also there's no need to
removeAll in initialState.
Fixes#3787
Fixessbt/sbt#3804
Inside the if, it seems like bunch of variables were set to blank.
Using delayed expansion seems to fix this. This is confirmed by the newly added test.
Ref https://github.com/sbt/io/pull/96
Under RFC 8089, both u1 and u3 are legal, but many of the other platforms expect traditional u3.
This will increase the compatibility/usability of sbt server, for example to integrate with Vim.