When using process substitution or -e, Scala CLI shouldn't create .scala-build in the current directory

[alexarchambault]

Version(s)
0.1.16

Describe the bug
Running commands such as

$ scala-cli <(echo 'println("Hello")')
$ scala-cli -e 'println("Hello")'

creates a .scala-build directory, and uses it to compile the provided input. Scala CLI should rather use a directory under the home directory for that purpose.

[Gedochao]

Btw. this is only the case if no inputs are passed alongside -e 'println("Hello") or _.
What I mean is, the following two cases should still create .scala-build as normal:

$ scala-cli -e 'println(Messages.hello)' Messages.scala
$ echo 'println(Messages.hello)' | scala-cli _.sc Messages.scala

I believe if a subset of the following consists of all the passed sources, then .scala-build indeed shouldn't be created:

• snippets (-e, --scala-snippet, --java-snippet)
• piped sources (_.scala, _.java, _.sc)
• process substitution
• remote sources (i.e. GitHub gists)

We need the .scala-build directory locally only if those are combined with actual on-disk inputs.

[Gedochao]

Scala CLI should rather use a directory under the home directory for that purpose.

Maybe a temporary directory would be better than home?

[lwronski]

Scala CLI should rather use a directory under the home directory for that purpose.

Maybe a temporary directory would be better than home?

Yes, using the tmp directory seems like a good idea, or we could use Directories.cacheDir. We should analyze which option is best.