bugfix: Show exception from path matcher correctly

[tgodzik]

Previously, we would just get a stack trace:

Exception in thread "main" java.lang.IllegalArgumentException
	at sun.nio.fs.UnixFileSystem.getPathMatcher(UnixFileSystem.java:286)
	at org.scalafmt.config.ProjectFiles$FileMatcher$Nio.<init>(ProjectFiles.scala:74)
	at org.scalafmt.config.ProjectFiles$FileMatcher$.$anonfun$nio$1(ProjectFiles.scala:70)
	at scala.collection.immutable.List.map(List.scala:250)
	at scala.collection.immutable.List.map(List.scala:79)
	at org.scalafmt.config.ProjectFiles$FileMatcher$.create(ProjectFiles.scala:69)
	at org.scalafmt.config.ProjectFiles$FileMatcher$.nio(ProjectFiles.scala:70)
	at org.scalafmt.config.ProjectFiles$FileMatcher$.apply(ProjectFiles.scala:64)
	at org.scalafmt.cli.ScalafmtCoreRunner$.$anonfun$run$2(ScalafmtCoreRunner.scala:27)
	at metaconfig.Configured$ConfiguredImplicit.fold(Configured.scala:111)
	at org.scalafmt.cli.ScalafmtCoreRunner$.run(ScalafmtCoreRunner.scala:23)
	at org.scalafmt.cli.Cli$.runWithRunner(Cli.scala:140)
	at org.scalafmt.cli.Cli$.run(Cli.scala:91)
	at org.scalafmt.cli.Cli$.mainWithOptions(Cli.scala:61)
	at org.scalafmt.cli.Cli$.main(Cli.scala:43)
	at org.scalafmt.cli.Cli.main(Cli.scala)

Reported in VirtusLab/scala-cli#2415

[tgodzik]

btw. I think using regex: filter will not work currently? use excludePathswithregex: prefix but we only use nio() on excludePaths currently.

[kitbellew]

btw. I think using regex: filter will not work currently? use excludePathswithregex: prefix but we only use nio() on excludePaths currently.

this i didn't fully understand. nio() uses FileSystem.getPathMatcher which supports glob: and regex: prefixes.

[tgodzik]

btw. I think using regex: filter will not work currently? use excludePathswithregex: prefix but we only use nio() on excludePaths currently.

this i didn't fully understand. nio() uses FileSystem.getPathMatcher which supports glob: and regex: prefixes.

Ach, ok I didn't know nio also supported regexes

[kitbellew]

lgtm, only that leftover blank line :)

[kitbellew]

what happens if we append message from the exception we caught? will it explain the reason better?

[tgodzik]

I tried and it seems empty.

[tgodzik]

Ach, actually for Regex we can add it, it's null for Nio matcher

[tgodzik]

Added reason: ... line