manually check for a .exe

[martijnhoekstra]

canExecute does not guarantee an executable file, and will find java.dll before java.exe on Windows

[martijnhoekstra]

fixes #70

[som-snytt]

Is it plainer to do val realname = if (util.Properties.isWin && !name.endsWith(".exe")) s"$name.exe" else name and find that? Add case-insensitive test, of course. I was a little clever with the dot test to avoid these platform dances.

Actually the filter should read e.name == name || isWin && e.name.looksLike(name.exe). Then assert there's at most one candidate, with a nice message, to avoid future confusion.

[martijnhoekstra]

In practice, if there is neither a name or name.exe, the guess is most likely just wrong. The theoretical platform/jdk/jre that uses the same name but a different extension probably doesn't exist, and abstracting over that hypothetical probably isn't worth the brain cycles.

replacing the whole thing with something like

(p walkFilter { e => (e.name == name || e.name == e.name.looksLike(s"${name}.exe") && e.jfile.canExecute }).map(_.path).headOption

or even just

((Path(jdkHome) / "bin") .walkFilter { e => (e.name == name || e.name == s"${name}.exe") && e.jfile.canExecute }).map(_.path).headOption
should work fine enough. It's not going to find java.woozle if that is the correct file (which it isn't). If it's looking for a file named bin (which it isn't) and jdkhome/bin is a file rather than a directory (which it also isn't) it's going to return the path of jdkhome/bin rather than None mistakenly. I'm not sure that would be a great loss.

[som-snytt]

Yes, even simpler.

[martijnhoekstra]

I'll update the PR to whichever is your preference when I'll get home tonight

[som-snytt]

Your second expr gets it done. With paranoid case insensitive.

(Path(jdkHome) / "bin").walk.find(e => e.name == name || isWin && e.name.equalsIgnoreCase(s"$name.exe")).map(_.path)

When I looked yesterday, the doc on walkFilter (there's doc) inverts the sense of filter, so I wouldn't assume anything about experimental i/o library. But walk on a regular file seems OK.

[martijnhoekstra]

I wouldn't assume anything about the doc either:

  /** Equivalent to walkFilter(_ => false).
   */
  def walk: Iterator[Path] = walkFilter(_ => true)

[som-snytt]

OK I missed that one. That's so funny.

[som-snytt]

LGTM

I left a comment but it's 6/13 of a baker's dozen.

[retronym]

FTR, CreateProcess appends .exe if no extension is provided, which is why just spawning $JAVA_HOME/bin/java works on Windows.

[som-snytt]

If only the Scala team had a Windows expert on staff.

[SethTisue]

thanks Martijn!