Julia: `realpath` strips trailing slash on linux but not on windows.

[oxinabox]

realpath works different on linux and windows.

For '..../somedir being a real path to a directory
on linux realpath(".../somedir/") =="..../somedir",
on windows realpath(".../somedir/") =="..../somedir/"

realpath should be useful for making paths more consistent in their behavior, not less.

The linux behavour matches that of the realpath command,
the windows behavior is what I would have expected to happen (but that is just me)

I guess this is a LibUV bug, maybe someone can test and upstream it?

[StefanKarpinski]

One of the reasons to call realpath is to get a "canonical name" for a file, so it's not desirable for the result to depend on input details like whether there was or was not a trailing slash given in the input name. For files a trailing slash should probably lead to failure, for directories, we should either always return a result with or without a trailing slash, regardless of what the input had. It's kind of nice that a file and a directory with the same path have different canonical names, so maybe that's the better behavior. On the other hand, maybe it's weird for the canonical name for a directory to end in a slash.

[stevengj]

Note that realpath has changed recently on Windows (#30611), and the new implementation should not have this problem I'm guessing. Are trailing slashes still an issue on master?