filemanager shows broken symlinks

[steverweber]

notebook/notebook/services/contents/filemanager.py

Line 311 in ae011a1

st = os.lstat(os_path)

is using: os.lstat
Equivalent to stat(path, follow_symlinks=False).

the comment following that block of code says:
# skip over broken symlinks in listing

perhaps in the past the comment was true... however as it is now the file listing shows broken links.
The broken links are an issue for our university because we have symlinks to extra home dirs
that wont resolve... when users click them they get a 404 error page

can this be changed to use os.stat so broken symlinks are hidden, or could a config option be added to hide broken symlinks... or perhaps color code them red.

thanks

[scanon]

We are seeing this issue on our deployments and it is causing pretty serious usability problems especially with the labs interface. If a user navigates up the tree from their home directory they can quickly get to a point where they can't navigate back. I will submit a PR based on Steve's change which seems to work.