WUI can make an <a href> tag with no contents

[drewp]

I put a file by doing this:

bang(pts/4):~/allmydata-tahoe-0.9.0% bin/tahoe put -u ​http://10.1.0.1:8123 -d /unsafe/tahoe/pycon /etc/abcde.conf /etc/abcde.conf

and now this directory view: ​http://127.0.0.1:8123/uri/URI%3ADIR2%3Agb4kveh2zsq4bprwzx3p7vbtq4%3Avd6taniw7nvime4s4ylx3az4mavhgvy5kxmxbtubvytjrcckltia/

contains this invisible link: <td><a href="/uri/URI%3ADIR2%3A3lciitsbt7nho6hyxwq3rve6eq%3Axei7hfd5i42u66g7owwea2md5hhp3bc7jble2tkd476qrc6uhnpa"/></td>

I wish that dir would have a label like "[root]" or something.

(This is on the test grid at pb://bybv6lpnj6doxxa3mtupofooreqv6tpb@207.7.131.41:40264,127.0.0.1:40264/introducer)

[warner]

FYI, this is still a problem. The 'tahoe put' command created a path of (, 'etc', 'abcde.conf'), rooted in the default "tahoe:" alias. The webapi PUT url that gets used is http://NODE/uri/DIRCAP//etc/abcde.conf (note the double-slash).

We've discouraged empty strings as pathname components in lots of other places. Maybe it's time to forbid them in the PUT command. We need to leave the POST?t=delete&name="" command so you can clean up from this sort of thing.

Incidentally, the correct command would be "tahoe put /etc/abcde.conf etc/abcde.conf", which would treat the default "tahoe:" alias as a root directory. So maybe the other fix is to disallow leading slashes after the (possibly implied) alias.

[warner]

Oops, didn't preview first and broke the wiki formatting. I meant to say that it created a path of ('', 'etc', 'abcde.conf').

[warner]

Fixed, in 499add09e6b1ba62, with two changes. The first is an internal webapi fix that disallows empty strings as pathname components when traversing directories. The second is a change to the "tahoe put" command that notices when you're trying to do that and tells you to try it without the leading slash instead.

This shouldn't affect the WUI's ability to delete or rename a directory with an empty name (to fix this sort of breakage).