make the error message more helpful in case of no 'tahoe' alias

[prmr]

root@lodge:~/.tahoe# tahoe stats
Traceback (most recent call last):
  File "/usr/bin/tahoe", line 8, in <module>
    load_entry_point('allmydata-tahoe==1.3.0', 'console_scripts', 'tahoe')()
  File "/usr/lib/python2.5/site-packages/allmydata_tahoe-1.3.0-py2.5.egg/allmydata/scripts/runner.py", line 91, in run
    rc = runner(sys.argv[1:])
  File "/usr/lib/python2.5/site-packages/allmydata_tahoe-1.3.0-py2.5.egg/allmydata/scripts/runner.py", line 78, in runner
    rc = cli.dispatch[command](so)
  File "/usr/lib/python2.5/site-packages/allmydata_tahoe-1.3.0-py2.5.egg/allmydata/scripts/cli.py", line 374, in stats
    rc = tahoe_manifest.stats(options)
  File "/usr/lib/python2.5/site-packages/allmydata_tahoe-1.3.0-py2.5.egg/allmydata/scripts/tahoe_manifest.py", line 128, in stats
    return StatsGrabber().run(options)
  File "/usr/lib/python2.5/site-packages/allmydata_tahoe-1.3.0-py2.5.egg/allmydata/scripts/slow_operation.py", line 20, in run
    rootcap, path = get_alias(options.aliases, where, DEFAULT_ALIAS)
  File "/usr/lib/python2.5/site-packages/allmydata_tahoe-1.3.0-py2.5.egg/allmydata/scripts/common.py", line 137, in get_alias
    return aliases[default], path
KeyError: 'tahoe'

Hi,

I'm getting this error on OS X 10.5.2 when trying to run any command minus start/stop and create-*. Anyone know why this might be?

Thanks!

[zooko]

Thanks for the bug report, prmr. I'm sorry that it fell by the wayside for four months -- I don't know if I ever noticed this ticket before now. I'm changing the title to reflect what I think is the issue here -- that the error message when there is no alias registered for 'tahoe' should be more helpful and explain that the tahoe stats command expects either a dircap or an alias on the command-line, or else for there to be a dircap registered under the default 'tahoe' alias in the aliases file.

I'm also marking this ticket as "easy" -- a young hacker who wants to get into Tahoe-LAFS hacking should be able to fix this ticket easily enough even if they aren't familiar with the codebase.

[davidsarah]

I'm getting a different exception (Tahoe 1.5.0 r4044 with Python 2.6 on Windows Vista), but I think it's probably the same issue:

>c:\Python26\Scripts\tahoe ls
Traceback (most recent call last):
  File "c:\Python26\Scripts\tahoe-script.py", line 8, in <module>
    load_entry_point('allmydata-tahoe==1.5.0-r4044', 'console_scripts', 'tahoe')()
  File "c:\python26\lib\site-packages\allmydata_tahoe-1.5.0_r4044-py2.6.egg\allmydata\scripts\runner.py", line 91, in run
    rc = runner(sys.argv[1:])
  File "c:\python26\lib\site-packages\allmydata_tahoe-1.5.0_r4044-py2.6.egg\allmydata\scripts\runner.py", line 47, in runner
    config.parseOptions(argv)
  File "c:\python26\lib\site-packages\twisted-8.2.0-py2.6-win32.egg\twisted\python\usage.py", line 231, in parseOptions
    self.subOptions.parseOptions(rest)
  File "c:\python26\lib\site-packages\twisted-8.2.0-py2.6-win32.egg\twisted\python\usage.py", line 241, in parseOptions
    self.postOptions()
  File "c:\python26\lib\site-packages\allmydata_tahoe-1.5.0_r4044-py2.6.egg\allmydata\scripts\cli.py", line 39, in postOptions
    node_url_file = os.path.join(self['node-directory'], "node.url")
  File "c:\python26\lib\ntpath.py", line 96, in join
    assert len(path) > 0
TypeError: object of type 'NoneType' has no len()

[davidsarah]

Duplicate of #939 (actually the other way around, but that ticket has more information).

[davidsarah]

The error in comment:2 wasn't the same issue; it was due to --node-directory not being set (on Windows there is no default node directory when the registry entry set by the allmydata.com client is not present). I'll open another ticket for that.