$ darcs setpref --list-options | egrep '^[^-]'
test
predist
boringfile
binariesfile

So far, so good.

$ darcs setpref test --list-options | egrep '^[^-]'
test
predist
boringfile
binariesfile

Now these completions aren't very useful, as darcs would refuse setting 
2 prefs in the same run.

Compare this with the behaviour of, i.e., convert, where --list-options 
is context aware:

$ darcs convert --list-options | egrep '^[^-]'                                                                     
darcs-2
export
import
$ darcs convert darcs-2 --list-options | egrep '^[^-]'
(none)

I would say that the difference is due to the fact that convert is a 
2-level command, while setpref is a single level command that accepts an 
argument. Nevertheless, they should behave similarly for completion 
purposes. [0]

'help' is similar to 'setpref', but it should also take into account if 
the command given as argument is a 2-level one. I.e.:

$ darcs help convert --list-options | egrep '^[^-]'

should output:

darcs-2
export
import

while

$ darcs help convert darcs-2 --list-options

should only print options.


Thanks,
Gian Piero.

[0] As a side note while I'm on it: --list-options given on level 1 of a 
2-level command should probably list itself. Now it doesn't:

$ darcs optimize --list-options | fgrep -- --list-options
(none)


=== darcs version ===

2.13.0 (unknown)

darcs compiled on Mar  8 2017, at 12:39:08

Context:

[fixed a todo comment regarding email encoding
Ben Franksen <benjamin.franksen@helmholtz-berlin.de>**20170226184130
 Ignore-this: 8c9d810433046cbe6880a5a62b955adb

 What qpencode does is indeed MIME Quoted Printable encoding.
]

Weak Hash: 8557abff42624c4c34db3b9e7528a97d92805003

I have stumbled over these problems, too, since I use completion a lot
(though with zsh). No idea how to fix, yet, but may think about it.

Partial fix in patch1580.

The other issue with help seems to have already been fixed. Will
re-submit the fix with changed title.