[PATCH] Fix notmuch-describe-key

[Sheng Yang]

For the second case, I mean the call of notmuch-help fails with the
following error:

notmuch-documentation-first-line: Symbol’s function definition is void: aya-persist-snippet

Sorry for the confusion. Other void functions include the following for me

spacemacs/search-pt-grep-region-or-symbol
spacemacs/search-pt-grep
spacemacs/search-rg-grep-region-or-symbol
spacemacs/search-rg-grep
spacemacs/search-ack-grep-region-or-symbol
spacemacs/search-ack-grep


I think either is fine: notmuch-documentation-first-line is only called
from notmuch-describe-key, we can do it in either function. The
advantage of fixing it in notmuch-describe-key is that we can avoid some
lines that have key bindings without description.

Here are some known problems that are not fixed by this patch:
1. For me, 600+ lines of help are produced by notmuch-hello, which is a
lot. (Maybe not as much, as counsel-desbinds tells me there are 3000+
key bindings)
2. Key bindings using leader key (in spacemacs, it is ESC) are not
shown correctly: instead of showing "SPC q q", notmuch-help shows "q q"
for a key binding <SPC q q>. 
3. Some lines show key bindings with no explanation. Possibly because no
doc string is available for these functions.

If we do not need to stick to the current implementation of
notmuch-help, a simple way is to port counsel-desbinds or
counsel--desbinds-cands from counsel.el.


Matt Armstrong <marmstrong at google.com> writes:

> Can you describe case 2 in more detail?  I am wondering what "crash the
> whole process means" -- Emacs itself crashes?  If so, is there an Emacs
> bug filed for it?  Also, perhaps the bug should be worked around with in
> notmuch-documentation-first-line itself, rather than its caller?
>
>  

-- 
Sheng Yang(杨圣), PhD student
Computer Science Department
University of Maryland, College Park
E-mail: yangsheng6810 at gmail.com