Sometimes, if a buffer triggers many whitespace check warnings,
and the Vim window size is too small, other parts of the statusline
might become unreadable.
Therefore, if the window size is smaller than say 120 characters
and the whitespace warning > 9 chars, limit it to 10 characters
and inidicate, that there is more to come
fixes#1187 by making sure, we only call functions, that actually exist.
Should make vim-airline work with lady loaded YCM, e.g. using vim-plug:
```viml
" Code to execute when the plugin is loaded on demand
Plug 'Valloric/YouCompleteMe', { 'for': 'cpp' }
autocmd! User YouCompleteMe if !has('vim_starting') | call youcompleteme#Enable() | endif
```
Make sure, b:airline_head variable is set, also it is initially set in
this function earlier. But see #1171 for an error.
Therefore, before checking if the variable is empty, make sure it
exists.
fixes#1171
This is a little bit a hack, because by the time the separators are
added, it is not clear, if the following section is empty, therefore
we need to parse the content of the following section and eval the
expressions to find out, if this is empty
Remarks:
- catch all exceptions when eval'ing statusline
- make sure, that the seperators are highlighted
even when skipping empty regions (highlight group
names need to be adjusted)
- if a section is defined as empty, it will be removed completly from
the statusline. This means, it won't be called on the next update
and may not refresh properly (e.g. when the whitespace check
triggers, therefore, the whitesapce extension has to call an
explicit redraw whenever it is supposed to be refreshed)
"system()" called by "get_git_untracked" and "get_hg_untracked" fails
sometimes. It reports error "Can't open file /tmp/***".
The root cause is that the file path for system() contains some unordinary
character and lacks quotes.
airline#extensions#load() tries to load all extensions,
the user has specified in g:airline_extensions.
However, if e.g. bufferline is requested to be loaded, but
is not installed, it will throw an error
E117: Unknown function: airline#extensions#bufferline#init
Therefore, catch E117 and show a warning.
closes#1127
