hunks: only enable coc-git extension, if explicitly enabled by the user

As requested by the coc maintainer, this is explicitly disabled, unless
the user configures vim-airline to use it for the branch extension. This
is done, because the `CocAction('extensionStats')` function is known to
be slow and this may cause a slow startup.

autoload/airline/extensions/hunks.vim

@@ -16,24 +16,14 @@ let s:non_zero_only = get(g:, 'airline#extensions#hunks#non_zero_only', 0)
 let s:hunk_symbols = get(g:, 'airline#extensions#hunks#hunk_symbols', ['+', '~', '-'])
 
 function! s:coc_git_enabled() abort
-  if !exists("*CocAction")
+  if !exists("*CocAction") ||
+     !get(g:, 'airline#extensions#hunks#coc_git', 0)
+     " coc-git extension is disabled by default
+     " unless specifically being enabled by the user
+     " (as requested from coc maintainer)
     return 0
   endif
-  if exists("s:airline_coc_git_enabled")
+  return 1
-    return s:airline_coc_git_enabled
-  endif
-  let extensions=CocAction('extensionStats')
-  if type(extensions) != type([])
-    " not yet initialized? Assume it is available...
-    return 1
-  endif
-  let coc_git=filter(extensions, 'v:val.id is# "coc-git" && v:val.state is# "activated"')
-  if !empty(coc_git)
-    let s:airline_coc_git_enabled = 1
-  else
-    let s:airline_coc_git_enabled = 0
-  endif
-  return s:airline_coc_git_enabled
 endfunction
 
 function! s:get_hunks_signify() abort

doc/airline.txt

@@ -758,6 +758,11 @@ querying how many changes you got. It will return something like '+4 ~2 -1'.
 <
 * set hunk count symbols. >
   let g:airline#extensions#hunks#hunk_symbols = ['+', '~', '-']
+
+* enable coc-git extension.
+  If not set to 1, vim-airline will not consider to use coc-git for the hunks
+  extension. Make sure to have the coc-git extension enabled. >
+  let g:airline#extensions#hunks#coc_git = 1
 <
 -------------------------------------                     *airline-keymap*
 vim-keymap