Support fern#util#expand()

Author: lambdalisue

plugin/fern_hijack.vim

@@ -3,21 +3,29 @@ if exists('g:loaded_fern_hijack') || ( !has('nvim') && v:version < 801 )
 endif
 let g:loaded_fern_hijack = 1
 
-function! s:suppress_netrw() abort
-  if exists('#FileExplorer')
-    autocmd! FileExplorer *
-  endif
-endfunction
-
 function! s:hijack_directory() abort
-  let path = expand('%:p')
+  let path = s:expand('%:p')
   if !isdirectory(path)
     return
   endif
   silent bwipeout %
   execute printf('Fern %s', fnameescape(path))
 endfunction
 
+function! s:suppress_netrw() abort
+  if exists('#FileExplorer')
+    autocmd! FileExplorer *
+  endif
+endfunction
+
+function! s:expand(expr) abort
+  try
+    return fern#util#expand(a:expr)
+  catch /^Vim\%((\a\+)\)\=:E117:/
+    return expand(a:expr)
+  endtry
+endfunction
+
 augroup fern-hijack
   autocmd!
   autocmd VimEnter * call s:suppress_netrw()