Improve checking for 'completionProvider' (#1574)

Author: Jorenar

autoload/lsp/capabilities.vim

@@ -189,6 +189,10 @@ function! lsp#capabilities#get_code_action_kinds(server_name) abort
     return []
 endfunction
 
+function! lsp#capabilities#has_completion_provider(server_name) abort
+    return s:has_provider(a:server_name, 'completionProvider')
+endfunction
+
 function! lsp#capabilities#has_completion_resolve_provider(server_name) abort
     return s:has_provider(a:server_name, 'completionProvider', 'resolveProvider')
 endfunction

autoload/lsp/omni.vim

@@ -204,8 +204,7 @@ endfunction
 function! s:find_complete_servers() abort
     let l:server_names = []
     for l:server_name in lsp#get_allowed_servers()
-        let l:init_capabilities = lsp#get_server_capabilities(l:server_name)
-        if has_key(l:init_capabilities, 'completionProvider')
+        if lsp#capabilities#has_completion_provider(l:server_name)
             " TODO: support triggerCharacters
             call add(l:server_names, l:server_name)
         endif

autoload/lsp/ui/vim/completion.vim

@@ -197,11 +197,7 @@ function! s:resolve_completion_item(completion_item, server_name) abort
   endif
 
   " check server capabilities.
-  let l:capabilities = lsp#get_server_capabilities(a:server_name)
-  if !has_key(l:capabilities, 'completionProvider')
-        \ || type(l:capabilities['completionProvider']) != v:t_dict
-        \ || !has_key(l:capabilities['completionProvider'], 'resolveProvider')
-        \ || !l:capabilities['completionProvider']['resolveProvider']
+  if !lsp#capabilities#has_completion_resolve_provider(a:server_name)
     return a:completion_item
   endif