Check text_edits is null (prabirshrestha#697)

* Check text_edits is null

Some Language Server return null

* Add test for textEdit is null

* Check additionalTextEdits is null

Author: mattn

autoload/lsp/ui/vim/completion.vim

@@ -102,7 +102,7 @@ function! s:on_complete_done_after() abort
   endif
 
   " apply additionalTextEdits.
-  if has_key(l:completion_item, 'additionalTextEdits')
+  if has_key(l:completion_item, 'additionalTextEdits') && !empty(l:completion_item['additionalTextEdits'])
     let l:saved_mark = getpos("'a")
     let l:pos = getpos('.')
     call setpos("'a", l:pos)

autoload/lsp/utils/text_edit.vim

@@ -43,6 +43,10 @@ function! lsp#utils#text_edit#apply_text_edits(uri, text_edits) abort
     " ((0, 0), (0, 1), "") - remove first character 'a'
     " ((0, 4), (0, 5), "") - remove fifth character 'e'
     " ((0, 2), (0, 3), "") - remove third character 'c'
+    if empty(a:text_edits)
+        return
+    endif
+
     let l:text_edits = sort(deepcopy(a:text_edits), '<SID>sort_text_edit_desc')
     let l:i = 0
 

test/lsp/utils/text_edit.vimspec

@@ -587,6 +587,18 @@ Describe lsp#utils#text_edit
             let l:buffer_text = s:get_text()
             Assert Equals(l:buffer_text, ['package main', '', 'import java.util.ArrayList;', '', 'public class Main {}', ''])
         End
+
+        It adds null
+            let l:text = ['package main', '', 'import java.util.ArrayList;', '', 'public class Main {}']
+            call s:set_text(l:text)
+
+            call lsp#utils#text_edit#apply_text_edits(
+                \ expand('%'),
+                \ v:null)
+
+            let l:buffer_text = s:get_text()
+            Assert Equals(l:buffer_text, l:text + [''])
+        End
     End
 End