From b4beed49399808930aa94ac761bb712eeddc7e82 Mon Sep 17 00:00:00 2001
From: Andrea Cedraro <a.cedraro@gmail.com>
Date: Fri, 13 Nov 2015 14:26:04 +0100
Subject: [PATCH 1/2] Defer setting the omnifunc only the first time

Fix #1769
---
 autoload/youcompleteme.vim | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/autoload/youcompleteme.vim b/autoload/youcompleteme.vim
index 8836b275..7e4c8488 100644
--- a/autoload/youcompleteme.vim
+++ b/autoload/youcompleteme.vim
@@ -22,6 +22,7 @@ set cpo&vim
 " This needs to be called outside of a function
 let s:script_folder_path = escape( expand( '<sfile>:p:h' ), '\' )
 let s:omnifunc_mode = 0
+let s:defer_omnifunc = 1
 
 let s:old_cursor_position = []
 let s:cursor_moved = 0
@@ -88,6 +89,15 @@ function! youcompleteme#Enable()
     autocmd CompleteDone * call s:OnCompleteDone()
   augroup END
 
+  if s:defer_omnifunc
+    augroup ycm_defer_omnifunc
+      autocmd!
+      autocmd InsertEnter * call s:SetOmnicompleteFunc()
+                        \ | let s:defer_omnifunc = 0
+                        \ | autocmd! ycm_defer_omnifunc
+    augroup END
+  endif
+
   " Calling these once solves the problem of BufReadPre/BufRead/BufEnter not
   " triggering for the first loaded file. This should be the last commands
   " executed in this function!
@@ -412,6 +422,11 @@ function! s:OnBufferVisit()
 
   call s:SetUpCompleteopt()
   call s:SetCompleteFunc()
+
+  if !s:defer_omnifunc
+    call s:SetOmnicompleteFunc()
+  endif
+
   py ycm_state.OnBufferVisit()
   call s:OnFileReadyToParse()
 endfunction
@@ -544,11 +559,6 @@ function! s:OnInsertEnter()
     return
   endif
 
-  if !get( b:, 'ycm_omnicomplete', 0 )
-    let b:ycm_omnicomplete = 1
-    call s:SetOmnicompleteFunc()
-  endif
-
   let s:old_cursor_position = []
 endfunction
 

From ad4091635ea22b1a08aa8281a1e6c5a6538482b2 Mon Sep 17 00:00:00 2001
From: Andrea Cedraro <a.cedraro@gmail.com>
Date: Thu, 31 Dec 2015 00:12:38 +0100
Subject: [PATCH 2/2] Add comment expaning why we defer setting the omnifunc

---
 autoload/youcompleteme.vim | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/autoload/youcompleteme.vim b/autoload/youcompleteme.vim
index 7e4c8488..20902939 100644
--- a/autoload/youcompleteme.vim
+++ b/autoload/youcompleteme.vim
@@ -89,6 +89,12 @@ function! youcompleteme#Enable()
     autocmd CompleteDone * call s:OnCompleteDone()
   augroup END
 
+  " Setting the omnifunc require us to ask the server if it has a Native
+  " Semantic Completer for the current buffer's filetype. When vim first start
+  " this mean that we have to wait for the server to be up and running which
+  " would block vim's GUI. To avoid this we defer setting the omnifunc the
+  " first time to when we enter Insert mode and then update it on every
+  " BufferVisit as normal.
   if s:defer_omnifunc
     augroup ycm_defer_omnifunc
       autocmd!