Allow the completer (omnifunc or server) to reset the start column

autoload/youcompleteme.vim

@@ -411,6 +411,8 @@ function! s:SetUpCompleteopt()
   " don't need to insert the prefix; they just type the differentiating chars.
   " Also, having this option set breaks the plugin.
   set completeopt-=longest
+  set completeopt+=noselect
+  set completeopt+=noinsert
 
   if g:ycm_add_preview_to_completeopt
     set completeopt+=preview
@@ -705,13 +707,11 @@ function! s:InvokeCompletion()
   endif
 
   " <c-x><c-u> invokes the user's completion function (which we have set to
-  " youcompleteme#Complete), and <c-p> tells Vim to select the previous
-  " completion candidate. This is necessary because by default, Vim selects the
-  " first candidate when completion is invoked, and selecting a candidate
-  " automatically replaces the current text with it. Calling <c-p> forces Vim to
-  " deselect the first candidate and in turn preserve the user's current text
-  " until he explicitly chooses to replace it with a completion.
-  call feedkeys( "\<C-X>\<C-U>\<C-P>", 'n' )
+  " youcompleteme#Complete). Note that when we enabled YCM, we added 'noinsert'
+  " and 'noselect' to 'completeopt'. This prevents Vim from selecting or
+  " inserting the first match (and allows us to use complete_check() within the
+  " 'findstart' call).
+  call feedkeys( "\<C-X>\<C-U>", 'n' )
 endfunction
 
 
@@ -744,7 +744,7 @@ function! youcompleteme#Complete( findstart, base )
       return -2
     endif
     exec s:python_command "ycm_state.CreateCompletionRequest()"
-    return s:Pyeval( 'base.CompletionStartColumn()' )
+    return s:Pyeval( 'ycm_state.GetCompletionStartColumn()' )
   else
     return s:GetCompletions()
   endif
@@ -759,7 +759,7 @@ function! youcompleteme#OmniComplete( findstart, base )
     let s:omnifunc_mode = 1
     exec s:python_command "ycm_state.CreateCompletionRequest(" .
           \ "force_semantic = True )"
-    return s:Pyeval( 'base.CompletionStartColumn()' )
+    return s:Pyeval( 'ycm_state.GetCompletionStartColumn()' )
   else
     return s:GetCompletions()
   endif

python/ycm/client/completion_request.py

@@ -59,12 +59,13 @@ def RawResponse( self ):
         with HandleServerException( truncate = True ):
           raise MakeServerException( e )
 
-      return response[ 'completions' ]
+      return response
     return []
 
 
   def Response( self ):
-    return _ConvertCompletionDatasToVimDatas( self.RawResponse() )
+    return _ConvertCompletionDatasToVimDatas(
+      self.RawResponse()[ 'completions' ])
 
 
 def ConvertCompletionDataToVimData( completion_data ):

python/ycm/client/omni_completion_request.py

@@ -30,6 +30,7 @@ class OmniCompletionRequest( CompletionRequest ):
   def __init__( self, omni_completer, request_data ):
     super( OmniCompletionRequest, self ).__init__( request_data )
     self._omni_completer = omni_completer
+    self._results = None
 
 
   def Start( self ):
@@ -41,7 +42,11 @@ def Done( self ):
 
 
   def RawResponse( self ):
-    return _ConvertVimDatasToCompletionDatas( self._results )
+    return {
+      'completions': _ConvertVimDatasToCompletionDatas( self._results ) ,
+      'completion_start_column': self.request_data[ 'start_column' ],
+      'errors': []
+    }
 
 
   def Response( self ):

python/ycm/omni_completer.py

@@ -89,6 +89,12 @@ def ComputeCandidatesInner( self, request_data ):
 
       items = vim.eval( ''.join( omnifunc_call ) )
 
+      # Use the start column calculated by the omnifunc, rather than our own
+      # interpretation. This is important for certain languages where our
+      # identifier detection is either incorrect or not compatible with the
+      # behaviour of the omnifunc.
+      request_data.SetCompletionStartColumn( return_value + 1 )
+
       if isinstance( items, dict ) and 'words' in items:
         items = items[ 'words' ]
 

python/ycm/youcompleteme.py

@@ -271,6 +271,7 @@ def CreateCompletionRequest( self, force_semantic = False ):
       if self._omnicomp.ShouldUseNow( wrapped_request_data ):
         self._latest_completion_request = OmniCompletionRequest(
             self._omnicomp, wrapped_request_data )
+        self._latest_completion_request.Start()
         return self._latest_completion_request
 
     request_data[ 'working_dir' ] = utils.GetCurrentDirectory()
@@ -279,12 +280,21 @@ def CreateCompletionRequest( self, force_semantic = False ):
     if force_semantic:
       request_data[ 'force_semantic' ] = True
     self._latest_completion_request = CompletionRequest( request_data )
+    self._latest_completion_request.Start()
     return self._latest_completion_request
 
 
+  def GetCompletionStartColumn( self ):
+    request = self.GetCurrentCompletionRequest()
+    while not request.Done():
+      if vimsupport.GetBoolValue( 'complete_check()' ):
+        return base.CompletionStartColumn()
+
+    return request.RawResponse()[ 'completion_start_column' ] - 1
+
+
   def GetCompletions( self ):
     request = self.GetCurrentCompletionRequest()
-    request.Start()
     while not request.Done():
       try:
         if vimsupport.GetBoolValue( 'complete_check()' ):