Auto merge of #3117 - micbou:omnifunc-restore-cursor-position, r=micbou

[READY] Restore cursor position after omnifunc calls

An omnifunc may move the cursor position even on the first call, e.g. [`completeR` from the `Nvim-R` plugin](https://github.com/jalvesaq/Nvim-R/blob/0db20893d34654aefe2ea1027d815159556330a7/R/common_global.vim#L3383). The cursor position is not restored between the two calls because it's unnecessary with the changes from PR #3112.

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/valloric/youcompleteme/3117)
<!-- Reviewable:end -->

python/ycm/omni_completer.py

@@ -78,6 +78,14 @@ class OmniCompleter( Completer ):
     if not self._omnifunc:
       return []
 
+    # Calling directly the omnifunc may move the cursor position. This is the
+    # case with the default Vim omnifunc for C-family languages
+    # (ccomplete#Complete) which calls searchdecl to find a declaration. This
+    # function is supposed to move the cursor to the found declaration but it
+    # doesn't when called through the omni completion mapping (CTRL-X CTRL-O).
+    # So, we restore the cursor position after the omnifunc calls.
+    line, column = vimsupport.CurrentLineAndColumn()
+
     try:
       start_column = vimsupport.GetIntValue( self._omnifunc + '(1,"")' )
       if start_column < 0:
@@ -92,14 +100,6 @@ class OmniCompleter( Completer ):
       # because it affects the value returned by 'query'.
       request_data[ 'start_column' ] = start_column + 1
 
-      # Calling directly the omnifunc may move the cursor position. This is the
-      # case with the default Vim omnifunc for C-family languages
-      # (ccomplete#Complete) which calls searchdecl to find a declaration. This
-      # function is supposed to move the cursor to the found declaration but it
-      # doesn't when called through the omni completion mapping (CTRL-X CTRL-O).
-      # So, we restore the cursor position after calling the omnifunc.
-      line, column = vimsupport.CurrentLineAndColumn()
-
       # Vim internally moves the cursor to the start column before calling again
       # the omnifunc. Some omnifuncs like the one defined by the
       # LanguageClient-neovim plugin depend on this behavior to compute the list
@@ -112,8 +112,6 @@ class OmniCompleter( Completer ):
                         "')" ]
       items = vim.eval( ''.join( omnifunc_call ) )
 
-      vimsupport.SetCurrentLineAndColumn( line, column )
-
       if isinstance( items, dict ) and 'words' in items:
         items = items[ 'words' ]
 
@@ -127,6 +125,9 @@ class OmniCompleter( Completer ):
         OMNIFUNC_RETURNED_BAD_VALUE + ' ' + str( error ) )
       return []
 
+    finally:
+      vimsupport.SetCurrentLineAndColumn( line, column )
+
 
   def FilterAndSortCandidatesInner( self, candidates, sort_property, query ):
     request_data = {

python/ycm/tests/omni_completer_test.py

@@ -622,9 +622,9 @@ def OmniCompleter_GetCompletions_RestoreCursorPositionAfterOmnifuncCall_test(
   # This omnifunc moves the cursor to the test definition like
   # ccomplete#Complete would.
   def Omnifunc( findstart, base ):
+    vimsupport.SetCurrentLineAndColumn( 0, 0 )
     if findstart:
       return 5
-    vimsupport.SetCurrentLineAndColumn( 0, 0 )
     return [ 'length' ]
 
   current_buffer = VimBuffer( 'buffer',