Replaced Syntastic support with YCM-native code

Currently, the only supported Syntastic features are the error signs in the
gutter. Other features will be added in the future.

autoload/youcompleteme.vim

@@ -29,7 +29,7 @@ let s:cursor_moved = 0
 let s:moved_vertically_in_insert_mode = 0
 let s:previous_num_chars_on_current_line = -1
 
-let s:forced_syntastic_checker_for = {
+let s:diagnostic_ui_filetypes = {
       \ 'cpp': 1,
       \ 'c': 1,
       \ 'objc': 1,
@@ -70,10 +70,12 @@ function! youcompleteme#Enable()
   call s:SetUpCompleteopt()
   call s:SetUpKeyMappings()
 
-  if g:ycm_register_as_syntastic_checker
-    call s:TweakSyntasticOptions()
+  if g:ycm_show_diagnostics_ui
+    call s:TurnOffSyntasticForCFamily()
   endif
 
+  call s:SetUpSigns()
+
   if g:ycm_allow_changing_updatetime
     set ut=2000
   endif
@@ -157,6 +159,41 @@ function! s:SetUpKeyMappings()
 endfunction
 
 
+function! s:SetUpSigns()
+  " We try to ensure backwards compatibility with Syntastic if the user has
+  " already defined styling for Syntastic highlight groups.
+
+  if !hlexists( 'YcmErrorSign' )
+    if hlexists( 'SyntasticErrorSign')
+      highlight link YcmErrorSign SyntasticErrorSign
+    else
+      highlight link YcmErrorSign error
+    endif
+  endif
+
+  if !hlexists( 'YcmWarningSign' )
+    if hlexists( 'SyntasticWarningSign')
+      highlight link YcmWarningSign SyntasticWarningSign
+    else
+      highlight link YcmWarningSign todo
+    endif
+  endif
+
+  if !hlexists( 'YcmErrorLine' )
+    highlight link YcmErrorLine SyntasticErrorLine
+  endif
+
+  if !hlexists( 'YcmWarningLine' )
+    highlight link YcmWarningLine SyntasticWarningLine
+  endif
+
+  exe 'sign define YcmError text=' . g:ycm_error_symbol .
+        \ ' texthl=YcmErrorSign linehl=YcmErrorLine'
+  exe 'sign define YcmWarning text=' . g:ycm_warning_symbol .
+        \ ' texthl=YcmWarningSign linehl=YcmWarningLine'
+endfunction
+
+
 function! s:SetUpBackwardsCompatibility()
   let complete_in_comments_and_strings =
         \ get( g:, 'ycm_complete_in_comments_and_strings', 0 )
@@ -173,38 +210,17 @@ function! s:SetUpBackwardsCompatibility()
 endfunction
 
 
-function! s:TweakSyntasticOptions()
-  call s:ForceCFamilyFiletypesSyntasticPassiveMode()
-  call s:ForceSyntasticCFamilyChecker()
-
-  " We set this to work around segfaults in old versions of Vim
-  " See here for details: https://github.com/scrooloose/syntastic/issues/834
-  let g:syntastic_delayed_redraws = 1
+" Needed so that YCM is used instead of Syntastic
+function! s:TurnOffSyntasticForCFamily()
+  let g:syntastic_cpp_checkers = []
+  let g:syntastic_c_checkers = []
+  let g:syntastic_objc_checkers = []
+  let g:syntastic_objcpp_checkers = []
 endfunction
 
 
-" Needed so that YCM is used as the syntastic checker
-function! s:ForceSyntasticCFamilyChecker()
-  let g:syntastic_cpp_checkers = ['ycm']
-  let g:syntastic_c_checkers = ['ycm']
-  let g:syntastic_objc_checkers = ['ycm']
-  let g:syntastic_objcpp_checkers = ['ycm']
-endfunction
-
-
-" Needed so that Syntastic doesn't call :SyntasticCheck (and thus YCM code) on
-" file save unnecessarily. We call :SyntasticCheck ourselves often enough.
-function! s:ForceCFamilyFiletypesSyntasticPassiveMode()
-  let mode_map = get( g:, 'syntastic_mode_map', {} )
-  let mode_map.passive_filetypes = get( mode_map, 'passive_filetypes', [] ) +
-        \ ['cpp', 'c', 'objc', 'objcpp']
-  let g:syntastic_mode_map = mode_map
-endfunction
-
-
-function! s:ForcedAsSyntasticCheckerForCurrentFiletype()
-  return g:ycm_register_as_syntastic_checker &&
-         \ get( s:forced_syntastic_checker_for, &filetype, 0 )
+function! s:DiagnosticUiSupportedForCurrentFiletype()
+  return get( s:diagnostic_ui_filetypes, &filetype, 0 )
 endfunction
 
 
@@ -464,18 +480,15 @@ endfunction
 
 
 function! s:UpdateDiagnosticNotifications()
-  let should_display_diagnostics =
-        \ get( g:, 'loaded_syntastic_plugin', 0 ) &&
-        \ s:ForcedAsSyntasticCheckerForCurrentFiletype() &&
+  let should_display_diagnostics = g:ycm_show_diagnostics_ui &&
+        \ s:DiagnosticUiSupportedForCurrentFiletype() &&
         \ pyeval( 'ycm_state.NativeFiletypeCompletionUsable()' )
 
   if !should_display_diagnostics
     return
   endif
 
-  if pyeval( 'ycm_state.DiagnosticsForCurrentFileReady()' )
-    SyntasticCheck
-  endif
+  py ycm_state.UpdateDiagnosticInterface()
 endfunction
 
 
@@ -639,14 +652,6 @@ endfunction
 command! YcmShowDetailedDiagnostic call s:ShowDetailedDiagnostic()
 
 
-" This is what Syntastic calls indirectly when it decides an auto-check is
-" required (currently that's on buffer save) OR when the SyntasticCheck command
-" is invoked
-function! youcompleteme#CurrentFileDiagnostics()
-  return pyeval( 'ycm_state.GetDiagnosticsFromStoredRequest()' )
-endfunction
-
-
 function! s:DebugInfo()
   echom "Printing YouCompleteMe debug information..."
   let debug_info = pyeval( 'ycm_state.DebugInfo()' )

plugin/youcompleteme.vim

@@ -71,9 +71,6 @@ let g:loaded_youcompleteme = 1
 " The only defaults that are here are the ones that are only relevant to the YCM
 " Vim client and not the server.
 
-let g:ycm_register_as_syntastic_checker =
-      \ get( g:, 'ycm_register_as_syntastic_checker', 1 )
-
 let g:ycm_allow_changing_updatetime =
       \ get( g:, 'ycm_allow_changing_updatetime', 1 )
 
@@ -116,6 +113,17 @@ let g:ycm_extra_conf_vim_data =
 let g:ycm_path_to_python_interpreter =
       \ get( g:, 'ycm_path_to_python_interpreter', '' )
 
+let g:ycm_show_diagnostics_ui =
+      \ get( g:, 'ycm_show_diagnostics_ui',
+      \ get( g:, 'ycm_register_as_syntastic_checker', 1 ) )
+
+let g:ycm_error_symbol =
+      \ get( g:, 'ycm_error_symbol',
+      \ get( g:, 'syntastic_error_symbol', '>>' ) )
+
+let g:ycm_warning_symbol =
+      \ get( g:, 'ycm_warning_symbol',
+      \ get( g:, 'syntastic_warning_symbol', '>>' ) )
 
 " On-demand loading. Let's use the autoload folder and not slow down vim's
 " startup procedure.

python/ycm/client/event_notification.py

@@ -77,7 +77,7 @@ def _ConvertDiagnosticDataToVimData( diagnostic ):
   # line/column numbers are 1 or 0 based in its various APIs. Here, it wants
   # them to be 1-based.
   return {
-    'bufnr' : vimsupport.GetBufferNumberForFilename( diagnostic[ 'filepath' ]),
+    'bufnr' : vimsupport.GetBufferNumberForFilename( diagnostic[ 'filepath' ] ),
     'lnum'  : diagnostic[ 'line_num' ] + 1,
     'col'   : diagnostic[ 'column_num' ] + 1,
     'text'  : diagnostic[ 'text' ],

python/ycm/diagnostic_interface.py

@@ -0,0 +1,55 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2013  Strahinja Val Markovic  <val@markovic.io>
+#
+# This file is part of YouCompleteMe.
+#
+# YouCompleteMe is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# YouCompleteMe is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with YouCompleteMe.  If not, see <http://www.gnu.org/licenses/>.
+
+from collections import defaultdict
+from operator import itemgetter
+from ycm import vimsupport
+
+
+class DiagnosticInterface( object ):
+  def __init__( self ):
+    self._buffer_number_to_diags = {}
+    self._next_sign_id = 1
+
+
+  def UpdateWithNewDiagnostics( self, diags ):
+    self._buffer_number_to_diags = ConvertDiagListToDict( diags )
+    for buffer_number, buffer_diags in self._buffer_number_to_diags.iteritems():
+      if not vimsupport.BufferIsVisible( buffer_number ):
+        continue
+
+      vimsupport.UnplaceAllSignsInBuffer( buffer_number )
+      for diag in buffer_diags:
+        vimsupport.PlaceSign( self._next_sign_id,
+                              diag[ 'lnum' ],
+                              buffer_number,
+                              diag[ 'type' ] == 'E' )
+        self._next_sign_id += 1
+
+
+def ConvertDiagListToDict( diags ):
+  buffer_to_diags = defaultdict( list )
+  for diag in diags:
+    buffer_to_diags[ diag[ 'bufnr' ] ].append( diag )
+  for buffer_diags in buffer_to_diags.itervalues():
+    # We also want errors to be listed before warnings so that errors aren't
+    # hidden by the warnings; Vim won't place a sign oven an existing one.
+    buffer_diags.sort( key = lambda diag: itemgetter( 'lnum', 'col', 'type' ) )
+  return buffer_to_diags
+

python/ycm/vimsupport.py

@@ -83,15 +83,22 @@ def GetUnsavedAndCurrentBufferData():
 
 
 def GetBufferNumberForFilename( filename, open_file_if_needed = True ):
-  return int( vim.eval( "bufnr('{0}', {1})".format(
+  return GetIntValue( "bufnr('{0}', {1})".format(
       os.path.realpath( filename ),
-      int( open_file_if_needed ) ) ) )
+      int( open_file_if_needed ) ) )
 
 
 def GetCurrentBufferFilepath():
   return GetBufferFilepath( vim.current.buffer )
 
 
+def BufferIsVisible( buffer_number ):
+  if buffer_number < 0:
+    return False
+  window_number = GetIntValue( "bufwinnr({0})".format( buffer_number ) )
+  return window_number != -1
+
+
 def GetBufferFilepath( buffer_object ):
   if buffer_object.name:
     return buffer_object.name
@@ -100,6 +107,18 @@ def GetBufferFilepath( buffer_object ):
   return os.path.join( os.getcwd(), str( buffer_object.number ) )
 
 
+def UnplaceAllSignsInBuffer( buffer_number ):
+  if buffer_number < 0:
+    return
+  vim.command( 'sign unplace * buffer={0}'.format( buffer_number ) )
+
+
+def PlaceSign( sign_id, line_num, buffer_num, is_error = True ):
+  sign_name = 'YcmError' if is_error else 'YcmWarning'
+  vim.command( 'sign place {0} line={1} name={2} buffer={3}'.format(
+    sign_id, line_num, sign_name, buffer_num ) )
+
+
 # Given a dict like {'a': 1}, loads it into Vim as if you ran 'let g:a = 1'
 # When |overwrite| is True, overwrites the existing value in Vim.
 def LoadDictIntoVimGlobals( new_globals, overwrite = True ):
@@ -164,6 +183,7 @@ def PostVimMessage( message ):
   vim.command( "echohl WarningMsg | echom '{0}' | echohl None"
                .format( EscapeForVim( str( message ) ) ) )
 
+
 # Unlike PostVimMesasge, this supports messages with newlines in them because it
 # uses 'echo' instead of 'echomsg'. This also means that the message will NOT
 # appear in Vim's message log.

python/ycm/youcompleteme.py

@@ -23,6 +23,7 @@ import tempfile
 import json
 from ycm import vimsupport
 from ycm import utils
+from ycm.diagnostic_interface import DiagnosticInterface
 from ycm.completers.all.omni_completer import OmniCompleter
 from ycm.completers.general import syntax_parse
 from ycm.completers.completer_utils import FiletypeCompleterExistsForFiletype
@@ -64,6 +65,7 @@ class YouCompleteMe( object ):
   def __init__( self, user_options ):
     self._user_options = user_options
     self._user_notified_about_crash = False
+    self._diag_interface = DiagnosticInterface()
     self._omnicomp = OmniCompleter( user_options )
     self._latest_completion_request = None
     self._latest_file_parse_request = None
@@ -271,6 +273,13 @@ class YouCompleteMe( object ):
     return []
 
 
+  def UpdateDiagnosticInterface( self ):
+    if not self.DiagnosticsForCurrentFileReady():
+      return
+    self._diag_interface.UpdateWithNewDiagnostics(
+      self.GetDiagnosticsFromStoredRequest() )
+
+
   def ShowDetailedDiagnostic( self ):
     if not self._IsServerAlive():
       return