Now possible to sent Vim data to FlagsForFile func

Fixes #612.

README.md

@@ -851,6 +851,31 @@ Default: `0`
 
     let g:ycm_seed_identifiers_with_syntax = 0
 
+### The `g:ycm_extra_conf_vim_data` option
+
+If you're using semantic completion for C-family files, this option might come
+handy; it's a way of sending data from Vim to your `FlagsForFile` function in
+your `.ycm_extra_conf.py` file.
+
+This option is supposed to be a list of VimScript expression strings that are
+evaluated for every request to the `ycmd` server and then passed to your
+`FlagsForFile` function as a `client_data` keyword argument.
+
+For instance, if you set this option to `['v:version']`, your `FlagsForFile`
+function will be called like this:
+
+```python
+# The '704' value is of course contingent on Vim 7.4; in 7.3 it would be '703'
+FlagsForFile(filename, client_data = {'v:version': 704})
+```
+
+So the `client_data` parameter is a dictionary mapping Vim expression strings to
+their values at the time of the request.
+
+Default: `[]`
+
+    let g:ycm_extra_conf_vim_data = []
+
 ### The `g:ycm_server_use_vim_stdout` option
 
 By default, the `ycmd` completion server writes logs to logfiles. When this
@@ -1162,6 +1187,20 @@ Default: `1`
 FAQ
 ---
 
+### I used to be able to `import vim` in `.ycm_extra_conf.py`, but now can't
+
+YCM was rewritten to use a client-server architecture where most of the logic is
+in the `ycmd` server. So the magic `vim` module you could have previously
+imported in your `.ycm_extra_conf.py` files doesn't exist anymore.
+
+To be fair, importing the magic `vim` module in extra conf files was never
+supported in the first place; it only ever worked by accident and was never a
+part of the extra conf API.
+
+But fear not, you should be able to tweak your extra conf files to continue
+working by using the `g:ycm_extra_conf_vim_data` option. See the docs on that
+option for details.
+
 ### I get a linker warning regarding `libpython` on Mac when compiling YCM
 
 If the warning is `ld: warning: path '/usr/lib/libpython2.7.dylib' following -L

cpp/ycm/.ycm_extra_conf.py

@@ -43,6 +43,8 @@ flags = [
 '-Wno-variadic-macros',
 '-fexceptions',
 '-DNDEBUG',
+# You 100% do NOT need -DUSE_CLANG_COMPLETER in your flags; only the YCM
+# source code needs it.
 '-DUSE_CLANG_COMPLETER',
 # THIS IS IMPORTANT! Without a "-std=<something>" flag, clang won't know which
 # language to use when compiling headers. So it will guess. Badly. So C++
@@ -128,7 +130,7 @@ def MakeRelativePathsInFlagsAbsolute( flags, working_directory ):
   return new_flags
 
 
-def FlagsForFile( filename ):
+def FlagsForFile( filename, **kwargs ):
   if database:
     # Bear in mind that compilation_info.compiler_flags_ does NOT return a
     # python list, but a "list-like" StringVec object

plugin/youcompleteme.vim

@@ -112,6 +112,9 @@ let g:ycm_server_keep_logfiles =
 let g:ycm_server_idle_suicide_seconds =
       \ get( g:, 'ycm_server_idle_suicide_seconds', 43200 )
 
+let g:ycm_extra_conf_vim_data =
+      \ get( g:, 'ycm_extra_conf_vim_data', [] )
+
 
 " On-demand loading. Let's use the autoload folder and not slow down vim's
 " startup procedure.

python/ycm/client/completion_request.py

@@ -25,15 +25,15 @@ from ycm.client.base_request import ( BaseRequest, BuildRequestData,
 TIMEOUT_SECONDS = 0.5
 
 class CompletionRequest( BaseRequest ):
-  def __init__( self, force_semantic = False ):
+  def __init__( self, extra_data = None ):
     super( CompletionRequest, self ).__init__()
 
     self._completion_start_column = base.CompletionStartColumn()
 
     # This field is also used by the omni_completion_request subclass
     self.request_data = BuildRequestData( self._completion_start_column )
-    if force_semantic:
-      self.request_data[ 'force_semantic' ] = True
+    if extra_data:
+      self.request_data.update( extra_data )
 
 
   def CompletionStartColumn( self ):

python/ycm/completers/cpp/clang_completer.py

@@ -247,7 +247,8 @@ class ClangCompleter( Completer ):
     if 'compilation_flags' in request_data:
       return PrepareFlagsForClang( request_data[ 'compilation_flags' ],
                                    filename )
-    return self._flags.FlagsForFile( filename )
+    client_data = request_data.get( 'extra_conf_data', None )
+    return self._flags.FlagsForFile( filename, client_data = client_data )
 
 
 def ConvertCompletionData( completion_data ):

python/ycm/completers/cpp/flags.py

@@ -19,6 +19,7 @@
 
 import ycm_core
 import os
+import inspect
 from ycm import extra_conf_store
 from ycm.utils import ToUtf8IfNeeded
 
@@ -40,7 +41,10 @@ class Flags( object ):
     self.no_extra_conf_file_warning_posted = False
 
 
-  def FlagsForFile( self, filename, add_special_clang_flags = True ):
+  def FlagsForFile( self,
+                    filename,
+                    add_special_clang_flags = True,
+                    client_data = None ):
     try:
       return self.flags_for_file[ filename ]
     except KeyError:
@@ -51,7 +55,9 @@ class Flags( object ):
           raise RuntimeError( NO_EXTRA_CONF_FILENAME_MESSAGE )
         return None
 
-      results = module.FlagsForFile( filename )
+      results = _CallExtraConfFlagsForFile( module,
+                                            filename,
+                                            client_data )
 
       if not results.get( 'flags_ready', True ):
         return None
@@ -95,6 +101,15 @@ class Flags( object ):
     self.flags_for_file.clear()
 
 
+def _CallExtraConfFlagsForFile( module, filename, client_data ):
+  # For the sake of backwards compatibility, we need to first check whether the
+  # FlagsForFile function in the extra conf module even allows keyword args.
+  if inspect.getargspec( module.FlagsForFile ).keywords:
+    return module.FlagsForFile( filename, client_data = client_data )
+  else:
+    return module.FlagsForFile( filename )
+
+
 def PrepareFlagsForClang( flags, filename ):
   flags = _RemoveUnusedFlags( flags, filename )
   flags = _SanitizeFlags( flags )

python/ycm/completers/cpp/tests/flags_test.py

@@ -18,8 +18,6 @@
 # along with YouCompleteMe.  If not, see <http://www.gnu.org/licenses/>.
 
 from nose.tools import eq_
-from ycm.test_utils import MockVimModule
-vim_mock = MockVimModule()
 from .. import flags
 
 

python/ycm/server/tests/get_completions_test.py

@@ -24,7 +24,7 @@ import httplib
 from .test_utils import Setup, BuildRequest, PathToTestFile
 from webtest import TestApp
 from nose.tools import eq_, with_setup
-from hamcrest import ( assert_that, has_items, has_entry,
+from hamcrest import ( assert_that, has_item, has_items, has_entry,
                        contains_inanyorder )
 from ..responses import BuildCompletionData, UnknownExtraConf
 from .. import handlers
@@ -211,6 +211,28 @@ def GetCompletions_ForceSemantic_Works_test():
                                    CompletionEntryMatcher( 'bool' ) ) )
 
 
+@with_setup( Setup )
+def GetCompletions_ClangCompleter_ClientDataGivenToExtraConf_test():
+  app = TestApp( handlers.app )
+  app.post_json( '/load_extra_conf_file',
+                 { 'filepath': PathToTestFile(
+                                  'client_data/.ycm_extra_conf.py' ) } )
+
+  filepath = PathToTestFile( 'client_data/main.cpp' )
+  completion_data = BuildRequest( filepath = filepath,
+                                  filetype = 'cpp',
+                                  contents = open( filepath ).read(),
+                                  line_num = 8,
+                                  column_num = 6,
+                                  start_column = 6,
+                                  extra_conf_data = {
+                                    'flags': ['-x', 'c++']
+                                  })
+
+  results = app.post_json( '/completions', completion_data ).json
+  assert_that( results, has_item( CompletionEntryMatcher( 'x' ) ) )
+
+
 @with_setup( Setup )
 def GetCompletions_IdentifierCompleter_SyntaxKeywordsAdded_test():
   app = TestApp( handlers.app )

python/ycm/server/tests/testdata/client_data/.ycm_extra_conf.py

@@ -0,0 +1,5 @@
+def FlagsForFile( filename, **kwargs ):
+  return {
+    'flags': kwargs['client_data']['flags'],
+    'do_cache': True
+  }

python/ycm/server/tests/testdata/client_data/main.cpp

@@ -0,0 +1,11 @@
+struct Foo {
+  int x;
+};
+
+int main()
+{
+  Foo foo;
+  // The location after the dot is line 9, col 7
+  foo.
+}
+

python/ycm/vimsupport.py

@@ -118,6 +118,16 @@ def GetReadOnlyVimGlobals( force_python_objects = False ):
     return vim.eval( 'g:' )
 
 
+def VimExpressionToPythonType( vim_expression ):
+  result = vim.eval( vim_expression )
+  if not isinstance( result, basestring ):
+    return result
+  try:
+    return int( result )
+  except ValueError:
+    return result
+
+
 # Both |line| and |column| need to be 1-based
 def JumpToLocation( filename, line, column ):
   # Add an entry to the jumplist

python/ycm/youcompleteme.py

@@ -132,7 +132,12 @@ class YouCompleteMe( object ):
          self._omnicomp.ShouldUseNow() ):
       self._latest_completion_request = OmniCompletionRequest( self._omnicomp )
     else:
-      self._latest_completion_request = ( CompletionRequest( force_semantic )
+      extra_data = {}
+      self._AddExtraConfDataIfNeeded( extra_data )
+      if force_semantic:
+        extra_data[ 'force_semantic' ] = True
+
+      self._latest_completion_request = ( CompletionRequest( extra_data )
                                           if self._IsServerAlive() else
                                           None )
     return self._latest_completion_request
@@ -176,11 +181,9 @@ class YouCompleteMe( object ):
       self._NotifyUserIfServerCrashed()
 
     extra_data = {}
-    if self._user_options[ 'collect_identifiers_from_tags_files' ]:
-      extra_data[ 'tag_files' ] = _GetTagFiles()
-
-    if self._user_options[ 'seed_identifiers_with_syntax' ]:
-      self._AddSyntaxDataIfNeeded( extra_data )
+    self._AddTagsFilesIfNeeded( extra_data )
+    self._AddSyntaxDataIfNeeded( extra_data )
+    self._AddExtraConfDataIfNeeded( extra_data )
 
     self._latest_file_parse_request = EventNotification( 'FileReadyToParse',
                                                           extra_data )
@@ -280,6 +283,8 @@ class YouCompleteMe( object ):
 
 
   def _AddSyntaxDataIfNeeded( self, extra_data ):
+    if not self._user_options[ 'seed_identifiers_with_syntax' ]:
+      return
     filetype = vimsupport.CurrentFiletypes()[ 0 ]
     if filetype in self._filetypes_with_keywords_loaded:
       return
@@ -289,10 +294,26 @@ class YouCompleteMe( object ):
        syntax_parse.SyntaxKeywordsForCurrentBuffer() )
 
 
-def _GetTagFiles():
-  tag_files = vim.eval( 'tagfiles()' )
-  current_working_directory = os.getcwd()
-  return [ os.path.join( current_working_directory, x ) for x in tag_files ]
+  def _AddTagsFilesIfNeeded( self, extra_data ):
+    def GetTagFiles():
+      tag_files = vim.eval( 'tagfiles()' )
+      current_working_directory = os.getcwd()
+      return [ os.path.join( current_working_directory, x ) for x in tag_files ]
+
+    if not self._user_options[ 'collect_identifiers_from_tags_files' ]:
+      return
+    extra_data[ 'tag_files' ] = GetTagFiles()
+
+
+  def _AddExtraConfDataIfNeeded( self, extra_data ):
+    def BuildExtraConfData( extra_conf_vim_data ):
+      return dict( ( expr, vimsupport.VimExpressionToPythonType( expr ) )
+                   for expr in extra_conf_vim_data )
+
+    extra_conf_vim_data = self._user_options[ 'extra_conf_vim_data' ]
+    if extra_conf_vim_data:
+      extra_data[ 'extra_conf_data' ] = BuildExtraConfData(
+        extra_conf_vim_data )
 
 
 def _PathToServerScript():