We now handle the starting FileReadyToParse event

The problem was that when you start vim like "vim foo.cc", the FileReadyToParse
event is sent to the server before it's actually started up. Basically, a race
condition.

We _really_ don't want to miss that event. For C++ files, it tells the server to
start compiling the file.

So now PostDataToHandlerAsync in BaseRequest will retry the request 3 times
(with exponential backoff) before failing, thus giving the server time to boot.

python/ycm/client/base_request.py

@@ -20,10 +20,15 @@
 import vim
 import json
 import requests
+from retries import retries
 from requests_futures.sessions import FuturesSession
+from concurrent.futures import ThreadPoolExecutor
 from ycm import vimsupport
 
 HEADERS = {'content-type': 'application/json'}
+# TODO: This TPE might be the reason we're shutting down slowly. It seems that
+# it waits for all worker threads to stop before letting the interpreter exit.
+EXECUTOR = ThreadPoolExecutor( max_workers = 4 )
 
 class ServerError( Exception ):
   def __init__( self, message ):
@@ -57,12 +62,24 @@ class BaseRequest( object ):
   # This returns a future! Use JsonFromFuture to get the value.
   @staticmethod
   def PostDataToHandlerAsync( data, handler ):
+    def PostData( data, handler ):
       return BaseRequest.session.post( _BuildUri( handler ),
                                       data = json.dumps( data ),
                                       headers = HEADERS )
 
+    @retries( 3, delay = 0.5 )
+    def DelayedPostData( data, handler ):
+      return requests.post( _BuildUri( handler ),
+                            data = json.dumps( data ),
+                            headers = HEADERS )
 
-  session = FuturesSession( max_workers = 4 )
+    if not _CheckServerIsHealthyWithCache():
+      return EXECUTOR.submit( DelayedPostData, data, handler )
+
+    return PostData( data, handler )
+
+
+  session = FuturesSession( executor = EXECUTOR )
   server_location = 'http://localhost:6666'
 
 
@@ -102,3 +119,22 @@ def _BuildUri( handler ):
   return ''.join( [ BaseRequest.server_location, '/', handler ] )
 
 
+SERVER_HEALTHY = False
+
+def _CheckServerIsHealthyWithCache():
+  global SERVER_HEALTHY
+
+  def _ServerIsHealthy():
+    response = requests.get( _BuildUri( 'healthy' ) )
+    response.raise_for_status()
+    return response.json()
+
+  if SERVER_HEALTHY:
+    return True
+
+  try:
+    SERVER_HEALTHY = _ServerIsHealthy()
+    return SERVER_HEALTHY
+  except:
+    return False
+

python/ycm/client/event_notification.py

@@ -17,8 +17,6 @@
 # You should have received a copy of the GNU General Public License
 # along with YouCompleteMe.  If not, see <http://www.gnu.org/licenses/>.
 
-import traceback
-from ycm import vimsupport
 from ycm.client.base_request import BaseRequest, BuildRequestData
 
 
@@ -35,15 +33,7 @@ class EventNotification( BaseRequest ):
       request_data.update( self._extra_data )
     request_data[ 'event_name' ] = self._event_name
 
-    # On occasion, Vim tries to send event notifications to the server before
-    # it's up. This causes intrusive exception messages to interrupt the user.
-    # While we do want to log these exceptions just in case, we post them
-    # quietly to the Vim message log because nothing bad will happen if the
-    # server misses some events and we don't want to annoy the user.
-    try:
     self.PostDataToHandlerAsync( request_data, 'event_notification' )
-    except:
-      vimsupport.EchoText( traceback.format_exc() )
 
 
 def SendEventNotificationAsync( event_name, extra_data = None ):