Fixes chord bug when processing IGNORED tasks

Should not run on_chord_part_return, task_after_return,
nor send_postrun when task was IGNORED or RETRIED

celery/task/trace.py

@@ -47,6 +47,7 @@ IGNORED = states.IGNORED
 RETRY = states.RETRY
 FAILURE = states.FAILURE
 EXCEPTION_STATES = states.EXCEPTION_STATES
+IGNORE_STATES = frozenset([IGNORED, RETRY])
 
 #: set by :func:`setup_worker_optimizations`
 _tasks = None
@@ -142,7 +143,8 @@ class TraceInfo(object):
 
 
 def build_tracer(name, task, loader=None, hostname=None, store_errors=True,
-                 Info=TraceInfo, eager=False, propagate=False):
+                 Info=TraceInfo, eager=False, propagate=False,
+                 IGNORE_STATES=IGNORE_STATES):
     """Builts a function that tracing the tasks execution; catches all
     exceptions, and saves the state and result of the task execution
     to the result backend.
@@ -227,7 +229,8 @@ def build_tracer(name, task, loader=None, hostname=None, store_errors=True,
                     state = SUCCESS
                 except Ignore, exc:
                     I, R = Info(IGNORED, exc), ExceptionInfo(internal=True)
-                except RetryTaskError, exc:
+                    state, retval = I.state, I.retval
+                except RetryTaskError,  exc:
                     I = Info(RETRY, exc)
                     state, retval = I.state, I.retval
                     R = I.handle_error_state(task, eager=eager)
@@ -264,14 +267,15 @@ def build_tracer(name, task, loader=None, hostname=None, store_errors=True,
                         send_success(sender=task, result=retval)
 
                 # -* POST *-
-                if task_request.chord:
-                    on_chord_part_return(task)
-                if task_after_return:
-                    task_after_return(state, retval, uuid, args, kwargs, None)
-                if postrun_receivers:
-                    send_postrun(sender=task, task_id=uuid, task=task,
-                                 args=args, kwargs=kwargs,
-                                 retval=retval, state=state)
+                if state not in IGNORE_STATES:
+                    if task_request.chord:
+                        on_chord_part_return(task)
+                    if task_after_return:
+                        task_after_return(state, retval, uuid, args, kwargs, None)
+                    if postrun_receivers:
+                        send_postrun(sender=task, task_id=uuid, task=task,
+                                     args=args, kwargs=kwargs,
+                                     retval=retval, state=state)
             finally:
                 pop_task()
                 pop_request()