frontend: don't show new action task if namespace is deleting itself

wait for the end of the deletion of project to avoid race
condition when other action like fork or create is called
immidiatelly after delete

frontend/coprs_frontend/coprs/logic/complex_logic.py

@@ -1,5 +1,4 @@
 # coding: utf-8
-
 import os
 import datetime
 import time
@@ -126,7 +125,6 @@ def delete_expired_projects(cls):
                 print(e)
                 print("project {} postponed".format(copr.full_name))
 
-
     @classmethod
     def fork_copr(cls, copr, user, dstname, dstgroup=None):
         cls.raise_if_cant_fork(user, copr)

frontend/coprs_frontend/coprs/views/backend_ns/backend_general.py

@@ -1,5 +1,5 @@
 import flask
-from copr_common.enums import StatusEnum
+from copr_common.enums import StatusEnum, ActionTypeEnum, ActionObjectTypeEnum
 from coprs import db, app
 from coprs import models
 from coprs.logic import actions_logic
@@ -287,16 +287,34 @@ def build_task_canceled(task_id):
 @backend_ns.route("/pending-actions/")
 def pending_actions():
     'get the list of actions backand should take care of'
+    waiting_actions = actions_logic.ActionsLogic.get_waiting()
+    busy_namespaces = set()
+    for action in waiting_actions:
+        if (
+            action.object_type == ActionObjectTypeEnum.COPR
+            and action.action_type == ActionTypeEnum("delete")
+        ):
+            busy_namespaces.add(action.copr.full_name)
+
     data = []
-    for action in actions_logic.ActionsLogic.get_waiting():
+    for action in waiting_actions:
+        if (
+            action.copr.full_name in busy_namespaces
+            and action.action_type != ActionTypeEnum("delete")
+        ):
+            # e.g. copr delete _ && copr fork _; will cause race condition
+            # so don't process new action with the same namespace until delete
+            # action is processed
+            # https://github.com/fedora-copr/copr/issues/2698
+            continue
+
         data.append({
             'id': action.id,
             'priority': action.priority or action.default_priority,
         })
     return flask.json.dumps(data)
 
 
-
 @backend_ns.route("/action/<int:action_id>/")
 def get_action(action_id):
     action = actions_logic.ActionsLogic.get(action_id).one()