Protect the system from when one attempts to start a job without an inventory

awx/main/models/jobs.py

@@ -417,6 +417,8 @@ class Job(UnifiedJob, JobOptions):
 
     def generate_dependencies(self, active_tasks):
         from awx.main.models import InventoryUpdate, ProjectUpdate
+        if self.inventory is None or self.project is None:
+            return []
         inventory_sources = self.inventory.inventory_sources.filter(active=True, update_on_launch=True)
         project_found = False
         inventory_sources_found = []

awx/main/signals.py

@@ -102,7 +102,8 @@ def emit_update_inventory_on_created_or_deleted(sender, **kwargs):
     except Inventory.DoesNotExist:
         pass
     else:
-        update_inventory_computed_fields.delay(inventory.id, True)
+        if inventory is not None:
+            update_inventory_computed_fields.delay(inventory.id, True)
 
 def store_initial_active_state(sender, **kwargs):
     instance = kwargs['instance']

awx/main/tasks.py

@@ -163,6 +163,7 @@ def update_inventory_computed_fields(inventory_id, should_update_hosts=True):
     i = Inventory.objects.filter(id=inventory_id)
     if not i.exists():
         logger.error("Update Inventory Computed Fields failed due to missing inventory: " + str(inventory_id))
+        return
     i = i[0]
     i.update_computed_fields(update_hosts=should_update_hosts)