Loop in approve() Function

[jasondalycan]

I have a workflow that has two cyclic paths (which River supports as per the documentation) but when invoking the approve(as_user, next_stage_id) function the database is queries in an infinite loop causing lock wait timeouts and the application comes to a halt. I've looked through the code and have identified the culprit function to be _re_create_cycled_path() within instanceworkflowobject.py where it loops infinitely within the while old_transitions: loop. It appears that the loop continuously creates cycle_transitions dynamically and then loops through them indefinitely declaring them as old_transitions.

I've implemented a patch whereby I end the loop once it begins looping through the cycle_transitions. Can you please confirm if this is indeed a bug (or a workflow pattern unsupported by River at this time and if it is a bug I can contribute the patch I've developed as needed.

Attached is a diagram of the workflow I have created (I've obfuscated some of the step names although they are all unique stages and not duplicates):

[cyberdude86]

I seem to have run into the same issue with a very simple return to initial state scenario.

Queue->assign
Assign->review
Review->reject
Review->complete
Reject->queue

[jasondalycan]

@cyberdude86 try this fix. See lines 276, 296 and 317 as the primary methods of fixing this loop (detecting the 'cycled_transitions' and excluding them with a filter). Please note that I've added a number of print() debug statements which can be ignored. To use this file please do the following:

• Backup /usr/local/lib/python3.6/site-packages/river/core/instanceworkflowobject.py (this is where River is installed on CentOS 8)

• Unzip the attached file (instanceworkflowobject.zip which contains an updated version of instanceworkflowobject.py

• Overwrite this file with the attached file (instanceworkflowobject.py)

• Rerun your workflow

Please let me know if this resolves your issue:

instanceworkflowobject.zip

[debugskeleton]

new issue alt account for @cyberdude86

workflow stop unexpectedly here is the approvals exported

'[{"model": "river.transition", "pk": 604, "fields": {"date_created": "2020-05-24T02:01:49.407Z", "date_updated": "2020-05-24T02:01:52.377Z", "content_type": 3, "object_id": " 96", "meta": 13, "workflow": 2, "source_state": 1, "destination_state": 3, "status": "done", "iteration": 0}}, {"model": "river.transition", "pk": 605, "fields": {"date_create d": "2020-05-24T02:01:49.422Z", "date_updated": "2020-05-24T02:01:53.881Z", "content_type": 3, "object_id": "96", "meta": 15, "workflow": 2, "source_state": 3, "destination_st ate": 4, "status": "done", "iteration": 1}}, {"model": "river.transition", "pk": 606, "fields": {"date_created": "2020-05-24T02:01:49.456Z", "date_updated": "2020-05-24T02:01: 57.250Z", "content_type": 3, "object_id": "96", "meta": 17, "workflow": 2, "source_state": 4, "destination_state": 2, "status": "done", "iteration": 2}}, {"model": "river.tran sition", "pk": 607, "fields": {"date_created": "2020-05-24T02:01:49.473Z", "date_updated": "2020-05-24T02:01:57.244Z", "content_type": 3, "object_id": "96", "meta": 21, "workf low": 2, "source_state": 4, "destination_state": 7, "status": "cancelled", "iteration": 2}}, {"model": "river.transition", "pk": 608, "fields": {"date_created": "2020-05-24T02 :01:49.477Z", "date_updated": "2020-05-24T02:01:57.244Z", "content_type": 3, "object_id": "96", "meta": 26, "workflow": 2, "source_state": 4, "destination_state": 8, "status": "cancelled", "iteration": 2}}, {"model": "river.transition", "pk": 609, "fields": {"date_created": "2020-05-24T02:01:49.485Z", "date_updated": "2020-05-24T02:01:58.590Z", "co ntent_type": 3, "object_id": "96", "meta": 20, "workflow": 2, "source_state": 2, "destination_state": 7, "status": "done", "iteration": 3}}, {"model": "river.transition", "pk" : 610, "fields": {"date_created": "2020-05-24T02:01:49.498Z", "date_updated": "2020-05-24T02:01:57.245Z", "content_type": 3, "object_id": "96", "meta": 24, "workflow": 2, "sou rce_state": 7, "destination_state": 3, "status": "cancelled", "iteration": 3}}]'

[javrasya]

Let me see what is the problem with your flow and get back to you guys.

[jasondalycan]

@javrasya any luck with this?

[javrasya]

Hi @jasondalycan and @cyberdude86 , There is a bug in django-river as you stated above. When there are more than one cyclic dependencies in a workflow, it goes into an infinite circuilar loop when the first cyclic transition goes through. This PR should fix your problem. I will release that change as soon as possible. So please follow it up and update django-river version in your projects when it is released.

Sorry for the late patching. I didn't have time to look into it. I also referred to your workflow in a feature test in order to reproduce it @jasondalycan , hope you don't mind it.

[javrasya]

Hi again, the new patch version that contains the fix has just been released. Update django-river version in your projects to be 3.2.1 please.

https://github.com/javrasya/django-river/releases/tag/3.2.1

[javrasya]

Feel free to create a new ticket if the fix doesn't solve your problem

[ampotty]

the cyclic transition is not working now.We have A->B , B->A, B->C , B->D..