Multiple executions of activities after WaitAny Join when using multiple loops before it

[ispasoiurobert]

Description

Even if the join is on WaitAny mode, for any canceled loop activity that enters in it, the join gets executed once more ( with all the activities after it ).
See below.

1. Detailed Steps: Add a fork with multiple branches. Add one loop activity on every branch. ( it does not matter the type of loop, it reproduces for all ). Add anything in those loops ( in my case: delay and WriteLines ). Have one of those loops finish first. Connect those to a WaitAny Join. Add any activity after the join.

2. Code Snippets: src/modules/Elsa.Workflows.Core/Activities/Flowchart/Activities/FlowJoin.cs:52case FlowJoinMode.WaitAny: { Flowchart.CancelAncestorActivatesAsync(context); await context.CompleteActivityAsync(); break; }
   For the first loop that completes, the join is also completed ( completedAt field is set and also the status is set ).
   When the second loop is canceled, that part of code is executed once more, but this time the join execution context does not have the last status set ( it will get completed once again ).
   For the third loop that is canceled, there is a new join activity context created so that part of code is once again executed and the join is completed once more.
   ( in the screenshot, there are 2 executions shown for the join activity, bcs there were 2 activity context created, but activities after it will be executed 3 times ).

3. Attachments:

   • Workflow JSON: https://pastebin.com/rDruscJW ( test workflow json ) ( check the pastebin link ).

4. Reproduction Rate: everytime.

Expected Behavior

One loop to be completed and the other 2 to be canceled.
Only one execution of Join.
Only one execution for the activities after Join.

Actual Behavior

First loop is completed ✔️
The other 2 loops are canceled ✔️, but they are marked as completed ( see screenshot ). ❌
Multiple executions of Join. ❌
Multiple executions for the activities after Join. ❌

Screenshots

Environment

• Elsa Package Version: branch: patch/3.5.1, but also on version 3.4.2.
• Operating System: Windows 11.
• Browser and Version: Chrome 140.

[popescumadalin0]

@ispasoiurobert @sfmskywalker
I think I found what’s happening:
Basically, when the Join cancels the inbound activities, the foreach completion callback gets triggered, and it reaches the Join activity before the previous context has finished completing. Please check the images:

[sfmskywalker]

Hi @popescumadalin0 , thanks for the detailed report.
There are definitely issues with the joining logic in <=3.5.1 and has been completely rewritten as of 3.6.0 (preview).
Maybe you check with 3.6.0-preview.{xxx}?

[ispasoiurobert]

just tested with version 3.6.0 from develop branch and set merge mode to race value for the writeline. writeline executed only once which is correct, but the loop before it, that should have been canceled, is shown as completed, for the same reason that @popescumadalin0 pointed out ( completion callbacks are canceled after the children of the loop have been canceled first ). also tested with multiple delays activities and it seems that the workflow does not work properly ( converge mode is on race ).