SUCCESSORS Testing

@Paul Newcome - This thread and its comments are outstanding, thank you! Like @Vivien Chong, I am using this principle to identify my Next Assignee ("Assigned to" field). Since we all appear to be blocked when it comes to referencing data where more than one Successor exists, is there a way to call out this risk via error text? I envision an amendment to my existing formula that identifies when a comma exists in the Successor field to say "Multiple", I just don't know where to start. Here's my formula...

=IF(Successor@row <> "", JOIN(COLLECT([Assigned To]:[Assigned To], Row:Row, HAS(Successor@row, @cell)), CHAR(10)))

Jumping in well in advance after you guys have done a ton of work on this topic. Is what is laid out in this thread still the 'best' option with the current functionality or have there been any new developments that have made this more 'out of the box'? I've got a colleague requesting the automated notification to the 'next' task owner and am liking what @Jason.Darr has shared above to at least have an error for the multi-successor option that can be handled uniquely to make sure someone takes action. @Paul Newcome @Vivien Chong

See Paul Newcome's post from 10/21/21 for the following three bullets:

1. Add the "Auto" field // auto-numbering the rows
2. Add the "Row" field // =MATCH(Auto@row, Auto:Auto, 0) // gives me the row number matching with the sheet
3. Add the "Next Tasks" field // =JOIN(SUCCESSORS([Task Name]@row), CHAR(10))
   1. The other version from Vivien Chong wasn't displaying each as unique entries. Not sure if I am/was missing something with that

Then I added a couple more columns (the first of which I'm not sure is needed or how it's used) from Paul Newcome's 1/12/22 post:

1. Added the "Successor" field // =SUBSTITUTE([Next Tasks]@row, ", ", CHAR(10))
2. Added the "Successor Task Name" field // =JOIN(COLLECT([Task Name]:[Task Name], Row:Row, HAS(Predecessor@row, @cell)), CHAR(10))

Then I needed to populate the Assigned To for the Successor Task to create an automated workflow to notify them when their task is ready for them.

1. Added the "Successor Assigned To" field // =IFERROR(INDEX([Assigned To]:[Assigned To], MATCH([Successor Task Name]@row, [Task Name]:[Task Name], 0)), "Notify PM")

Running into issues with the multiple Predecessors, but the IFERROR function in the above formula to have a value of "Notify PM" in the field with a corresponding Automation Workflow to alert the PM who can manually alert the person/s on deck for the next tasks. This can be tailored to the needs of the project; the task owner could be notified as well to alert the next in line. I'll see what the person running this sheet desires.

This post is largely for me to lay out what I had to do to make this work for my internal stakeholder, but also to seek out any additional guidance here.