You attempted to update `numRunning` on `<Task:[TASK_NAME]>`, but it had already been used previously in the same computation.

Hey there, I’m getting some strange error when trying to use the isRunning property on the Task (not the TaskInstance)

This is the full error:

backburner.js:352 Error: Assertion Failed: You attempted to update `numRunning` on `<Task:renderStructure>`, but it had already been used previously in the same computation.  Attempting to update a value after using it in a computation can cause logical errors, infinite revalidation bugs, and performance issues, and is not supported.

numRunning` was first used:

- While rendering:
  
  application
    brands
      brands.brand-version
        brands.brand-version.print-store
          application
            designs
              business-card-sample
                this.renderStructure.isRunning

Stack trace for the update:
    at dirtyTagFor (validator.js:541)
    at markObjectAsDirty (index.js:546)
    at notifyPropertyChange (index.js:584)
    at Object.set (index.js:1530)
    at Class._startTaskInstance (-scheduler.js:106)
    at Class._flushQueues (-scheduler.js:81)
    at Class.schedule (-scheduler.js:63) undefined

My code looks like this:

{{#if this.renderStructure.isRunning}}
   // ... Do stuff
{{/if}}
<ChildComponent @renderStructure={{this.renderStructure}}/>
<ChildComponent @renderStructure={{this.renderStructure}}/>

I have a parent component that passes the task renderStructure to two identical child components. I want to able to tell once all child component finish processing.

My env: ember-cli: “3.20.0” ember-source: “3.20.5” ember-concurrency: “1.3.0”, ember-concurrency-decorators: “2.0.1”,

[yoavfranco]

In the meantime I’ve done a very poor workaround (that works) by replacing this:

{{#if this.renderStructure.isRunning}}
   // ... Do stuff
{{/if}}

With this:

{{#if (not (eq this.renderStructure.performCount 2))}}
   // ... Do stuff
{{/if}}

[maxfierke]

hmmm… nothing stands out as problematic there. If you could put together an Ember Twiddle, a failing test, or a GitHub repo that reproduces it, that would be aces! Otherwise, I can try to put something together in the next week or so to see if I can reproduce it and dig into it.