tree: tree view differs from table view

[oliver-sanders]

We have received multiple reports of discrepancies between the tree and table views.

In the most recent report a task was showing in tree view as submitted, but in the table view as succeeded (correct).

In all cases the table view was showing the correct data so this would appear to be a tree-view bug. It has not yet been confirmed whether the graph view matches the tree or table but I suspect it will match the table.

The tree view follows the "node.familyTree" down to the task whereas table/graph views are not interested in this information so use "node.children". So this is likely related to inheritance. We had a previous bug where task ancestors were coming out in an unstable order, this may be similar.

To debug suggest:

• Take a reported example and attempting to reproduce on the reported task (this might not be reproducible in any old workflow with any old task).
• Try restarting the workflow if struggling to reproduce in case this is a random order / race condition bug in cylc-flow.
• Once reproduced, inspect the vuex store drilling down to the familyTree of the cycle point the task is in.
• If the tree view matches the familyTree, then the tree view has done what it was told to.
  • The bug is either in the ui-data-store(src/store/workflows.module.js), or the cylc-flow data store.
  • Use GraphiQL to inspect ancestors { name } and child tasks { id } to determine which.
• If the tree view differs from the familyTree then it is a reactivity problem in src/components/cylc/tree/Tree[Item].vue.

[oliver-sanders]

Have managed to replicate this issue with the following workflow:

[task parameters]                                              
    x = 1..2                                                   

[scheduling]                                                   
    [[graph]]                                                  
        R1 = """                                               
            a<x> => b<x> => c<x>                                                                                                   
        """                                                    

[runtime]                                                      
    [[A,B,C]]                                  
    [[a<x>]]                                                   
        inherit = A                                            
    [[b<x>]]                                                   
        inherit = B                                            
    [[b<x=1>]]                                                 
        script = false                                         
    [[c<x>]]                                                   
        inherit = C                                            

Note the two tasks which are lacking jobs which appear in the tree view. These do not appear in the table or graph views nor Tui.

[oliver-sanders]

The UI data-store is expecting the list of childTasks received in delta-updates to always be complete. It's possible that the cylc-flow data store is only listing the updated children in each update which could be causing this.

The UI data store relied on this field, both for adding tasks to families in the familyTree and also for removing them. I think we could rely on the pruned delta for the removals which would bypass this problem if true.