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Post by lakshminarayana »

I would like to automatically adjust the project's start date by increasing the duration of Task 1 or the Task Fixed end date. Simultaneously, I want to be able to change the project's end date by increasing the duration of Task 3.

Current behavior: Increasing the duration of Task 1 or the Task Fixed end date does not yield any results, while increasing the duration of Task 3 changes the project's end date.

Below, I am providing the configuration details.

export const ganttPropsStartDate = {
    columns: [{ type: "name", field: "name", width: 250 }],
    viewPreset: "weekAndDayLetter",
    barMargin: 10,
    displaySchedulingIssueResolutionPopup: false,
    project: {
      startDate: "2024-07-03",
      tasksData: [
        {
          id: 0,
          children: [
            {
              id: 1,
              direction: "Backward",
              name: "Task 1",
              duration: 3,
              projectConstraintResolution: "ignore",
            },
            {
              id: 2,
              constraintType: "mustfinishon",
              constraintDate: "2024-07-09",
              name: "Task Fixed end date",
              duration: 3,
              projectConstraintResolution: "ignore",
            },
            {
              id: 3,
              direction: "Forward",
              name: "Task 3",
              duration: 3,
              projectConstraintResolution: "ignore",
            },
          ]
        }
      ],
      dependenciesData: [
        { id: 1, fromTask: 1, toTask: 2 },
        { id: 2, fromTask: 2, toTask: 3 },
      ],
    },
  };
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Post by ghulam.ghous »

Hi there,

I would like to automatically adjust the project's start date by increasing the duration of Task 1 or the Task Fixed end date.

That is not possible in the forward scheduling mode. Because in forward direction, all the events have a Start no earlier than constraint.

In a forward scheduled project (default), the Gantt engine schedules events as soon as possible (ASAP). For such projects, the start date is mandatory and sets an implicit Start no earlier than constraint (see constraint details in below chapters) inherited by all events.

Please read more about it here: https://bryntum.com/products/gantt/docs/api/Gantt/model/ProjectModel#field-direction and https://bryntum.com/products/gantt/docs/guide/engine/gantt_events_scheduling#forward-scheduled-project

So changing duration for Task Fixed does not do anything as you have set mustfinishon constraint on that event. You can only use one scheduling type, backward or forward. Please read docs provided for more clarity.


Post by lakshminarayana »

Thanks for quick response :) In this case i have one follow-up question. Is there a way to ignore Start date using task direction, and projectConstraintResolution?


Post by marcio »

Hey,

You can set https://bryntum.com/products/gantt/docs/api/SchedulerPro/model/EventModel#field-manuallyScheduled to true on the events that you want to ignore the incoming dependencies or constraints.

Best regards,
Márcio


Post by lakshminarayana »

Hello again,

We have attempted all your recommendations, yet there's no success with version 5.2.4. However, when we isolated the problematic code segment and tested it in a different environment with version 6.0.4. It functioned correctly.

The main issue is that migrating to this version of Bryntum Gantt is not feasible (at the moment) due to numerous risks. (deprecation notice, breaking changes introduced in v6)

Our foremost objective is to minimize the risk associated with migration. Ideally, we would prefer to upgrade to a sub-version of 5.X.X that resolves the aforementioned issue.

Could you assist us by indicating which sub-version of 5 contains the necessary fix?

Thank you, a lot!


Post by marcio »

Hey lakshminarayana,

Which fix are you referring to? Try upgrading minor versions first (5.3, 5.4), I believe it should serve you better.

Best regards,
Márcio


Post by lakshminarayana »

Hi marcio,

Kindly thank you for your answer! So, it seems as if we should go step by step.

Below is the description of the issue:

When one of the tasks in the Bryntum Gantt chart has a "mustFinishOn" constraint, we expect:

  1. Tasks before the "mustFinishOn" task: These tasks should have a "backward" direction and no constraints. Their end dates should adjust according to the start date of the "mustFinishOn" task.
  2. Tasks after the "mustFinishOn" task: These tasks should follow a "forward" direction, starting only after the "mustFinishOn" task is completed.

Our Issue:

  1. The tasks before the "mustFinishOn" task (with a backward direction) should adjust their end dates based on the start date of the "mustFinishOn" task.
  2. However, the task immediately before the "mustFinishOn" task does not automatically adjust its end date to align with the start date of the "mustFinishOn" task.

This misalignment causes scheduling conflicts and disrupts the expected flow of task dependencies, as the end date of the task before the "mustFinishOn" task remains fixed instead of dynamically updating based on the constrained task’s start date.

Thank you!


Post by alex.l »

Hi lakshminarayana,

Project's startDate is a fixed value for forward scheduled projects. It cannot be recalculated because of data, you only can manually change it if you need. This is by design and cannot be easily changed, it requires to patch Scheduling Engine. If you need that behaviour, please contact our Sales for Professional Services https://bryntum.com/services

All the best,
Alex


Post by nickolay »

@lakshminarayana Hi,

We have attempted all your recommendations, yet there's no success with version 5.2.4. However, when we isolated the problematic code segment and tested it in a different environment with version 6.0.4. It functioned correctly.

Can you please provide the example you were testing? The description of the issue is not quite clear.

Tasks before the "mustFinishOn" task: These tasks should have a "backward" direction and no constraints

We actually never had this feature, the direction flag of the predecessor task is not affected by the successor constraint type. So its not quite clear how it could work in v6.0.4.

Please provide a reproducible test case for this issue along with the detailed steps to reproduce. Please specify the result you receive and result you expect.


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