hashicorp/nomad · error

can not diff task groups with different names: %q and %q

Error message

can not diff task groups with different names: %q and %q

What it means

TaskGroup.Diff refuses to compare two non-nil task groups with different names; a diff is only meaningful between versions of the same named group.

Source

Thrown at nomad/structs/diff.go:245

	if tg == nil && other == nil {
		return diff, nil
	} else if tg == nil {
		tg = &TaskGroup{}
		diff.Type = DiffTypeAdded
		diff.Name = other.Name
		newPrimitiveFlat = flatmap.Flatten(other, filter, true)
	} else if other == nil {
		other = &TaskGroup{}
		diff.Type = DiffTypeDeleted
		diff.Name = tg.Name
		oldPrimitiveFlat = flatmap.Flatten(tg, filter, true)
	} else {
		if !reflect.DeepEqual(tg, other) {
			diff.Type = DiffTypeEdited
		}
		if tg.Name != other.Name {
			return nil, fmt.Errorf("can not diff task groups with different names: %q and %q", tg.Name, other.Name)
		}
		diff.Name = other.Name
		oldPrimitiveFlat = flatmap.Flatten(tg, filter, true)
		newPrimitiveFlat = flatmap.Flatten(other, filter, true)
	}

	// ShutdownDelay diff
	if oldPrimitiveFlat != nil && newPrimitiveFlat != nil {
		if tg.ShutdownDelay == nil {
			oldPrimitiveFlat["ShutdownDelay"] = ""
		} else {
			oldPrimitiveFlat["ShutdownDelay"] = fmt.Sprintf("%d", *tg.ShutdownDelay)
		}
		if other.ShutdownDelay == nil {
			newPrimitiveFlat["ShutdownDelay"] = ""
		} else {
			newPrimitiveFlat["ShutdownDelay"] = fmt.Sprintf("%d", *other.ShutdownDelay)
		}

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Diff task groups with matching names
2. Handle add/remove via a nil side rather than mismatched names

When it happens

Trigger: Thrown at nomad/structs/diff.go:245 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/8fd16f7e2578c7f0. Report an issue: GitHub.