hashicorp/nomad · error

can not diff tasks with different names: %q and %q

Error message

can not diff tasks with different names: %q and %q

What it means

Task.Diff refuses to compare two non-nil tasks with different names; task diffs are only defined for the same task name across job versions.

Source

Thrown at nomad/structs/diff.go:466

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

	// Diff the primitive fields.
	diff.Fields = fieldDiffs(oldPrimitiveFlat, newPrimitiveFlat, false)

	// Constraints diff
	conDiff := primitiveObjectSetDiff(
		interfaceSlice(t.Constraints),
		interfaceSlice(other.Constraints),
		[]string{"str"},
		"Constraint",
		contextual)
	if conDiff != nil {
		diff.Objects = append(diff.Objects, conDiff...)

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Diff tasks with matching names
2. Represent added/deleted tasks with a nil side instead of different names

When it happens

Trigger: Thrown at nomad/structs/diff.go:466 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/1759da48dbb6108e. Report an issue: GitHub.