chasm visibilityTaskHandler should not be called directly

Error message

chasm visibilityTaskHandler should not be called directly

What it means

visibilityTaskHandler in chasm/visibility.go panics if its Execute method is invoked directly. Visibility tasks in CHASM must be dispatched through the framework's task processing pipeline (which routes them to the component-specific handler with the correct context), never called as a plain method. The panic is a guard against a programming error that would bypass framework invariants.

Source

Thrown at chasm/visibility.go:408

var defaultVisibilityTaskHandler = &visibilityTaskHandler{}

func (v *visibilityTaskHandler) Validate(
	_ Context,
	component *Visibility,
	_ TaskInvocation,
	task *persistencespb.ChasmVisibilityTaskData,
) (bool, error) {
	return task.TransitionCount == component.Data.TransitionCount, nil
}

func (v *visibilityTaskHandler) Execute(
	_ context.Context,
	_ ComponentRef,
	_ TaskAttributes,
	_ *persistencespb.ChasmVisibilityTaskData,
) error {
	//nolint:forbidigo
	panic("chasm visibilityTaskHandler should not be called directly")
}

View on GitHub (pinned to bde624efd1)

Solutions

Do not call visibilityTaskHandler.Execute directly; let the CHASM task framework dispatch visibility tasks
Register the handler with the CHASM framework/task registry and process tasks through the standard pipeline
If you need to drive it in tests, exercise the framework's task processing path rather than the raw method

Example fix

// before
handler := chasm.NewVisibilityTaskHandler(...)
err := handler.Execute(ctx, ref, attrs, taskData)
// after
err := chasmTaskProcessor.Process(ctx, task) // framework dispatches to the handler

Defensive patterns

Strategy: validation

Validate before calling

var _ chasm.TaskHandler = (*visibilityTaskHandler)(nil)
// never invoke Execute directly; verify dispatch goes through the task processor

Prevention

Treat all chasm task handlers as framework-internal interfaces
Process visibility tasks only via the CHASM task processor/registry
In tests, drive the framework's processing loop rather than calling handler methods

When it happens

Trigger: Calling visibilityTaskHandler.Execute(ctx, ref, attrs, taskData) directly from application code instead of registering it with the CHASM framework and letting the task processor invoke it.

Common situations: Custom task scheduling code that grabs a handler and calls Execute manually; refactoring that wires visibility tasks outside the CHASM processing loop; tests invoking the handler directly without a framework harness.

Related errors

AI-assisted analysis of temporalio/temporal@bde624efd1 (2026-09-01). Data as JSON: /api/errors/1e0f90baea9dec21. Report an issue: GitHub.