Function requestUpdateLane

packages/react-reconciler/src/ReactFiberWorkLoop.js:792–836

(fiber: Fiber)

}

export function requestUpdateLane(fiber: Fiber): Lane {
  // Special cases
  const mode = fiber.mode;
  if (!disableLegacyMode && (mode & ConcurrentMode) === NoMode) {
    return (SyncLane: Lane);
  } else if (
    (executionContext & RenderContext) !== NoContext &&
    workInProgressRootRenderLanes !== NoLanes
  ) {
    // This is a render phase update. These are not officially supported. The
    // old behavior is to give this the same "thread" (lanes) as
    // whatever is currently rendering. So if you call `setState` on a component
    // that happens later in the same render, it will flush. Ideally, we want to
    // remove the special case and treat them as if they came from an
    // interleaved event. Regardless, this pattern is not officially supported.
    // This behavior is only a fallback. The flag only exists until we can roll
    // out the setState warning, since existing code might accidentally rely on
    // the current behavior.
    return pickArbitraryLane(workInProgressRootRenderLanes);
  }

  const transition = requestCurrentTransition();
  if (transition !== null) {
    if (enableGestureTransition) {
      if (transition.gesture) {
        throw new Error(
          'Cannot setState on regular state inside a startGestureTransition. ' +
            'Gestures can only update the useOptimistic() hook. There should be no ' +
            'side-effects associated with starting a Gesture until its Action is ' +
            'invoked. Move side-effects to the Action instead.',
        );
      }
    }
    if (__DEV__) {
      if (!transition._updatedFibers) {
        transition._updatedFibers = new Set();
      }
      transition._updatedFibers.add(fiber);
    }

    return requestTransitionLane(transition);
  }

  return eventPriorityToLane(resolveUpdatePriority());
}

function requestRetryLane(fiber: Fiber) {
  // This is a fork of `requestUpdateLane` designed specifically for Suspense