Function updateCacheComponent

packages/react-reconciler/src/ReactFiberBeginWork.js:1214–1278

(
  current: Fiber | null,
  workInProgress: Fiber,
  renderLanes: Lanes,
)

}

function updateCacheComponent(
  current: Fiber | null,
  workInProgress: Fiber,
  renderLanes: Lanes,
) {
  prepareToReadContext(workInProgress, renderLanes);
  const parentCache = readContext(CacheContext);

  if (current === null) {
    // Initial mount. Request a fresh cache from the pool.
    const freshCache = requestCacheFromPool(renderLanes);
    const initialState: CacheComponentState = {
      parent: parentCache,
      cache: freshCache,
    };
    workInProgress.memoizedState = initialState;
    initializeUpdateQueue(workInProgress);
    pushCacheProvider(workInProgress, freshCache);
  } else {
    // Check for updates
    if (includesSomeLane(current.lanes, renderLanes)) {
      cloneUpdateQueue(current, workInProgress);
      processUpdateQueue(workInProgress, null, null, renderLanes);
      suspendIfUpdateReadFromEntangledAsyncAction();
    }
    const prevState: CacheComponentState = current.memoizedState;
    const nextState: CacheComponentState = workInProgress.memoizedState;

    // Compare the new parent cache to the previous to see detect there was
    // a refresh.
    if (prevState.parent !== parentCache) {
      // Refresh in parent. Update the parent.
      const derivedState: CacheComponentState = {
        parent: parentCache,
        cache: parentCache,
      };

      // Copied from getDerivedStateFromProps implementation. Once the update
      // queue is empty, persist the derived state onto the base state.
      workInProgress.memoizedState = derivedState;
      if (workInProgress.lanes === NoLanes) {
        const updateQueue: UpdateQueue<any> = (workInProgress.updateQueue: any);
        workInProgress.memoizedState = updateQueue.baseState = derivedState;
      }

      pushCacheProvider(workInProgress, parentCache);
      // No need to propagate a context change because the refreshed parent
      // already did.
    } else {
      // The parent didn't refresh. Now check if this cache did.
      const nextCache = nextState.cache;
      pushCacheProvider(workInProgress, nextCache);
      if (nextCache !== prevState.cache) {
        // This cache refreshed. Propagate a context change.
        propagateContextChange(workInProgress, CacheContext, renderLanes);
      }
    }
  }