Refactor legacy update queue

Refactors legacy update queue to incoporate rebasing fix. Uses nearly
the same approach as the hook update queue but has to handle a few
other cases.

Author: acdlite

packages/create-subscription/src/__tests__/createSubscription-test.internal.js

@@ -160,7 +160,7 @@ describe('createSubscription', () => {
 
     it('should still work if unsubscription is managed incorrectly', async () => {
       const Subscription = createSubscription({
-        getCurrentValue: source => undefined,
+        getCurrentValue: source => source.value,
         subscribe: (source, callback) => {
           source.then(callback);
           // (Can't unsubscribe from a Promise)
@@ -174,8 +174,18 @@ describe('createSubscription', () => {
       }
 
       let resolveA, resolveB;
-      const promiseA = new Promise(resolve => (resolveA = resolve));
-      const promiseB = new Promise(resolve => (resolveB = resolve));
+      const promiseA = new Promise(resolve => {
+        resolveA = v => {
+          resolve(v);
+          promiseA.value = v;
+        };
+      });
+      const promiseB = new Promise(resolve => {
+        resolveB = v => {
+          resolve(v);
+          promiseB.value = v;
+        };
+      });
 
       // Subscribe first to Promise A then Promise B
       ReactNoop.render(<Subscription source={promiseA}>{render}</Subscription>);

packages/react-noop-renderer/src/createReactNoop.js

@@ -1142,20 +1142,33 @@ function createReactNoop(reconciler: Function, useMutation: boolean) {
 
       function logUpdateQueue(updateQueue: UpdateQueue<mixed>, depth) {
         log('  '.repeat(depth + 1) + 'QUEUED UPDATES');
-        const firstUpdate = updateQueue.firstUpdate;
-        if (!firstUpdate) {
+        const last = updateQueue.baseQueue;
+        if (last === null) {
           return;
         }
+        const first = last.next;
+        let update = first;
+        if (update !== null) {
+          do {
+            log(
+              '  '.repeat(depth + 1) + '~',
+              '[' + update.expirationTime + ']',
+            );
+          } while (update !== null && update !== first);
+        }
 
-        log(
-          '  '.repeat(depth + 1) + '~',
-          '[' + firstUpdate.expirationTime + ']',
-        );
-        while (firstUpdate.next) {
-          log(
-            '  '.repeat(depth + 1) + '~',
-            '[' + firstUpdate.expirationTime + ']',
-          );
+        const lastPending = updateQueue.shared.pending;
+        if (lastPending !== null) {
+          const firstPending = lastPending.next;
+          let pendingUpdate = firstPending;
+          if (pendingUpdate !== null) {
+            do {
+              log(
+                '  '.repeat(depth + 1) + '~',
+                '[' + pendingUpdate.expirationTime + ']',
+              );
+            } while (pendingUpdate !== null && pendingUpdate !== firstPending);
+          }
         }
       }
 

packages/react-reconciler/src/ReactFiberHooks.js

@@ -1299,11 +1299,7 @@ function dispatchAction<S, A>(
       // This is the first update. Create a circular list.
       update.next = update;
     } else {
-      const first = pending.next;
-      if (first !== null) {
-        // Still circular.
-        update.next = first;
-      }
+      update.next = pending.next;
       pending.next = update;
     }
     queue.pending = update;

packages/react-reconciler/src/ReactFiberWorkLoop.js

@@ -2858,7 +2858,7 @@ export function checkForWrongSuspensePriorityInDEV(sourceFiber: Fiber) {
               // has triggered any high priority updates
               const updateQueue = current.updateQueue;
               if (updateQueue !== null) {
-                let update = updateQueue.firstUpdate;
+                let update = updateQueue.baseQueue;
                 while (update !== null) {
                   const priorityLevel = update.priority;
                   if (