Fork ReactFiberLane

This wasn't forked previously because Lane and associated types are
opaque, and they leak into non-reconciler packages. So forking the type
would also require forking all those other packages.

But I really want to use the reconciler fork infra for lanes changes.
So I made them no longer opaque.

Another possible solution would be to add separate `new` and `old`
fields to the Fiber type, like I did when migrating from expiration
times. But that seems so excessive. This seems fine.

But we should still treat them like they're opaque and only do lanes
manipulation in the ReactFiberLane module. At least until the model
stabilizes more. We'll just need to enforce this with discipline
instead of with the type system.

packages/react-dom/src/events/ReactDOMEventListener.js

@@ -41,6 +41,7 @@ import {getClosestInstanceFromNode} from '../client/ReactDOMComponentTree';
 import {
   enableLegacyFBSupport,
   decoupleUpdatePriorityFromScheduler,
+  enableNewReconciler,
 } from 'shared/ReactFeatureFlags';
 import {
   UserBlockingEvent,
@@ -53,11 +54,27 @@ import {
   flushDiscreteUpdatesIfNeeded,
   discreteUpdates,
 } from './ReactDOMUpdateBatching';
+
+import {
+  InputContinuousLanePriority as InputContinuousLanePriority_old,
+  getCurrentUpdateLanePriority as getCurrentUpdateLanePriority_old,
+  setCurrentUpdateLanePriority as setCurrentUpdateLanePriority_old,
+} from 'react-reconciler/src/ReactFiberLane.old';
 import {
-  InputContinuousLanePriority,
-  getCurrentUpdateLanePriority,
-  setCurrentUpdateLanePriority,
-} from 'react-reconciler/src/ReactFiberLane';
+  InputContinuousLanePriority as InputContinuousLanePriority_new,
+  getCurrentUpdateLanePriority as getCurrentUpdateLanePriority_new,
+  setCurrentUpdateLanePriority as setCurrentUpdateLanePriority_new,
+} from 'react-reconciler/src/ReactFiberLane.new';
+
+const InputContinuousLanePriority = enableNewReconciler
+  ? InputContinuousLanePriority_new
+  : InputContinuousLanePriority_old;
+const getCurrentUpdateLanePriority = enableNewReconciler
+  ? getCurrentUpdateLanePriority_new
+  : getCurrentUpdateLanePriority_old;
+const setCurrentUpdateLanePriority = enableNewReconciler
+  ? setCurrentUpdateLanePriority_new
+  : setCurrentUpdateLanePriority_old;
 
 const {
   unstable_UserBlockingPriority: UserBlockingPriority,

packages/react-dom/src/events/ReactDOMEventReplaying.js

@@ -12,7 +12,7 @@ import type {Container, SuspenseInstance} from '../client/ReactDOMHostConfig';
 import type {DOMEventName} from '../events/DOMEventNames';
 import type {EventSystemFlags} from './EventSystemFlags';
 import type {FiberRoot} from 'react-reconciler/src/ReactInternalTypes';
-import type {LanePriority} from 'react-reconciler/src/ReactFiberLane';
+import type {LanePriority} from 'react-reconciler/src/ReactFiberLane.old';
 
 import {enableSelectiveHydration} from 'shared/ReactFeatureFlags';
 import {

packages/react-reconciler/src/DebugTracing.js

@@ -7,7 +7,7 @@
  * @flow
  */
 
-import type {Lane, Lanes} from './ReactFiberLane';
+import type {Lane, Lanes} from './ReactFiberLane.old';
 import type {Wakeable} from 'shared/ReactTypes';
 
 import {enableDebugTracing} from 'shared/ReactFeatureFlags';

packages/react-reconciler/src/ReactChildFiber.new.js

@@ -10,7 +10,7 @@
 import type {ReactElement} from 'shared/ReactElementType';
 import type {ReactPortal} from 'shared/ReactTypes';
 import type {Fiber} from './ReactInternalTypes';
-import type {Lanes} from './ReactFiberLane';
+import type {Lanes} from './ReactFiberLane.new';
 
 import getComponentName from 'shared/getComponentName';
 import {Placement, Deletion} from './ReactFiberFlags';

packages/react-reconciler/src/ReactChildFiber.old.js

@@ -10,7 +10,7 @@
 import type {ReactElement} from 'shared/ReactElementType';
 import type {ReactPortal} from 'shared/ReactTypes';
 import type {Fiber} from './ReactInternalTypes';
-import type {Lanes} from './ReactFiberLane';
+import type {Lanes} from './ReactFiberLane.old';
 
 import getComponentName from 'shared/getComponentName';
 import {Placement, Deletion} from './ReactFiberFlags';

packages/react-reconciler/src/ReactFiber.new.js

@@ -18,7 +18,7 @@ import type {Fiber} from './ReactInternalTypes';
 import type {RootTag} from './ReactRootTags';
 import type {WorkTag} from './ReactWorkTags';
 import type {TypeOfMode} from './ReactTypeOfMode';
-import type {Lanes} from './ReactFiberLane';
+import type {Lanes} from './ReactFiberLane.new';
 import type {SuspenseInstance} from './ReactFiberHostConfig';
 import type {OffscreenProps} from './ReactFiberOffscreenComponent';
 
@@ -63,7 +63,7 @@ import {
   resolveFunctionForHotReloading,
   resolveForwardRefForHotReloading,
 } from './ReactFiberHotReloading.new';
-import {NoLanes} from './ReactFiberLane';
+import {NoLanes} from './ReactFiberLane.new';
 import {
   NoMode,
   ConcurrentMode,

packages/react-reconciler/src/ReactFiber.old.js

@@ -18,7 +18,7 @@ import type {Fiber} from './ReactInternalTypes';
 import type {RootTag} from './ReactRootTags';
 import type {WorkTag} from './ReactWorkTags';
 import type {TypeOfMode} from './ReactTypeOfMode';
-import type {Lanes} from './ReactFiberLane';
+import type {Lanes} from './ReactFiberLane.old';
 import type {SuspenseInstance} from './ReactFiberHostConfig';
 import type {OffscreenProps} from './ReactFiberOffscreenComponent';
 
@@ -63,7 +63,7 @@ import {
   resolveFunctionForHotReloading,
   resolveForwardRefForHotReloading,
 } from './ReactFiberHotReloading.old';
-import {NoLanes} from './ReactFiberLane';
+import {NoLanes} from './ReactFiberLane.old';
 import {
   NoMode,
   ConcurrentMode,

packages/react-reconciler/src/ReactFiberBeginWork.new.js

@@ -11,7 +11,7 @@ import type {ReactProviderType, ReactContext} from 'shared/ReactTypes';
 import type {LazyComponent as LazyComponentType} from 'react/src/ReactLazy';
 import type {Fiber} from './ReactInternalTypes';
 import type {FiberRoot} from './ReactInternalTypes';
-import type {Lanes, Lane} from './ReactFiberLane';
+import type {Lanes, Lane} from './ReactFiberLane.new';
 import type {MutableSource} from 'shared/ReactTypes';
 import type {
   SuspenseState,
@@ -113,7 +113,7 @@ import {
   removeLanes,
   mergeLanes,
   getBumpedLaneForHydration,
-} from './ReactFiberLane';
+} from './ReactFiberLane.new';
 import {
   ConcurrentMode,
   NoMode,

packages/react-reconciler/src/ReactFiberBeginWork.old.js

@@ -11,7 +11,7 @@ import type {ReactProviderType, ReactContext} from 'shared/ReactTypes';
 import type {LazyComponent as LazyComponentType} from 'react/src/ReactLazy';
 import type {Fiber} from './ReactInternalTypes';
 import type {FiberRoot} from './ReactInternalTypes';
-import type {Lanes, Lane} from './ReactFiberLane';
+import type {Lanes, Lane} from './ReactFiberLane.old';
 import type {MutableSource} from 'shared/ReactTypes';
 import type {
   SuspenseState,
@@ -113,7 +113,7 @@ import {
   removeLanes,
   mergeLanes,
   getBumpedLaneForHydration,
-} from './ReactFiberLane';
+} from './ReactFiberLane.old';
 import {
   ConcurrentMode,
   NoMode,

packages/react-reconciler/src/ReactFiberClassComponent.new.js

@@ -8,7 +8,7 @@
  */
 
 import type {Fiber} from './ReactInternalTypes';
-import type {Lanes} from './ReactFiberLane';
+import type {Lanes} from './ReactFiberLane.new';
 import type {UpdateQueue} from './ReactUpdateQueue.new';
 
 import * as React from 'react';
@@ -42,7 +42,7 @@ import {
   initializeUpdateQueue,
   cloneUpdateQueue,
 } from './ReactUpdateQueue.new';
-import {NoLanes} from './ReactFiberLane';
+import {NoLanes} from './ReactFiberLane.new';
 import {
   cacheContext,
   getMaskedContext,

packages/react-reconciler/src/ReactFiberClassComponent.old.js

@@ -8,7 +8,7 @@
  */
 
 import type {Fiber} from './ReactInternalTypes';
-import type {Lanes} from './ReactFiberLane';
+import type {Lanes} from './ReactFiberLane.old';
 import type {UpdateQueue} from './ReactUpdateQueue.old';
 
 import * as React from 'react';
@@ -42,7 +42,7 @@ import {
   initializeUpdateQueue,
   cloneUpdateQueue,
 } from './ReactUpdateQueue.old';
-import {NoLanes} from './ReactFiberLane';
+import {NoLanes} from './ReactFiberLane.old';
 import {
   cacheContext,
   getMaskedContext,

packages/react-reconciler/src/ReactFiberCommitWork.new.js

@@ -17,7 +17,7 @@ import type {
 } from './ReactFiberHostConfig';
 import type {Fiber} from './ReactInternalTypes';
 import type {FiberRoot} from './ReactInternalTypes';
-import type {Lanes} from './ReactFiberLane';
+import type {Lanes} from './ReactFiberLane.new';
 import type {SuspenseState} from './ReactFiberSuspenseComponent.new';
 import type {UpdateQueue} from './ReactUpdateQueue.new';
 import type {FunctionComponentUpdateQueue} from './ReactFiberHooks.new';

packages/react-reconciler/src/ReactFiberCommitWork.old.js

@@ -17,7 +17,7 @@ import type {
 } from './ReactFiberHostConfig';
 import type {Fiber} from './ReactInternalTypes';
 import type {FiberRoot} from './ReactInternalTypes';
-import type {Lanes} from './ReactFiberLane';
+import type {Lanes} from './ReactFiberLane.old';
 import type {SuspenseState} from './ReactFiberSuspenseComponent.old';
 import type {UpdateQueue} from './ReactUpdateQueue.old';
 import type {FunctionComponentUpdateQueue} from './ReactFiberHooks.old';

packages/react-reconciler/src/ReactFiberCompleteWork.new.js

@@ -8,7 +8,7 @@
  */
 
 import type {Fiber} from './ReactInternalTypes';
-import type {Lanes} from './ReactFiberLane';
+import type {Lanes} from './ReactFiberLane.new';
 import type {
   ReactFundamentalComponentInstance,
   ReactScopeInstance,
@@ -130,7 +130,7 @@ import {
   getRenderTargetTime,
 } from './ReactFiberWorkLoop.new';
 import {createFundamentalStateInstance} from './ReactFiberFundamental.new';
-import {OffscreenLane, SomeRetryLane} from './ReactFiberLane';
+import {OffscreenLane, SomeRetryLane} from './ReactFiberLane.new';
 import {resetChildFibers} from './ReactChildFiber.new';
 import {createScopeInstance} from './ReactFiberScope.new';
 import {transferActualDuration} from './ReactProfilerTimer.new';

packages/react-reconciler/src/ReactFiberCompleteWork.old.js

@@ -8,7 +8,7 @@
  */
 
 import type {Fiber} from './ReactInternalTypes';
-import type {Lanes} from './ReactFiberLane';
+import type {Lanes} from './ReactFiberLane.old';
 import type {
   ReactFundamentalComponentInstance,
   ReactScopeInstance,
@@ -130,7 +130,7 @@ import {
   getRenderTargetTime,
 } from './ReactFiberWorkLoop.old';
 import {createFundamentalStateInstance} from './ReactFiberFundamental.old';
-import {OffscreenLane, SomeRetryLane} from './ReactFiberLane';
+import {OffscreenLane, SomeRetryLane} from './ReactFiberLane.old';
 import {resetChildFibers} from './ReactChildFiber.old';
 import {createScopeInstance} from './ReactFiberScope.old';
 import {transferActualDuration} from './ReactProfilerTimer.old';

packages/react-reconciler/src/ReactFiberHooks.new.js

@@ -14,7 +14,7 @@ import type {
   ReactContext,
 } from 'shared/ReactTypes';
 import type {Fiber, Dispatcher, HookType} from './ReactInternalTypes';
-import type {Lanes, Lane} from './ReactFiberLane';
+import type {Lanes, Lane} from './ReactFiberLane.new';
 import type {HookFlags} from './ReactHookEffectTags';
 import type {ReactPriorityLevel} from './ReactInternalTypes';
 import type {FiberRoot} from './ReactInternalTypes';
@@ -44,7 +44,7 @@ import {
   setCurrentUpdateLanePriority,
   higherLanePriority,
   DefaultLanePriority,
-} from './ReactFiberLane';
+} from './ReactFiberLane.new';
 import {readContext} from './ReactFiberNewContext.new';
 import {
   Update as UpdateEffect,

packages/react-reconciler/src/ReactFiberHooks.old.js

@@ -14,7 +14,7 @@ import type {
   ReactContext,
 } from 'shared/ReactTypes';
 import type {Fiber, Dispatcher, HookType} from './ReactInternalTypes';
-import type {Lanes, Lane} from './ReactFiberLane';
+import type {Lanes, Lane} from './ReactFiberLane.old';
 import type {HookFlags} from './ReactHookEffectTags';
 import type {ReactPriorityLevel} from './ReactInternalTypes';
 import type {FiberRoot} from './ReactInternalTypes';
@@ -44,7 +44,7 @@ import {
   setCurrentUpdateLanePriority,
   higherLanePriority,
   DefaultLanePriority,
-} from './ReactFiberLane';
+} from './ReactFiberLane.old';
 import {readContext} from './ReactFiberNewContext.old';
 import {
   Update as UpdateEffect,

packages/react-reconciler/src/ReactFiberHotReloading.new.js

@@ -20,7 +20,7 @@ import {
 } from './ReactFiberWorkLoop.new';
 import {updateContainer} from './ReactFiberReconciler.new';
 import {emptyContextObject} from './ReactFiberContext.new';
-import {SyncLane, NoTimestamp} from './ReactFiberLane';
+import {SyncLane, NoTimestamp} from './ReactFiberLane.new';
 import {
   ClassComponent,
   FunctionComponent,

packages/react-reconciler/src/ReactFiberHotReloading.old.js

@@ -20,7 +20,7 @@ import {
 } from './ReactFiberWorkLoop.old';
 import {updateContainer} from './ReactFiberReconciler.old';
 import {emptyContextObject} from './ReactFiberContext.old';
-import {SyncLane, NoTimestamp} from './ReactFiberLane';
+import {SyncLane, NoTimestamp} from './ReactFiberLane.old';
 import {
   ClassComponent,
   FunctionComponent,

packages/react-reconciler/src/ReactFiberHydrationContext.new.js

@@ -55,7 +55,7 @@ import {
   didNotFindHydratableSuspenseInstance,
 } from './ReactFiberHostConfig';
 import {enableSuspenseServerRenderer} from 'shared/ReactFeatureFlags';
-import {OffscreenLane} from './ReactFiberLane';
+import {OffscreenLane} from './ReactFiberLane.new';
 
 // The deepest Fiber on the stack involved in a hydration context.
 // This may have been an insertion or a hydration.

packages/react-reconciler/src/ReactFiberHydrationContext.old.js

@@ -55,7 +55,7 @@ import {
   didNotFindHydratableSuspenseInstance,
 } from './ReactFiberHostConfig';
 import {enableSuspenseServerRenderer} from 'shared/ReactFeatureFlags';
-import {OffscreenLane} from './ReactFiberLane';
+import {OffscreenLane} from './ReactFiberLane.old';
 
 // The deepest Fiber on the stack involved in a hydration context.
 // This may have been an insertion or a hydration.

packages/react-reconciler/src/ReactFiberLane.js → packages/react-reconciler/src/ReactFiberLane.new.js

@@ -9,7 +9,9 @@
 
 import type {FiberRoot, ReactPriorityLevel} from './ReactInternalTypes';
 
-export opaque type LanePriority =
+// TODO: Ideally these types would be opaque but that doesn't work well with
+// our reconciler fork infra, since these leak into non-reconciler packages.
+export type LanePriority =
   | 0
   | 1
   | 2
@@ -28,9 +30,10 @@ export opaque type LanePriority =
   | 15
   | 16
   | 17;
-export opaque type Lanes = number;
-export opaque type Lane = number;
-export opaque type LaneMap<T> = Array<T>;
+
+export type Lanes = number;
+export type Lane = number;
+export type LaneMap<T> = Array<T>;
 
 import invariant from 'shared/invariant';