root.hydrate -> root.isDehydrated (#22420)

I think this naming is a bit clearer. It means the root is currently
showing server rendered content that needs to be hydrated.

A dehydrated root is conceptually the same as what we call dehydrated
Suspense boundary, so this makes the naming of the root align with the
naming of subtrees.

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

@@ -264,7 +264,7 @@ export function attemptToDispatchEvent(
         targetInst = null;
       } else if (tag === HostRoot) {
         const root: FiberRoot = nearestMounted.stateNode;
-        if (root.hydrate) {
+        if (root.isDehydrated) {
           // If this happens during a replay something went wrong and it might block
           // the whole system.
           return getContainerFromFiber(nearestMounted);

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

@@ -399,7 +399,7 @@ function attemptExplicitHydrationTarget(
         }
       } else if (tag === HostRoot) {
         const root: FiberRoot = nearestMounted.stateNode;
-        if (root.hydrate) {
+        if (root.isDehydrated) {
           queuedTarget.blockedOn = getContainerFromFiber(nearestMounted);
           // We don't currently have a way to increase the priority of
           // a root other than sync.

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

@@ -1295,7 +1295,7 @@ function updateHostRoot(current, workInProgress, renderLanes) {
     resetHydrationState();
     return bailoutOnAlreadyFinishedWork(current, workInProgress, renderLanes);
   }
-  if (root.hydrate && enterHydrationState(workInProgress)) {
+  if (root.isDehydrated && enterHydrationState(workInProgress)) {
     // If we don't have any current children this might be the first pass.
     // We always try to hydrate. If this isn't a hydration pass there won't
     // be any children to hydrate which is effectively the same thing as

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

@@ -1295,7 +1295,7 @@ function updateHostRoot(current, workInProgress, renderLanes) {
     resetHydrationState();
     return bailoutOnAlreadyFinishedWork(current, workInProgress, renderLanes);
   }
-  if (root.hydrate && enterHydrationState(workInProgress)) {
+  if (root.isDehydrated && enterHydrationState(workInProgress)) {
     // If we don't have any current children this might be the first pass.
     // We always try to hydrate. If this isn't a hydration pass there won't
     // be any children to hydrate which is effectively the same thing as

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

@@ -1827,9 +1827,9 @@ function commitWork(current: Fiber | null, finishedWork: Fiber): void {
       case HostRoot: {
         if (supportsHydration) {
           const root: FiberRoot = finishedWork.stateNode;
-          if (root.hydrate) {
+          if (root.isDehydrated) {
             // We've just hydrated. No need to hydrate again.
-            root.hydrate = false;
+            root.isDehydrated = false;
             commitHydratedContainer(root.containerInfo);
           }
         }
@@ -1933,9 +1933,9 @@ function commitWork(current: Fiber | null, finishedWork: Fiber): void {
     case HostRoot: {
       if (supportsHydration) {
         const root: FiberRoot = finishedWork.stateNode;
-        if (root.hydrate) {
+        if (root.isDehydrated) {
           // We've just hydrated. No need to hydrate again.
-          root.hydrate = false;
+          root.isDehydrated = false;
           commitHydratedContainer(root.containerInfo);
         }
       }

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

@@ -1827,9 +1827,9 @@ function commitWork(current: Fiber | null, finishedWork: Fiber): void {
       case HostRoot: {
         if (supportsHydration) {
           const root: FiberRoot = finishedWork.stateNode;
-          if (root.hydrate) {
+          if (root.isDehydrated) {
             // We've just hydrated. No need to hydrate again.
-            root.hydrate = false;
+            root.isDehydrated = false;
             commitHydratedContainer(root.containerInfo);
           }
         }
@@ -1933,9 +1933,9 @@ function commitWork(current: Fiber | null, finishedWork: Fiber): void {
     case HostRoot: {
       if (supportsHydration) {
         const root: FiberRoot = finishedWork.stateNode;
-        if (root.hydrate) {
+        if (root.isDehydrated) {
           // We've just hydrated. No need to hydrate again.
-          root.hydrate = false;
+          root.isDehydrated = false;
           commitHydratedContainer(root.containerInfo);
         }
       }

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

@@ -867,7 +867,7 @@ function completeWork(
           // If we hydrated, then we'll need to schedule an update for
           // the commit side-effects on the root.
           markUpdate(workInProgress);
-        } else if (!fiberRoot.hydrate) {
+        } else if (!fiberRoot.isDehydrated) {
           // Schedule an effect to clear this container at the start of the next commit.
           // This handles the case of React rendering into a container with previous children.
           // It's also safe to do for updates too, because current.child would only be null

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

@@ -867,7 +867,7 @@ function completeWork(
           // If we hydrated, then we'll need to schedule an update for
           // the commit side-effects on the root.
           markUpdate(workInProgress);
-        } else if (!fiberRoot.hydrate) {
+        } else if (!fiberRoot.isDehydrated) {
           // Schedule an effect to clear this container at the start of the next commit.
           // This handles the case of React rendering into a container with previous children.
           // It's also safe to do for updates too, because current.child would only be null

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

@@ -353,7 +353,7 @@ export function attemptSynchronousHydration(fiber: Fiber): void {
   switch (fiber.tag) {
     case HostRoot:
       const root: FiberRoot = fiber.stateNode;
-      if (root.hydrate) {
+      if (root.isDehydrated) {
         // Flush the first scheduled "update".
         const lanes = getHighestPriorityPendingLanes(root);
         flushRoot(root, lanes);

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

@@ -353,7 +353,7 @@ export function attemptSynchronousHydration(fiber: Fiber): void {
   switch (fiber.tag) {
     case HostRoot:
       const root: FiberRoot = fiber.stateNode;
-      if (root.hydrate) {
+      if (root.isDehydrated) {
         // Flush the first scheduled "update".
         const lanes = getHighestPriorityPendingLanes(root);
         flushRoot(root, lanes);

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

@@ -39,7 +39,7 @@ function FiberRootNode(containerInfo, tag, hydrate) {
   this.timeoutHandle = noTimeout;
   this.context = null;
   this.pendingContext = null;
-  this.hydrate = hydrate;
+  this.isDehydrated = hydrate;
   this.callbackNode = null;
   this.callbackPriority = NoLane;
   this.eventTimes = createLaneMap(NoLanes);

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

@@ -39,7 +39,7 @@ function FiberRootNode(containerInfo, tag, hydrate) {
   this.timeoutHandle = noTimeout;
   this.context = null;
   this.pendingContext = null;
-  this.hydrate = hydrate;
+  this.isDehydrated = hydrate;
   this.callbackNode = null;
   this.callbackPriority = NoLane;
   this.eventTimes = createLaneMap(NoLanes);

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

@@ -859,8 +859,8 @@ function recoverFromConcurrentError(root, errorRetryLanes) {
 
   // If an error occurred during hydration, discard server response and fall
   // back to client side render.
-  if (root.hydrate) {
-    root.hydrate = false;
+  if (root.isDehydrated) {
+    root.isDehydrated = false;
     if (__DEV__) {
       errorHydratingContainer(root.containerInfo);
     }
@@ -1076,8 +1076,8 @@ function performSyncWorkOnRoot(root) {
 
     // If an error occurred during hydration,
     // discard server response and fall back to client side render.
-    if (root.hydrate) {
-      root.hydrate = false;
+    if (root.isDehydrated) {
+      root.isDehydrated = false;
       if (__DEV__) {
         errorHydratingContainer(root.containerInfo);
       }

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

@@ -859,8 +859,8 @@ function recoverFromConcurrentError(root, errorRetryLanes) {
 
   // If an error occurred during hydration, discard server response and fall
   // back to client side render.
-  if (root.hydrate) {
-    root.hydrate = false;
+  if (root.isDehydrated) {
+    root.isDehydrated = false;
     if (__DEV__) {
       errorHydratingContainer(root.containerInfo);
     }
@@ -1076,8 +1076,8 @@ function performSyncWorkOnRoot(root) {
 
     // If an error occurred during hydration,
     // discard server response and fall back to client side render.
-    if (root.hydrate) {
-      root.hydrate = false;
+    if (root.isDehydrated) {
+      root.isDehydrated = false;
       if (__DEV__) {
         errorHydratingContainer(root.containerInfo);
       }

packages/react-reconciler/src/ReactInternalTypes.js

@@ -212,7 +212,7 @@ type BaseFiberRootProperties = {|
   context: Object | null,
   pendingContext: Object | null,
   // Determines if we should attempt to hydrate on the initial mount
-  +hydrate: boolean,
+  +isDehydrated: boolean,
 
   // Used by useMutableSource hook to avoid tearing during hydration.
   mutableSourceEagerHydrationData?: Array<