Automatically reset forms after action finishes (#28804)

This updates the behavior of form actions to automatically reset the
form's uncontrolled inputs after the action finishes.

This is a frequent feature request for people using actions and it
aligns the behavior of client-side form submissions more closely with
MPA form submissions.

It has no impact on controlled form inputs. It's the same as if you
called `form.reset()` manually, except React handles the timing of when
the reset happens, which is tricky/impossible to get exactly right in
userspace.

The reset shouldn't happen until the UI has updated with the result of
the action. So, resetting inside the action is too early.

Resetting in `useEffect` is better, but it's later than ideal because
any effects that run before it will observe the state of the form before
it's been reset.

It needs to happen in the mutation phase of the transition. More
specifically, after all the DOM mutations caused by the transition have
been applied. That way the `defaultValue` of the inputs are updated
before the values are reset. The idea is that the `defaultValue`
represents the current, canonical value sent by the server.

Note: this change has no effect on form submissions that aren't
triggered by an action.

DiffTrain build for [41950d1](41950d1)

compiled/facebook-www/REVISION

@@ -1 +1 @@
-dc6a7e01e1d2fa5eb4974f9bb66e9e8fb40f6ef8
+41950d14a538aa7411b00b28bcd94ae95a45976e

compiled/facebook-www/ReactART-dev.classic.js

@@ -66,7 +66,7 @@ if (__DEV__) {
       return self;
     }
 
-    var ReactVersion = "19.0.0-www-classic-877fd74a";
+    var ReactVersion = "19.0.0-www-classic-5df29fbc";
 
     var LegacyRoot = 0;
     var ConcurrentRoot = 1;
@@ -586,6 +586,7 @@ if (__DEV__) {
     var ScheduleRetry = StoreConsistency;
     var ShouldSuspendCommit = Visibility;
     var DidDefer = ContentReset;
+    var FormReset = Snapshot;
     var LifecycleEffectMask =
       Passive$1 | Update | Callback | Ref | Snapshot | StoreConsistency; // Union of all commit flags (flags with the lifetime of a particular commit)
 
@@ -655,7 +656,8 @@ if (__DEV__) {
       ContentReset |
       Ref |
       Hydrating |
-      Visibility;
+      Visibility |
+      FormReset;
     var LayoutMask = Update | Callback | Ref | Visibility; // TODO: Split into PassiveMountMask and PassiveUnmountMask
 
     var PassiveMask = Passive$1 | Visibility | ChildDeletion; // Union of tags that don't get reset on clones.
@@ -9384,13 +9386,29 @@ if (__DEV__) {
       var _dispatcher$useState = dispatcher.useState(),
         maybeThenable = _dispatcher$useState[0];
 
+      var nextState;
+
       if (typeof maybeThenable.then === "function") {
         var thenable = maybeThenable;
-        return useThenable(thenable);
+        nextState = useThenable(thenable);
       } else {
         var status = maybeThenable;
-        return status;
+        nextState = status;
+      } // The "reset state" is an object. If it changes, that means something
+      // requested that we reset the form.
+
+      var _dispatcher$useState2 = dispatcher.useState(),
+        nextResetState = _dispatcher$useState2[0];
+
+      var prevResetState =
+        currentHook !== null ? currentHook.memoizedState : null;
+
+      if (prevResetState !== nextResetState) {
+        // Schedule a form reset
+        currentlyRenderingFiber$1.flags |= FormReset;
       }
+
+      return nextState;
     }
     function bailoutHooks(current, workInProgress, lanes) {
       workInProgress.updateQueue = current.updateQueue; // TODO: Don't need to reset the flags here, because they're reset in the
@@ -21259,7 +21277,7 @@ if (__DEV__) {
     // Allows us to avoid traversing the return path to find the nearest Offscreen ancestor.
 
     var offscreenSubtreeIsHidden = false;
-    var offscreenSubtreeWasHidden = false;
+    var offscreenSubtreeWasHidden = false; // Used to track if a form needs to be reset at the end of the mutation phase.
     var PossiblyWeakSet = typeof WeakSet === "function" ? WeakSet : Set;
     var nextEffect = null; // Used for Profiling builds to track updaters.
 
@@ -23591,6 +23609,19 @@ if (__DEV__) {
                 }
               }
             }
+
+            if (flags & FormReset) {
+              {
+                if (finishedWork.type !== "form") {
+                  // Paranoid coding. In case we accidentally start using the
+                  // FormReset bit for something else.
+                  error(
+                    "Unexpected host component type. Expected a form. This is a " +
+                      "bug in React."
+                  );
+                }
+              }
+            }
           }
 
           return;

compiled/facebook-www/ReactART-dev.modern.js

@@ -66,7 +66,7 @@ if (__DEV__) {
       return self;
     }
 
-    var ReactVersion = "19.0.0-www-modern-bf3441a6";
+    var ReactVersion = "19.0.0-www-modern-2b9608d3";
 
     var LegacyRoot = 0;
     var ConcurrentRoot = 1;
@@ -588,6 +588,7 @@ if (__DEV__) {
     var ScheduleRetry = StoreConsistency;
     var ShouldSuspendCommit = Visibility;
     var DidDefer = ContentReset;
+    var FormReset = Snapshot;
 
     var HostEffectMask =
       /*               */
@@ -655,7 +656,8 @@ if (__DEV__) {
       ContentReset |
       Ref |
       Hydrating |
-      Visibility;
+      Visibility |
+      FormReset;
     var LayoutMask = Update | Callback | Ref | Visibility; // TODO: Split into PassiveMountMask and PassiveUnmountMask
 
     var PassiveMask = Passive$1 | Visibility | ChildDeletion; // Union of tags that don't get reset on clones.
@@ -9135,13 +9137,29 @@ if (__DEV__) {
       var _dispatcher$useState = dispatcher.useState(),
         maybeThenable = _dispatcher$useState[0];
 
+      var nextState;
+
       if (typeof maybeThenable.then === "function") {
         var thenable = maybeThenable;
-        return useThenable(thenable);
+        nextState = useThenable(thenable);
       } else {
         var status = maybeThenable;
-        return status;
+        nextState = status;
+      } // The "reset state" is an object. If it changes, that means something
+      // requested that we reset the form.
+
+      var _dispatcher$useState2 = dispatcher.useState(),
+        nextResetState = _dispatcher$useState2[0];
+
+      var prevResetState =
+        currentHook !== null ? currentHook.memoizedState : null;
+
+      if (prevResetState !== nextResetState) {
+        // Schedule a form reset
+        currentlyRenderingFiber$1.flags |= FormReset;
       }
+
+      return nextState;
     }
     function bailoutHooks(current, workInProgress, lanes) {
       workInProgress.updateQueue = current.updateQueue; // TODO: Don't need to reset the flags here, because they're reset in the
@@ -20632,7 +20650,7 @@ if (__DEV__) {
     // Allows us to avoid traversing the return path to find the nearest Offscreen ancestor.
 
     var offscreenSubtreeIsHidden = false;
-    var offscreenSubtreeWasHidden = false;
+    var offscreenSubtreeWasHidden = false; // Used to track if a form needs to be reset at the end of the mutation phase.
     var PossiblyWeakSet = typeof WeakSet === "function" ? WeakSet : Set;
     var nextEffect = null; // Used for Profiling builds to track updaters.
 
@@ -22958,6 +22976,19 @@ if (__DEV__) {
                 }
               }
             }
+
+            if (flags & FormReset) {
+              {
+                if (finishedWork.type !== "form") {
+                  // Paranoid coding. In case we accidentally start using the
+                  // FormReset bit for something else.
+                  error(
+                    "Unexpected host component type. Expected a form. This is a " +
+                      "bug in React."
+                  );
+                }
+              }
+            }
           }
 
           return;

compiled/facebook-www/ReactART-prod.classic.js

@@ -2622,10 +2622,16 @@ function renderWithHooksAgain(workInProgress, Component, props, secondArg) {
   return children;
 }
 function TransitionAwareHostComponent() {
-  var maybeThenable = ReactSharedInternals.H.useState()[0];
-  return "function" === typeof maybeThenable.then
-    ? useThenable(maybeThenable)
-    : maybeThenable;
+  var dispatcher = ReactSharedInternals.H,
+    maybeThenable = dispatcher.useState()[0];
+  maybeThenable =
+    "function" === typeof maybeThenable.then
+      ? useThenable(maybeThenable)
+      : maybeThenable;
+  dispatcher = dispatcher.useState()[0];
+  (null !== currentHook ? currentHook.memoizedState : null) !== dispatcher &&
+    (currentlyRenderingFiber$1.flags |= 1024);
+  return maybeThenable;
 }
 function bailoutHooks(current, workInProgress, lanes) {
   workInProgress.updateQueue = current.updateQueue;
@@ -7855,7 +7861,7 @@ function recursivelyTraverseMutationEffects(root$jscomp$0, parentFiber) {
         captureCommitPhaseError(childToDelete, parentFiber, error);
       }
     }
-  if (parentFiber.subtreeFlags & 12854)
+  if (parentFiber.subtreeFlags & 13878)
     for (parentFiber = parentFiber.child; null !== parentFiber; )
       commitMutationEffectsOnFiber(parentFiber, root$jscomp$0),
         (parentFiber = parentFiber.sibling);
@@ -10599,7 +10605,7 @@ var slice = Array.prototype.slice,
       return null;
     },
     bundleType: 0,
-    version: "19.0.0-www-classic-f1bbc587",
+    version: "19.0.0-www-classic-52a8955f",
     rendererPackageName: "react-art"
   };
 var internals$jscomp$inline_1322 = {
@@ -10630,7 +10636,7 @@ var internals$jscomp$inline_1322 = {
   scheduleRoot: null,
   setRefreshHandler: null,
   getCurrentFiber: null,
-  reconcilerVersion: "19.0.0-www-classic-f1bbc587"
+  reconcilerVersion: "19.0.0-www-classic-52a8955f"
 };
 if ("undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__) {
   var hook$jscomp$inline_1323 = __REACT_DEVTOOLS_GLOBAL_HOOK__;

compiled/facebook-www/ReactART-prod.modern.js

@@ -2420,10 +2420,16 @@ function renderWithHooksAgain(workInProgress, Component, props, secondArg) {
   return children;
 }
 function TransitionAwareHostComponent() {
-  var maybeThenable = ReactSharedInternals.H.useState()[0];
-  return "function" === typeof maybeThenable.then
-    ? useThenable(maybeThenable)
-    : maybeThenable;
+  var dispatcher = ReactSharedInternals.H,
+    maybeThenable = dispatcher.useState()[0];
+  maybeThenable =
+    "function" === typeof maybeThenable.then
+      ? useThenable(maybeThenable)
+      : maybeThenable;
+  dispatcher = dispatcher.useState()[0];
+  (null !== currentHook ? currentHook.memoizedState : null) !== dispatcher &&
+    (currentlyRenderingFiber$1.flags |= 1024);
+  return maybeThenable;
 }
 function bailoutHooks(current, workInProgress, lanes) {
   workInProgress.updateQueue = current.updateQueue;
@@ -7410,7 +7416,7 @@ function recursivelyTraverseMutationEffects(root$jscomp$0, parentFiber) {
         captureCommitPhaseError(childToDelete, parentFiber, error);
       }
     }
-  if (parentFiber.subtreeFlags & 12854)
+  if (parentFiber.subtreeFlags & 13878)
     for (parentFiber = parentFiber.child; null !== parentFiber; )
       commitMutationEffectsOnFiber(parentFiber, root$jscomp$0),
         (parentFiber = parentFiber.sibling);
@@ -10078,7 +10084,7 @@ var slice = Array.prototype.slice,
       return null;
     },
     bundleType: 0,
-    version: "19.0.0-www-modern-4749dbb1",
+    version: "19.0.0-www-modern-e590ea90",
     rendererPackageName: "react-art"
   };
 var internals$jscomp$inline_1307 = {
@@ -10109,7 +10115,7 @@ var internals$jscomp$inline_1307 = {
   scheduleRoot: null,
   setRefreshHandler: null,
   getCurrentFiber: null,
-  reconcilerVersion: "19.0.0-www-modern-4749dbb1"
+  reconcilerVersion: "19.0.0-www-modern-e590ea90"
 };
 if ("undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__) {
   var hook$jscomp$inline_1308 = __REACT_DEVTOOLS_GLOBAL_HOOK__;