fix(number-input): preserve value on Enter with useActionState (#33667)

packages/react-dom-bindings/src/client/ReactDOMInput.js

@@ -474,13 +474,18 @@ export function setDefaultValue(
   type: ?string,
   value: ToStringValue,
 ) {
+  const stringValue = toString(value);
   if (
     // Focused number inputs synchronize on blur. See ChangeEventPlugin.js
+    // However, if the defaultValue has actually changed, we need to update it
+    // even for focused number inputs to ensure the visual value is properly updated
+    // after form actions complete.
     type !== 'number' ||
-    getActiveElement(node.ownerDocument) !== node
+    getActiveElement(node.ownerDocument) !== node ||
+    node.defaultValue !== stringValue
   ) {
-    if (node.defaultValue !== toString(value)) {
-      node.defaultValue = toString(value);
+    if (node.defaultValue !== stringValue) {
+      node.defaultValue = stringValue;
     }
   }
 }

packages/react-dom/src/__tests__/ReactDOMInput-test.js

@@ -3109,4 +3109,51 @@ describe('ReactDOMInput', () => {
     expect(log).toEqual(['']);
     expect(node.value).toBe('a');
   });
+
+  it('should update defaultValue for focused number inputs when value changes', async () => {
+    // This test reproduces the issue described in:
+    // https://github.com/facebook/react/issues/33667
+    // Bug: input type number ignores defaultValue after clicking Enter when used with useActionState
+
+    const TestComponent = () => {
+      const [state, setState] = React.useState({ value: '123' });
+
+      return (
+        <div>
+          <input 
+            type="number" 
+            defaultValue={state.value}
+            onKeyDown={(e) => {
+              if (e.key === 'Enter') {
+                // Simulate form action completion that updates state
+                setState({ value: '456' });
+              }
+            }}
+          />
+        </div>
+      );
+    };
+
+    await act(() => {
+      root.render(<TestComponent />);
+    });
+
+    const node = container.firstChild;
+    expect(node.defaultValue).toBe('123');
+    expect(node.value).toBe('123');
+
+    // Focus the input and type something
+    node.focus();
+    setUntrackedValue.call(node, '789');
+    dispatchEventOnNode(node, 'input');
+
+    // Simulate pressing Enter (which would trigger a form action)
+    const enterEvent = new KeyboardEvent('keydown', { key: 'Enter' });
+    node.dispatchEvent(enterEvent);
+
+    // The defaultValue should be updated even though the input is focused
+    expect(node.defaultValue).toBe('456');
+    // The visual value should also be updated
+    expect(node.value).toBe('456');
+  });
 });