fix(forms): memoize deepSignal value

leonsenft · leonsenft · commit dbbe15a9c86f · 2025-08-05T13:32:05.000-07:00
Test that submission errors are cleared from their corresponding field
when its value is changed. Submission errors should not be cleared from
fields whose values remain unchanged. This behavior relies on fields
memoizing their value, which `deepSignal()` now does.
diff --git a/packages/forms/experimental/src/util/deep_signal.ts b/packages/forms/experimental/src/util/deep_signal.ts
@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import {Signal, untracked, WritableSignal} from '@angular/core';
+import {computed, Signal, untracked, WritableSignal} from '@angular/core';
 import {SIGNAL} from '@angular/core/primitives/signals';
 import {isArray} from './type_guards';
 
@@ -22,9 +22,8 @@ export function deepSignal<S, K extends keyof S>(
   source: WritableSignal<S>,
   prop: Signal<K>,
 ): WritableSignal<S[K]> {
-  const read: WritableSignal<S[K]> = (() => {
-    return source()[prop()];
-  }) as WritableSignal<S[K]>;
+  // Memoize the property.
+  const read = computed(() => source()[prop()]) as WritableSignal<S[K]>;
 
   read[SIGNAL] = source[SIGNAL];
   read.set = (value: S[K]) => {
diff --git a/packages/forms/experimental/test/node/submit.spec.ts b/packages/forms/experimental/test/node/submit.spec.ts
@@ -199,6 +199,26 @@ describe('submit', () => {
     await expectAsync(submitPromise).toBeRejectedWith(error);
     expect(f().submitting()).toBe(false);
   });
+
+  it('errors are cleared on edit', async () => {
+    const data = signal({first: '', last: ''});
+    const f = form(data, {injector: TestBed.inject(Injector)});
+
+    await submit(f, async (form) => {
+      return [
+        ValidationError.custom({kind: 'submit', field: f.first}),
+        ValidationError.custom({kind: 'submit', field: f.last}),
+      ];
+    });
+
+    expect(f.first().errors()).toEqual([ValidationError.custom({kind: 'submit'})]);
+    expect(f.last().errors()).toEqual([ValidationError.custom({kind: 'submit'})]);
+
+    f.first().value.set('Hello');
+
+    expect(f.first().errors()).toEqual([]);
+    expect(f.last().errors()).toEqual([ValidationError.custom({kind: 'submit'})]);
+  });
 });
 
 /**
