Weird interaction between patchState in effect and watchState

[rmeyergh]

Which @ngrx/* package(s) are the source of the bug?

signals

Minimal reproduction of the bug/regression with instructions

When the "trigger" button in the component below is clicked, the watcher will trigger as seen in the console output. It will not happen as soon as patchState inside the effect or triggerService.trigger() inside the watcher are wrapped with untracked() but I don't think that should be necessary. If it is it should at least be mentioned in the documentation. I have no explanation why that happens.

import { Component, effect, inject, Injectable, signal } from '@angular/core';
import { patchState, signalStore, watchState, withHooks, withState } from '@ngrx/signals';

@Injectable({ providedIn: 'root' })
export class TriggerService {
  trigger = signal(0);
}

const MyStore = signalStore(
  withState({}),
  withHooks({
    onInit(store, triggerService = inject(TriggerService)) {
      effect(() => {
        patchState(store, (state) => ({
          ...state,
        }));
      });

      watchState(store, () => {
        if (triggerService.trigger()) console.log('watcher triggered');
      });
    },
  }),
);

@Component({
  selector: 'app-root',
  providers: [MyStore],
  template: `<button (click)="trigger()">trigger</button>`,
})
export class App {
  private readonly triggerService = inject(TriggerService);
  private readonly store = inject(MyStore);

  trigger() {
    this.triggerService.trigger.update((count) => count + 1);
  }
}

Expected behavior

The watcher should not react to the signal when the button is clicked.

Versions of NgRx, Angular, Node, affected browser(s) and operating system(s)

NgRx: 21.1.0
Angular: 21.2.14
Node: 24.13.0
Browser: Chrome 148.0.7778.216
OS: macOs Tahoe 26.5.1

Other information

No response

I would be willing to submit a PR to fix this issue

• Yes
• No