fix(signals): run onDestroy outside of injection context (#4200)

Author: rainerhahnekamp

modules/signals/spec/signal-store.spec.ts

@@ -268,6 +268,8 @@ describe('signalStore', () => {
       expect(message).toBe('onDestroy');
     });
 
+    // FIX: injection context will be provided for `onDestroy` in a separate PR
+    // see https://github.com/ngrx/platform/pull/4196#issuecomment-1875228588
     it('executes hooks in injection context', () => {
       const messages: string[] = [];
       const TOKEN = new InjectionToken('TOKEN', {
@@ -281,7 +283,7 @@ describe('signalStore', () => {
             messages.push('onInit');
           },
           onDestroy() {
-            inject(TOKEN);
+            // inject(TOKEN);
             messages.push('onDestroy');
           },
         })
@@ -293,6 +295,22 @@ describe('signalStore', () => {
       destroy();
       expect(messages).toEqual(['onInit', 'onDestroy']);
     });
+
+    it('succeeds with onDestroy and providedIn: root', () => {
+      const messages: string[] = [];
+      const Store = signalStore(
+        { providedIn: 'root' },
+        withHooks({
+          onDestroy() {
+            messages.push('ending...');
+          },
+        })
+      );
+      TestBed.inject(Store);
+      TestBed.resetTestEnvironment();
+
+      expect(messages).toEqual(['ending...']);
+    });
   });
 
   describe('composition', () => {

modules/signals/src/signal-store.ts

@@ -1,21 +1,13 @@
-import {
-  DestroyRef,
-  inject,
-  Injectable,
-  Injector,
-  runInInjectionContext,
-  signal,
-  Type,
-} from '@angular/core';
+import { DestroyRef, inject, Injectable, signal, Type } from '@angular/core';
 import { STATE_SIGNAL, StateSignal } from './state-signal';
 import {
   EmptyFeatureResult,
   InnerSignalStore,
   MergeFeatureResults,
-  SignalStoreProps,
   SignalStoreConfig,
   SignalStoreFeature,
   SignalStoreFeatureResult,
+  SignalStoreProps,
 } from './signal-store-models';
 import { Prettify } from './ts-helpers';
 
@@ -325,16 +317,14 @@ export function signalStore(
         (this as any)[key] = props[key];
       }
 
-      if (hooks.onInit) {
-        hooks.onInit();
-      }
+      const { onInit, onDestroy } = hooks;
 
-      if (hooks.onDestroy) {
-        const injector = inject(Injector);
+      if (onInit) {
+        onInit();
+      }
 
-        inject(DestroyRef).onDestroy(() => {
-          runInInjectionContext(injector, hooks.onDestroy!);
-        });
+      if (onDestroy) {
+        inject(DestroyRef).onDestroy(onDestroy);
       }
     }
   }