Inject() must be called from an injection context such as a constructor in AngularFirestoreDoc after upgrading to Angular v19

auth.service.ts の38行目の呼び出しから開始し、NG0203 のスタックトレースを入口として、AngularFirestore.doc を経由して angular-fire-compat-firestore.mjs まで追跡します。報告されている Angular v19 と @angular/fire v19 の依存関係バージョンを比較し、確立された再現手順または解決策があるか issue の議論を確認します。Injection Context のエラーが説明され、検証済みの互換性修正または maintainer が確認した次のステップが特定できれば完了です。

I recently upgraded all dependencies to Angular v19 (from v18). I was previously on Angular v18 where everything worked fine. However, now, my whole console is spammed with the following error:

ERROR RuntimeError: NG0203: inject() must be called from an injection context such as a constructor, a factory function, a field initializer, or a function used with `runInInjectionContext`. Find more at https://angular.dev/errors/NG0203
    at injectInjectorOnly (core.mjs:1104:11)
    at ɵɵinject (core.mjs:1114:40)
    at inject (core.mjs:1199:10)
    at <instance_members_initializer> (angular-fire-compat-firestore.mjs:93:14)
    at new AngularFirestoreDocument (angular-fire-compat-firestore.mjs:98:3)
    at _AngularFirestore.doc (angular-fire-compat-firestore.mjs:621:12)
    at auth.service.ts:38:14
    at switchMap.js:16:17
    at OperatorSubscriber2._this._next (OperatorSubscriber.js:14:9)
    at Subscriber2.next (Subscriber.js:32:12)

However, my auth service at line 38:14 only has the following code:
.doc<User>(`users/${user.uid}`)

The whole constructor looks like this (it is a angular service class)

  providedIn: 'root',
})
export class AuthService {
  isLoggedIn$: Observable<boolean>;
  /** User data of database */
  user$: Observable<User | null | undefined>;
  userRoles$: Observable<string[]>;
  userId: string | undefined = undefined;
  username: string | undefined = undefined;

  constructor(
    readonly firestore: AngularFirestore,
    readonly fireAuth: AngularFireAuth,
    readonly router: Router,
  ) {
    this.user$ = this.fireAuth.authState.pipe(
      switchMap((user) => {
        if (user) {
          this.userId = user.uid;
          return this.firestore
            .doc<User>(`users/${user.uid}`)
            .valueChanges()
            .pipe(
              map((userData) => {
                if (userData) {
                  this.username = userData.username; // Assign username
                }
                return userData;
              }),
            );
        } else {
          this.userId = undefined;
          this.username = undefined;
          return new Observable<User | null>((observer) => observer.next(null));
        }
      }),
    );

But I dont really know, why it does not work anymore in angular 19.

My package dependencies:

 "dependencies": {
    "@angular/animations": "^19.1.5",
    "@angular/cdk": "^19.1.3",
    "@angular/common": "^19.1.5",
    "@angular/compiler": "^19.1.5",
    "@angular/core": "^19.1.5",
    "@angular/fire": "^19.0.0",
    "@angular/forms": "^19.1.5",
    "@angular/material": "^19.1.3",
    "@angular/platform-browser": "^19.1.5",
    "@angular/platform-browser-dynamic": "^19.1.5",
    "@angular/router": "^19.1.5",
    "@fortawesome/angular-fontawesome": "^1.0.0",
    "@fortawesome/free-brands-svg-icons": "^6.7.1",
    "@fortawesome/free-regular-svg-icons": "^6.7.1",
    "@fortawesome/free-solid-svg-icons": "^6.7.1",
    "@ng-select/ng-select": "^14.2.2",
    "@ngx-translate/core": "^15.0.0",
    "@ngx-translate/http-loader": "^8.0.0",
    "angular-build-info": "^2.0.1",
    "canvas-confetti": "^1.9.3",
    "flowbite": "^2.5.2",
    "ng-recaptcha-2": "^15.0.2",
    "ngx-editor": "^18.0.0",
    "ngx-quill": "^27.0.0",
    "quill": "^2.0.3",
    "quill2-emoji": "^0.1.2",
    "rxjs": "~7.8.0",
    "tslib": "^2.8.1",
    "tw-elements": "^2.0.0",
    "zone.js": "^0.15.0"
  },

I also tried to set "preserveSymlinks": false, in angular.json however, the issue still persists.