Auth event v1 compat

[shettyvarun268]

relnote: none

Description

Adds V1Compat destructuring support to 2nd-Gen Firebase Authentication triggers (onUserCreated and onUserDeleted), bringing Auth to full feature and type parity with firestore, pubsub, storage, database, and remoteConfig.

Key changes:

• Lazy Getters via addV1Compat: Attaches user (returning event.data) and context (returning getV1AuthContext(event)) via non-enumerable, memoized getters with zero performance/allocation overhead for standard v2 callers.
• V1 Field Parity (getV1AuthContext): Maps legacy EventContext properties:
  • eventType: Translates v2 CloudEvent types to "providers/firebase.auth/eventTypes/user.create" and "user.delete".
  • resource: Sets service: "firebaseauth.googleapis.com" and normalizes name by stripping //identitytoolkit.googleapis.com/.
  • params: {}, eventId, timestamp.
• TypeScript Contravariance Overloads: Declares overloads for both (event: AuthEvent<User> & V1Compat<"user", User>) and (event: AuthEvent<User>) to ensure user test suites passing vanilla POJO CloudEvent mocks to .run() compile without type friction.
• Constants Extraction: Centralizes top-level constants (IDENTITY_TOOLKIT_SOURCE_PREFIX, FIREBASE_AUTH_SERVICE, USER_CREATED_EVENT, USER_DELETED_EVENT).

Scenarios Tested

• Unit Tests (spec/v2/providers/identity.spec.ts):
  • Verified v1-compatible getters (event.user and all fields of event.context).
  • Verified destructuring assignment syntax: onUserCreated(({ user, context }) => ...).
  • Verified backward compatibility for plain mock POJOs passed to .run().
  • Ran full test suite: 988 passing tests (npm test).
• Live GCP Deployment:
  • Deployed onUserCreated(({ user, context }) => ...) to test project varun-test-project-auth.
  • Triggered passwordless email link sign-up flow and verified in Cloud Run logs that user.uid, user.email, context.eventId, context.eventType, and context.resource were captured and logged correctly.

[gemini-code-assist]

Code Review

This pull request introduces v1-compatible getters (user and context) to the v2 onUserCreated and onUserDeleted Identity triggers, enabling developers to use v1-style destructuring. It also adds corresponding unit tests to verify this compatibility. A critical runtime issue was identified where calling the trigger's .run() method in unit tests with a vanilla mock event will crash if destructuring is used, because .run is not wrapped with addV1Compat. It is recommended to wrap func.run to apply the compatibility layer.

[shettyvarun268]

/gemini review

[gemini-code-assist]

Code Review

This pull request adds backward-compatible v1 getters (context and user) to the v2 Firebase Authentication triggers (onUserCreated and onUserDeleted) by wrapping the events using addV1Compat in both the main trigger execution and the .run() method. The feedback suggests adding a defensive check for the event parameter in func.run to prevent potential TypeErrors when developers call .run() with nullish values in unit tests.