fix(cli): Fix a regression where Gateway authentication is rejected with Invalid auth method selected. when GOOGLE_GEMINI_BASE_URL is configured.

[shaurya-cd]

Summary

Fix a regression where Gateway authentication is rejected with Invalid auth method selected. when GOOGLE_GEMINI_BASE_URL is configured.

getAuthTypeFromEnv() returns AuthType.GATEWAY when GOOGLE_GEMINI_BASE_URL is set, but validateAuthMethod() did not handle AuthType.GATEWAY, causing validation to fail before requests were sent.

Details

Adds validation support for AuthType.GATEWAY in validateAuthMethod().

Gateway authentication now:

• succeeds when GOOGLE_GEMINI_BASE_URL is configured
• returns a clear validation error when GOOGLE_GEMINI_BASE_URL is missing

Also adds regression tests covering successful and failing Gateway validation scenarios.

Related Issues

Fixes #27550

How to Validate

1. Run the auth validation tests:

npx vitest packages/cli/src/config/auth.test.ts

Expected result:

10 passed

2. Run the non-interactive auth tests:

npx vitest packages/cli/src/validateNonInterActiveAuth.test.ts

Expected result:

17 passed

3. Build the project:

npm run build

Expected result:

Build is up-to-date.
Successfully copied files.

4. Reproduce the original issue:

GOOGLE_API_KEY=proxy-token
GOOGLE_GEMINI_BASE_URL=http://127.0.0.1:8080
GOOGLE_GENAI_USE_VERTEXAI=false

Run:

gemini --prompt "Hello world" --yolo

Before this change:

Invalid auth method selected.

After this change:

Authentication validation succeeds and execution proceeds to the network layer (e.g. fetch failed if no proxy is listening on the configured endpoint).

Pre-Merge Checklist

• Updated relevant documentation and README (not needed)

• Added/updated tests

• Noted breaking changes (none)

• Validated on required platforms/methods:

  • MacOS

    • npm run
    • npx
    • Docker
    • Podman
    • Seatbelt

  • Windows

    • npm run
    • npx
    • Docker

  • Linux

    • npm run
    • npx
    • Docker

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a regression in the CLI's authentication flow where users were incorrectly receiving an 'Invalid auth method selected' error when attempting to use Gateway authentication. By explicitly adding validation support for the Gateway auth type and ensuring the required base URL environment variable is present, the fix restores expected functionality for Gemini integrations.

Highlights

• Gateway Authentication Fix: Updated the authentication validation logic to correctly recognize and support AuthType.GATEWAY, resolving a regression that blocked requests when GOOGLE_GEMINI_BASE_URL was configured.
• Validation Logic: Added a mandatory check for the GOOGLE_GEMINI_BASE_URL environment variable when using Gateway authentication to ensure proper configuration.
• Regression Testing: Introduced new test cases in the authentication suite to verify both successful Gateway authentication and error handling for missing configuration.

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[gemini-code-assist]

Code Review

This pull request introduces validation logic and tests for the GATEWAY authentication method, ensuring that the GOOGLE_GEMINI_BASE_URL environment variable is configured. The feedback notes that, according to the repository style guide, an empty string should be used instead of undefined to unset environment variables in tests.