fix(ui): surface sign-in-only auth errors

[swolfand]

What & why

• Fix AuthMode.SignIn failures remaining in Loading indefinitely.
• Preserve the sign-in-or-up fallback only for identifier-not-found and invitation-account-not-found errors.
• Surface all other API and unknown/network failures through AuthState.Error.
• Add regression coverage for API and unknown failures in sign-in-only mode.

The failure handler previously gated its entire body on withSignUp, so sign-in-only attempts never updated UI state after an error.

Linear: MOBILE-602

What to focus on

• The fallback condition in AuthStartViewModel.signIn and whether any additional errors should transfer into sign-up.

Screenshots / video

Manually verified with the workbench configured in sign-in-only mode: an invalid identifier surfaces an error instead of leaving the Continue button loading.

Note

Fix AuthStartViewModel.startAuth to surface errors in sign-in-only mode

In sign-in-only mode (withSignUp = false), auth failures never updated state, leaving the UI stuck on Loading with no error shown. The onFailure branch in AuthStartViewModel.kt was gated on a ClerkErrorResponse type check inside a withSignUp condition, so all failures in sign-in mode were silently dropped. The fix removes the type check and always emits AuthState.Error unless the error code warrants a sign-up fallback.

🖇️ Linked Issues

Resolves MOBILE-602, which identified that wrong identifier, throttle, and network errors in sign-in-only mode left the UI in a permanent loading state.

^{Macroscope summarized 7b38636.}

Summary by CodeRabbit

• Bug Fixes
  • Improved sign-in error handling to correctly distinguish recoverable errors from unexpected failures.
  • Sign-in now displays the relevant backend error message when available, or a clear generic message when no details are provided.
• Tests
  • Added coverage for API and unknown sign-in failure scenarios, including expected loading and error state transitions.

[coderabbitai]

📝 Walkthrough

Walkthrough

Sign-in failure handling now checks backend error codes directly to decide between sign-up fallback and error state emission. Tests cover API failures with specific messages and unknown failures with the generic message.

Changes

Sign-in error handling

Layer / File(s)	Summary
Update sign-in failure routing source/ui/src/main/java/com/clerk/ui/auth/AuthStartViewModel.kt, source/ui/src/test/java/com/clerk/ui/auth/AuthViewModelTest.kt	Recognized form and invitation error codes trigger sign-up; other API and unknown failures emit AuthState.Error with the appropriate message, covered by new tests.

Estimated code review effort: 2 (Simple) | ~10 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title is concise and accurately summarizes the main change: surfacing sign-in-only auth errors.
Description check	✅ Passed	The description matches the required template and includes the change rationale, reviewer focus, and screenshots.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch sam/mobile-602-spike-sign-in-only-mode-swallows-auth-errors

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[coderabbitai]

🧹 Nitpick comments (2)

source/ui/src/test/java/com/clerk/ui/auth/AuthViewModelTest.kt (1)

86-107: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Add coverage for the invitation fallback code.

The supplied fallback test covers form_identifier_not_found, but not invitation_account_not_exists, which is now an explicit branch in AuthStartViewModel.signIn. Add a SignInOrUp test asserting that this code invokes SignUp.create and reaches SignUpSuccess.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@source/ui/src/test/java/com/clerk/ui/auth/AuthViewModelTest.kt` around lines
86 - 107, Add a SignInOrUp test covering the invitation_account_not_exists
branch in AuthStartViewModel.signIn. Mock SignInOrUp to return that API error,
verify SignUp.create is invoked with the expected parameters, and assert the
flow reaches SignUpSuccess.

source/ui/src/main/java/com/clerk/ui/auth/AuthStartViewModel.kt (1)

182-188: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Use when for the SignIn.create(...) failure routing.

This path still uses .onFailure; wrap SignIn.create(...) with when (val result = ...) and move the shouldSignUp fallback into the ClerkResult.Failure branch to match the ClerkResult pattern.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@source/ui/src/main/java/com/clerk/ui/auth/AuthStartViewModel.kt` around lines
182 - 188, Replace the SignIn.create(...).onFailure routing with when (val
result = SignIn.create(...)), handling success and ClerkResult.Failure
explicitly. Move the matchingCodes/shouldSignUp fallback into the
ClerkResult.Failure branch, preserving signUp for matching errors and
AuthState.Error for all other failures.

Source: Coding guidelines

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@source/ui/src/main/java/com/clerk/ui/auth/AuthStartViewModel.kt`:
- Around line 182-188: Replace the SignIn.create(...).onFailure routing with
when (val result = SignIn.create(...)), handling success and ClerkResult.Failure
explicitly. Move the matchingCodes/shouldSignUp fallback into the
ClerkResult.Failure branch, preserving signUp for matching errors and
AuthState.Error for all other failures.

In `@source/ui/src/test/java/com/clerk/ui/auth/AuthViewModelTest.kt`:
- Around line 86-107: Add a SignInOrUp test covering the
invitation_account_not_exists branch in AuthStartViewModel.signIn. Mock
SignInOrUp to return that API error, verify SignUp.create is invoked with the
expected parameters, and assert the flow reaches SignUpSuccess.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 203371ef-5373-4055-862d-4b122315a453

📥 Commits

Reviewing files that changed from the base of the PR and between c24f404 and 7b38636.

📒 Files selected for processing (2)

• source/ui/src/main/java/com/clerk/ui/auth/AuthStartViewModel.kt
• source/ui/src/test/java/com/clerk/ui/auth/AuthViewModelTest.kt