Fix Google sign-in infinite loading in browser pane

[austinywang]

Summary

• add a regression seam/test for nil-target browser popup fallback routing
• stop rerouting scripted .other nil-target navigations back into new tabs
• preserve the WKUIDelegate.createWebViewWith popup path so Google OAuth keeps window.opener semantics

Testing

• not run locally per repo policy
• ./scripts/reload.sh --tag fix-google-auth1491 reached ** BUILD SUCCEEDED **

Fixes #1491

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Summary by cubic

Fixes Google sign-in infinite loading by preserving popup opener semantics and not rerouting scripted .other nil-target navigations to new tabs. Fixes #1491.

• Bug Fixes
  • Handle scripted popups via WKUIDelegate.createWebViewWith so OAuth window.opener stays intact.
  • Fall back to a new tab only for target=_blank link activations; added regression tests for this behavior.

^{Written for commit 4ef164b. Summary will update on new commits.}

Summary by CodeRabbit

• Bug Fixes

  • Improved handling of navigation when no target is specified, with smarter fallback behavior that distinguishes between user-initiated link clicks and scripted actions.

• Tests

  • Added test coverage for nil-target navigation scenarios.

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Project	Deployment	Actions	Updated (UTC)
cmux	Ready	Preview, Comment	Mar 16, 2026 1:47am

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Caution

Review failed

Pull request was closed or merged during review

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: bc5f59a8-5e29-4cbf-91ad-3c7852f05bf1

📥 Commits

Reviewing files that changed from the base of the PR and between bd17886 and 4ef164b.

📒 Files selected for processing (2)

• Sources/Panels/BrowserPanel.swift
• cmuxTests/CmuxWebViewKeyEquivalentTests.swift

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📝 Walkthrough

Walkthrough

A helper function was added to centralize the decision logic for whether nil-target navigation should fallback to opening in a new tab. This function is now used in two navigation decision paths: the WKNavigationAction policy handler and the UI delegate's createWebViewWith flow, with updated comments reflecting the new handling.

Changes

Cohort / File(s)	Summary
Browser Navigation Logic Sources/Panels/BrowserPanel.swift	Added helper function browserNavigationShouldFallbackNilTargetToNewTab() to determine nil-target fallback behavior based on navigation type. Updated WKNavigationAction policy and createWebViewWith flows to use this centralized decision logic.
Navigation Tests cmuxTests/CmuxWebViewKeyEquivalentTests.swift	Added BrowserNilTargetFallbackDecisionTests class with two test cases validating that non-link navigation (.other) does not fallback to new tab, while link-activated navigation does.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Possibly related PRs

• feat: support window.open() popup windows #1150: Modifies the same BrowserPanel.swift navigation and createWebViewWith decision paths; this PR's helper function complements the popup-routing logic from that PR.

Poem

🐰 A nil-target leap, now smart and true,
Link hops fallback, but scripts pass through—
Two paths align with logic neat,
Navigation's dance, swift and fleet! ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The PR title clearly summarizes the main objective: fixing Google sign-in infinite loading. It directly relates to the primary issue being addressed (#1491).
Description check	✅ Passed	The PR description covers the summary (what changed and why) and testing approach, but lacks demo video and the review trigger checklist is incomplete (videos and local testing excluded per repo policy).
Linked Issues check	✅ Passed	The PR directly addresses #1491 by implementing the fix to preserve popup semantics and prevent rerouting scripted .other navigations, aligning with the requirement to restore Google OAuth flow.
Out of Scope Changes check	✅ Passed	All changes are focused on fixing the nil-target navigation fallback logic and adding regression tests, which are directly scoped to the issue requirements. No unrelated changes detected.

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✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch issue-1491-google-signin-infinite-loading

📝 Coding Plan

• Generate coding plan for human review comments

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[cubic-dev-ai]

No issues found across 2 files