fix(react-router): Catch thrown nullish value and prevent nullish

[joseinaqa]

loadPromise from being thrown

The issue happens in circumstances where match.status === 'redirected' but the loadPromise is nulled.
Reproduction is possible by using
https://github.com/joseinaqa/redirect-race-app and after this change does not happen anymore.

Summary by CodeRabbit

• Bug Fixes
  • Improved error handling by normalizing “nullish thrown” cases so boundaries always receive a real Error and reliably report failures.
  • Preserved component stack details when available, improving debuggability for certain caught-error scenarios.
  • Fixed suspense/loading behavior to prevent “pending” throws from failing when match promises are undefined, using a safe never-resolving fallback.
  • Ensured client-side rethrows always throw a concrete error instead of a potentially nullish value.

[coderabbitai]

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: e9e4b536-cc58-4fe7-bc08-09b101de1ec3

📥 Commits

Reviewing files that changed from the base of the PR and between dbd4754 and 61fa627.

📒 Files selected for processing (2)

• packages/react-router/src/CatchBoundary.tsx
• packages/react-router/src/Match.tsx

🚧 Files skipped from review as they are similar to previous changes (2)

• packages/react-router/src/Match.tsx
• packages/react-router/src/CatchBoundary.tsx

---

📝 Walkthrough

Walkthrough

CatchBoundary now normalizes nullish thrown errors and updates the stored stack before calling onCatch. Match now falls back to a shared never-resolving promise when Suspense would otherwise throw nothing, and client error rethrows now always produce a concrete Error.

Changes

Error and Suspense Handling Fixes

Layer / File(s)	Summary
Nullish error normalization in CatchBoundary packages/react-router/src/CatchBoundary.tsx	Nullish thrown errors are replaced with a new Error, componentDidCatch patches the stored error's stack, and onCatch receives the normalized error.
permaPendingPromise fallback for Suspense throws packages/react-router/src/Match.tsx	A shared permaPendingPromise is introduced and used as a fallback across server and client pending, redirect, and error throw sites to ensure a Promise is always thrown for Suspense.

Estimated code review effort: 2 (Simple) | ~12 minutes

Sequence Diagram(s)

sequenceDiagram
  participant MatchInner
  participant getMatchPromise
  participant ReactSuspense

  MatchInner->>getMatchPromise: request match promise
  getMatchPromise-->>MatchInner: promise or undefined
  alt promise is undefined
    MatchInner->>ReactSuspense: throw permaPendingPromise
  else promise exists
    MatchInner->>ReactSuspense: throw match promise
  end

Loading

Suggested labels: package: react-router

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title is directly related to the PR’s main fix: handling nullish thrown values in react-router.
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 unit tests (beta)

• Create PR with unit tests

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[coderabbitai]

Actionable comments posted: 1

🤖 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.

Inline comments:
In `@packages/react-router/src/Match.tsx`:
- Line 523: The Match.tsx error-handling path currently throws
permaPendingPromise when match.error is nullish, which keeps the route suspended
instead of reaching the error boundary. Update the logic in Match to throw a
synthetic Error in this branch, and keep using match.error when present so
client error states render correctly rather than staying on the pending
fallback.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: a7b45fc0-6aa0-4f09-8dcf-8eda61c7602c

📥 Commits

Reviewing files that changed from the base of the PR and between 208100b and dbd4754.

📒 Files selected for processing (2)

• packages/react-router/src/CatchBoundary.tsx
• packages/react-router/src/Match.tsx