#77599 🐛 bug: fix infinite loop caused by redirect function with empt…

[sergioramirez-dev]

Fix: Prevent infinite redirect loop for redirect("")

Problem

Calling redirect("") results in an infinite redirect loop in the browser due to an empty Location header, which resolves to the current URL.

Cause

The redirect response sets Location: "", and the client router does not guard against self-redirects.

Solution

Validate the redirect target and reject empty strings.

if (!url || url.trim() === "") {
  throw new Error("Invariant: attempted to redirect to an empty URL. This causes infinite redirect loops.");
}

Changes

• Added validation for empty redirect targets
• Ensured Location header is never empty.

Tests

Throws on redirect("") and redirect(" ")
Valid redirects unchanged.

Notes

This prevents undefined behavior and improves error clarity. Treating empty strings as invalid is preferred over silent normalization.

Closes #77599

[nextjs-bot]

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[nextjs-bot]

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• approve CI run for commit: cfed4e6

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[vercel]

Additional Suggestion:

The permanentRedirect function is missing the empty URL guard that was added to redirect, allowing permanentRedirect("") to cause an infinite redirect loop with a 308 status code.

[sergioramirez-dev]

Have added URL guard to permanentRedirect and added just one test condition.