Do not throw when a redirect URL has a malformed escape sequence

[RaphaelFakhri]

Problem

safeRedirect passes the target URL through decodeURI before it builds the redirect. decodeURI throws a URIError when the string contains a malformed escape sequence such as %zz. A return-url query parameter or a room URL with such a sequence makes the set-username action and the root loader fail with a 500 instead of redirecting.

For example, open /set-username?return-url=%2Froom%2F100%25zz without a display name set and submit the form. The action throws URIError: URI malformed.

Solution

Decode through a small helper that falls back to the raw value when decodeURI throws. The existing scheme check runs on that value unchanged.

Testing

npx vitest --watch false app/utils/safeReturnUrl.test.ts

The new test file covers a normal redirect, the existing scheme check, and two URLs with a malformed sequence. Without the change, the two malformed cases fail with URIError: URI malformed. With the change, all four tests pass.