fix: throw TypeError for invalid url in res.redirect#6957
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MirrorDNA-Reflection-Protocol wants to merge 1 commit intoexpressjs:masterfrom
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fix: throw TypeError for invalid url in res.redirect#6957MirrorDNA-Reflection-Protocol wants to merge 1 commit intoexpressjs:masterfrom
MirrorDNA-Reflection-Protocol wants to merge 1 commit intoexpressjs:masterfrom
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When res.redirect is called with undefined/null or non-string URL, it now throws a TypeError instead of sending a malformed Location header with 'undefined' as the value. The deprecation warnings are preserved for backwards compatibility tracking, but the function now throws immediately after the warning to prevent the malformed HTTP response. Fixes expressjs#6941
krzysdz
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Dec 26, 2025
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Duplicate of #6404.
Other than this, here are a couple comments for you:
- Avoid making unrelated formatting changes, as this makes PRs harder to review.
- #6404 has not landed yet, because there is no branch for 6.x and this is a breaking change.
- It doesn't make sense to print a deprecation notice and throw an error at the same time. The deprecation is there to signal that the behaviour will change in a future major version.
- Such changes should be covered by tests.
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Summary
Fixes #6941 —
res.redirect(undefined)was sending a malformedLocation: undefinedheader instead of throwing an error.Changes
When
res.redirectis called with:undefined,null, or empty URLIt now throws a
TypeErrorinstead of sending a malformed HTTP response.Before:
After:
The deprecation warnings are preserved for backwards compatibility tracking, but the response is no longer sent.
Testing
This change may require updating existing tests that expect deprecated behavior. The fix ensures HTTP responses are always valid per spec.