🪤 fix: Avoid express-rate-limit v8 ERR_ERL_KEY_GEN_IPV6 False Positive#12333
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express-rate-limit v8 calls keyGenerator.toString() and throws ERR_ERL_KEY_GEN_IPV6 if the source contains the literal substring "req.ip" without "ipKeyGenerator". When packages/api compiles req?.ip to older JS targets, the output contains "req.ip", triggering the heuristic. Bracket notation (req?.['ip']) produces identical runtime behavior but never emits the literal "req.ip" substring regardless of compilation target. Closes #12321
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Pull request overview
This PR updates the removePorts rate-limiter key generator to avoid an express-rate-limit v8 false positive (ERR_ERL_KEY_GEN_IPV6) caused by TypeScript downlevel output containing the literal substring req.ip.
Changes:
- Replace
req?.ipwith bracket-notation accessreq?.['ip']to prevent emitted JS from containingreq.ip. - Expand the function doc comment to document why bracket notation is required for
express-rate-limitv8 compatibility.
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Add a test that verifies removePorts.toString() does not contain "req.ip", guarding against reintroduction of the ERR_ERL_KEY_GEN_IPV6 false positive. Fix a misleading test description and remove a redundant type annotation on a trivially-inferred local.
danny-avila
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jcbartle
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May 11, 2026
danny-avila#12333) * fix: avoid express-rate-limit v8 ERR_ERL_KEY_GEN_IPV6 false positive express-rate-limit v8 calls keyGenerator.toString() and throws ERR_ERL_KEY_GEN_IPV6 if the source contains the literal substring "req.ip" without "ipKeyGenerator". When packages/api compiles req?.ip to older JS targets, the output contains "req.ip", triggering the heuristic. Bracket notation (req?.['ip']) produces identical runtime behavior but never emits the literal "req.ip" substring regardless of compilation target. Closes danny-avila#12321 * fix: add toString regression test and clean up redundant annotation Add a test that verifies removePorts.toString() does not contain "req.ip", guarding against reintroduction of the ERR_ERL_KEY_GEN_IPV6 false positive. Fix a misleading test description and remove a redundant type annotation on a trivially-inferred local.
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Summary
express-rate-limitv8 callskeyGenerator.toString()and throwsERR_ERL_KEY_GEN_IPV6if the source contains the literal substringreq.ipwithoutipKeyGenerator. Whenpackages/apicompilesreq?.ipto older JS targets, the output containsreq.ip, triggering the heuristic.req?.['ip']) produces identical runtime behavior but never emits the literalreq.ipsubstring regardless of compilation target.Follow-up to #12319.
Test plan
removePortstests pass (including new.toString()regression guard)req['ip']— noreq.ipsubstring inremovePorts.toString()express-rate-limitv8 heuristic simulation:Would trigger ERR_ERL_KEY_GEN_IPV6: false