fix issues with complex multi-param#349
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Well, test on Node.js 26 still depends on #348. |
jimmyolo
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Jul 21, 2026
Cross-model review (Codex) found that dropping the boundary lookahead let a custom capture that can match empty (e.g. `:p(.*)` or `:p([^-]*)`) match an empty param before a following literal — `/x/:p(.*)-end` matched `/x/-end`, which Express (path-to-regexp@0.1.13) rejects. The prior lookahead form was also wrong here (it rejected the non-empty `/x/abc-end` that Express accepts), so neither form matched the oracle. path-to-regexp compiles a custom capture's first `*` to `(.*)`, turning `.*` into `.(.*)` and `[^-]*` into `[^-](.*)` — forcing >=1 char. Replicate that one transform on the captured regex. Differential-verified against path-to-regexp@0.1.13: 0 divergences across the `.*`/`[^-]*` empty-and-nonempty cases, PR dimdenGD#349's multi-param cases, and the alternation-before-literal case. New parity assertions `/opt/:p(.*)-end` -> `/opt/-end` (404) and `/opt/abc-end` (match); red without this change. Reviewed-by: Codex gpt-5-codex Assisted-by: claude:claude-opus-4-8 (medium)
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This PR fixes multiple issues with the current matching strategy with regards to multi-param routes:
-and.as they are not meant verbatim there([^/]+)), but are wrongly optimized (happening in app but not router, which confused me a lot initially)The ideas come from my personal use case and the official Express.js 4.x documentation, with the official
path-to-regexp0.1.x as a loose reference.Not sure if the test cases are okay like this (may need to reorganize), but they definitely serve the purpose of identifying the exact problems with the current implementation.