ruby-grape / grape / 24696162603

97%

master: 97%

Pull #2691

github

Precompute prefix list in Versioner::Path

`Versioner::Path#before` built `[mount_path, Grape::Router.normalize_path(prefix)]`
on every request and iterated it, filtering nil/empty/'/' entries with a guard
clause on each element. Both `mount_path` and `prefix` are fixed at mount time,
so this work is redundant.

Memoize a pre-filtered `@prefixes` array in `initialize` (the middleware dup in
`Middleware::Base#call` shallow-copies ivars, so the frozen array is shared
across request dups for free). The per-request loop simplifies to
`if path_info.start_with?(path)`.

## Benchmark (1k iterations)

  current                    1.09 M i/s, 80KB / 2k objects
  variant A (memoize normalize) 1.34 M i/s, 80KB / 2k objects
  variant B (memoize list)   2.61 M i/s, 40KB / 1k objects  (2.38x faster, 2x fewer)

Shipping variant B.

No behavior change; all 2,236 specs pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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