LinearRouter and PatternRouter does not support regexp "quantifiers"

[yusukebe]

What version of Hono are you using?

4.0.1

What runtime/platform is your app running on?

Cloudflare Workers

What steps can reproduce the bug?

import { Hono } from 'hono'
import { getRouterName } from 'hono/dev'
import { LinearRouter } from 'hono/router/linear-router'
import { PatternRouter } from 'hono/router/pattern-router'
import { RegExpRouter } from 'hono/router/reg-exp-router'
import { TrieRouter } from 'hono/router/trie-router'

const routers = [new TrieRouter(), new RegExpRouter(), new LinearRouter(), new PatternRouter()]

for (const router of routers) {
  const app = new Hono({ router })
  app.get('/year/:year{[0-9]{4}}/month/:month{[0-9]{1,2}}', (c) => {
    return c.json(c.req.param())
  })
  const res = await app.request('/year/2024/month/2')
  console.log(getRouterName(app), res.status)
}

What is the expected behavior?

TrieRouter 200
RegExpRouter 200
LinearRouter 200
PatternRouter 200

What do you see instead?

TrieRouter 200
RegExpRouter 200
LinearRouter 404
PatternRouter 404

Additional information

No response

[usualoma]

I think we should use (?:{(?:(?:{[\d,]+})|[^}])+})? instead of (?:{[^}]+})?). The regular expression shown in #2193 also meets the specification, but is slightly longer.

[yusukebe]

@usualoma

How about using (?:{[^/]+})?) as mentioned on the following:

https://github.com/honojs/hono/pull/2193/files#r1487327201

[usualoma]

@yusukebe Ah, you're right, that would be better! > (?:{[^/]+})?

I think (?:{(?:(?:{[\d,]+})|[^}])+})? is more faithful to the spec, but (?:{[^/]+})? is also used in existing codes such as RegExpRouter, and I think this is simpler and better!

[the-fukui]

@yusukebe @usualoma Hi, I was working on https://github.com/honojs/hono/pull/2193. Thank you for the suggestion! The pattern (?:{[^/]+})? seems to be shorter and smarter, so I will commit in the PR.