fix(mount): resolve dynamic path prefixes

[usualoma]

fixes #5546

This PR resolves dynamic prefixes using the request path and the router’s captured parameter values. It also handles intermediate wildcards, including patterns such as /x*/y/*.

Although callers can work around this with replaceRequest, I think this is a case that mount() should handle by default. Since mount() was recently extracted from core into middleware, the additional code seems reasonable.

The implementation accesses the internal match result to obtain parameter values before param() decodes them. Those values are needed to calculate the correct offsets in the request path. This introduces a dependency on internal structures, but I think that is acceptable for middleware shipped with Hono.

The author should do the following, if applicable

• Add tests
• Run tests
• pnpm run check:fix to format and lint the code

[github-actions]

Bundle size check

	main (552ea02)	#5553 (2020ed0)	+/-
Bundle Size (B)	18,335B	18,663B	+328B
Bundle Size (KB)	17.91K	18.23K	+0.32K

Compiler Diagnostics (tsc)

	main (552ea02)	#5553 (2020ed0)	+/-
Files	83	84	+1
Lines	59,446	59,530	+84
Identifiers	60,625	61,878	+1,253
Symbols	106,532	115,720	+9,188
Types	163,092	171,784	+8,692
Instantiations	414,023	452,803	+38,780
Memory used	208,711K	193,423K	-15,288K
I/O read	0.01s	0.01s	0s
I/O write	0s	0s	0s
Parse time	0.29s	0.29s	0s
Bind time	0.1s	0.11s	+0.01s
Check time	1.25s	1.33s	+0.08s
Emit time	0s	0s	0s
Total time	1.65s	1.74s	+0.09s

Compiler Diagnostics (typescript-go)

	main (552ea02)	#5553 (2020ed0)	+/-
Files	215	216	+1
Lines	121,008	121,092	+84
Identifiers	107,353	108,609	+1,256
Symbols	181,164	189,748	+8,584
Types	262,348	271,038	+8,690
Instantiations	621,588	660,480	+38,892
Memory used	153,867K	158,615K	+4,748K
Memory allocs	1,781,675	1,852,105	+70,430
Config time	0.001s	0.001s	0s
BuildInfo read time	0.001s	0s	-0.001s
Parse time	0.086s	0.106s	+0.02s
Bind time	0s	0s	0s
Check time	0.459s	0.519s	+0.06s
Emit time	0.004s	0.004s	0s
Changes compute time	0.021s	0.031s	+0.01s
Total time	0.601s	0.699s	+0.098s

---

Reported by octocov

[github-actions]

HTTP Performance Benchmark

Framework	Runtime	Average	Ping	Query	Body
hono (origin/main)	bun	85,668.69	105,438.49	83,772.56	67,795.01
hono (current)	bun	102,512.58	126,352.85	98,519.65	82,665.23
Change		+19.66%	+19.84%	+17.60%	+21.93%

[codecov]

Codecov Report

❌ Patch coverage is 95.23810% with 1 line in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (v5@b0d28c4). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
src/middleware/mount/index.ts	95.23%	1 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##             v5    #5553   +/-   ##
=====================================
  Coverage      ?   79.96%           
=====================================
  Files         ?      131           
  Lines         ?    10170           
  Branches      ?     2244           
=====================================
  Hits          ?     8132           
  Misses        ?     2038           
  Partials      ?        0           

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