url: speed up setters, search params, and URLPattern

[anonrig]

Why

URL setters always reparsed the href, including when the assigned value was already the serialized component. URLSearchParams built from a record walked Reflect.ownKeys, and every get / has converted the name again. URL.canParse and URLPattern.test took the slow string callback for ASCII input.

What

A setter skips ada when the new value matches the component already stored on the href, and skips the slice when the lengths differ. An empty host or hostname, and a lone ? or #, still go through ada, because those writes are not idempotent. Record URLSearchParams uses Object.keys when there are no symbol keys. Repeated get, getAll, and has of the same string skip a second USVString conversion. URL.canParse and URLPattern.prototype.test use the one-byte fast API; two-byte strings stay on the slow path.

benchmark/compare.js --runs 5 on macOS arm64 Release, against the parent commit built with the same toolchain. Stars in that tool mark a significant difference; the rows below are significant. Assigning the current pathname on its own went from 3.9M to 106M ops/s. Setting a different pathname was flat (+3%).

Benchmark	Change
whatwg-url-properties href, with base	+150%
whatwg-url-properties password, with base	+118%
whatwg-url-properties port, with base	+113%
whatwg-url-properties protocol, with base	+110%
whatwg-url-properties username, with base	+108%
whatwg-url-properties pathname, with base	+76%
whatwg-url-properties host, with base	+71%
whatwg-url-properties hash, with base	+64%
whatwg-url-properties search, with base	+62%
whatwg-url-properties hostname, with base	+55%
whatwg-url-canParse long	+54%
whatwg-url-canParse short	+45%
whatwg-url-canParse ws	+29%
whatwg-url-canParse file	+28%
whatwg-url-canParse javascript	+28%
whatwg-url-canParse auth	+19%
url-searchparams-creation object, noencode	+68%
url-searchparams-read has one	+88%
url-searchparams-read get one	+79%
urlpattern-test exact pathname/search/hash	+32%
urlpattern-test hostname	+32%

test/parallel/test-whatwg-url*, test-urlpattern*, test-url*, and WPT url / urlpattern pass. A closed-source coding agent assisted with the implementation.

[nodejs-github-bot]

Review requested:

• @nodejs/url

[codecov]

Codecov Report

❌ Patch coverage is 78.64078% with 66 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.28%. Comparing base (67a4416) to head (078b443).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
src/node_url_pattern.cc	49.35%	35 Missing and 4 partials ⚠️
lib/internal/url.js	92.27%	15 Missing and 1 partial ⚠️
src/node_url.cc	56.00%	10 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #66188      +/-   ##
==========================================
- Coverage   90.28%   90.28%   -0.01%     
==========================================
  Files         790      790              
  Lines      272044   272231     +187     
  Branches    51949    51990      +41     
==========================================
+ Hits       245625   245782     +157     
- Misses      16915    16966      +51     
+ Partials     9504     9483      -21     

Files with missing lines	Coverage Δ
src/node_url.h	100.00% <ø> (ø)
src/node_url_pattern.h	0.00% <ø> (ø)
src/node_url.cc	77.80% <56.00%> (-1.15%)	⬇️
lib/internal/url.js	92.83% <92.27%> (-0.44%)	⬇️
src/node_url_pattern.cc	77.25% <49.35%> (-6.28%)	⬇️

... and 20 files with indirect coverage changes

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[jasnell]

The test coverage gaps in this should be looked at