url: end the authority where new URL() ends it

[robobun]

Problem

• bun install dials the registry host that new URL() reads, but chooses the credentials with bun_url::URL::parse. Some spellings give two different hosts. --registry=http://u:p@first.example\x@second.example/ sends Basic base64("u:p@first.example\x") to second.example. A regression from fetch: proxy, TLS identity and error fixes; add Bun.FetchSession #42692.
• registry=http://first.example\@second.example/ with //second.example/:_authToken=T sends Bearer T to first.example. So does registry=http:first.example://second.example/. Both predate fetch: proxy, TLS identity and error fixes; add Bun.FetchSession #42692.
• NetworkTask.rs has its own copy of the scan. The dependency http://u:p@first.example\x@second.example/pkg.tgz sends Basic of u:p@first.example\x to second.example. npm sends u:p to first.example.

Fix

• URL::ends_authority is the one rule for where the userinfo, the host and the port end: /, ?, #, and a \ for http, https, ws, wss, ftp and file. NetworkTask::split_url_userinfo shares it. parse_protocol reads no host behind a second scheme.
• A proxy is the exception. The client alone reads it, and http://DOMAIN\user:pass@proxy:8080 is a real login. make_client reads every proxy with URL::parse_single_reader, where a \ stays userinfo.
• Correct because URL::parse now names the origin that new URL() names, so the credential choice and the dial agree. A differential over 31,256 generated URLs finds no case where they name different usable hosts.
• Verified: 9 new cases fail with src/ at the base and pass with this change. 5 more guard what must not change (notes).

Background

• bun_url::whatwg wraps the WebKit parser behind new URL(). bun_url::URL::parse slices a string and copies nothing.
• WHATWG calls those six schemes special. In them a \ acts as a /, so it ends the authority (user:pass@host:port).
• Scope::set_url (src/install/npm.rs) stores the registry URL as the WHATWG parser serializes it. RegistryAuth::matches (src/ini/lib.rs) and NpmRegistry::from_url choose the credentials from URL::parse.

Notes

Fail-before. With src/ and packages/ checked out from 55c1106, the base these commits were written on (git checkout --no-overlay <base> -- src/ packages/, a debug build): the 7 npmrc.test.ts cases fail, the proxy.test.ts parser table fails, and the tarball case of bun-install.test.ts fails. The 4 userinfo cases of npmrc.test.ts (--registry, .npmrc, bunfig.toml, BUN_CONFIG_REGISTRY) send Basic of u:p@first.example\x to second.example. The 3 token cases send Bearer second-host-SECRET-token to first.example. The tarball case sends Basic of u:p@127.0.0.1:first\x to the second host. On 1.4.3-canary.1+09bb54630, which predates #42692, the 4 userinfo cases pass and the rest fail. That separates the regression from the older defect.

Five cases guard what must not change. They pass with src/ at the base and with this change. Each failed on an earlier revision of this branch.

• fetch("blob:http://example.com/id") and fetch("view-source:http://example.com/") reject with protocol must be http:, https: or s3:.
• fetch("localhost:PORT/hello"), a string new URL() reads with the scheme localhost, is an http request to that host and port.
• http_proxy=http://DOMAIN\user:pass@host reaches the proxy with Basic of DOMAIN\user:pass, for fetch() and for fetch("s3://…"). With the make_client line removed both fail (EAI_AGAIN on DOMAIN\user).

parse_protocol gives every caller the protocol it always gave: the text in front of a :// that comes before any /, ? or %. blob:http://host/id still has the protocol blob:http, which fetch refuses. localhost:3000/api still has none. The change is that the authority behind that text is read only when the text is a scheme as RFC 3986 §3.1 spells it: a letter, then letters, digits, +, - or .. For http:first.example://second.example/ the host is then read from the start of the string (http), which matches no .npmrc key.

What URL::parse still cannot give is the path. It copies nothing, so it cannot turn the \ of http://host\a/b into a / as new URL() does. pathname is / for such a string. In CI on Windows the request for that dependency reached the first host with the \ as a / in its path, so the tarball test compares the host and the credentials and leaves the path out.

Other shapes checked against new URL() with the fixed build: \x@, \\@, a trailing dot, \@[::1]:8080, userinfo with ports, IPv6, %75, ;, :080, and #@. Each names the same origin as new URL(). Two still differ and fail closed: a tab in the authority (new URL() drops it, this keeps it in the name) and the second-scheme form above.

The dist.tarball door is unchanged, measured before and after. A manifest tarball of http://cdn.example\@registry.example/x.tgz requests registry.example with the registry token in both builds. No credential crosses parties there.

Overlap. #41667 fixes the registry door one layer up: NpmRegistry::from_url and the two same-host checks in PackageManagerOptions.rs parse with the WHATWG parser. It predates #42692 and does not change URL::parse, so RegistryAuth::matches and the tarball split keep the old reading. #40423 reworks the .npmrc credential lookup in src/ini/lib.rs and does not touch src/url/lib.rs.

Suites run on the debug build of this branch.

• proxy.test.ts 92 pass. npmrc.test.ts 47 pass. fetch-args.test.ts 85 pass. bun-install-registry.test.ts 253 pass. config-precedence.test.ts 51 pass. fetch.tls.test.ts 41 pass. fetch-session.test.ts 32 pass. byte-search.test.ts and comment-cop.test.ts pass.
• bun-install.test.ts: 229 pass, 13 fail. The same 13 fail at the base. They need Bitbucket, GitLab or another public host.
• On an earlier revision of this branch, not repeated after the last change: bun-add.test.ts 71 pass, bun-publish.test.ts 46 pass, bun-audit.test.ts 182 pass, bun-serve-static.test.ts 46 pass, two S3 files 14 pass, test/internal/source-lints 174 pass, serve.test.ts 305 pass with 2 failures that also fail at the base, fetch.test.ts 351 pass with 21 failures. Of those 21, the 2 redirect failures fail at the base too. I did not baseline the other 19. They are the UTF-16 GC, root-only permission, IPv6 localhost and public-internet tests that fetch: proxy, TLS identity and error fixes; add Bun.FetchSession #42692 also reports as failing on a debug build.
• bun run rust:check-all: 12 targets ok.

The differential compares the origin URL::parse names with the one new URL() names, over every generated string new URL() accepts with a host: 21,521 name the same origin, 9,735 give a host that is not a name a credential can be keyed to, and none gives a different usable host. The generator mixes @, :, \, /, ?, #, %40, brackets, tabs, ports and a second scheme around the host, for nine schemes.

Miri. URL::parse reaches strings::eql_case_insensitive_ascii, which calls libc strncasecmp, and Miri has no shim for it. Under cfg(miri) the helper compares with eq_ignore_ascii_case, as bun_highway does for its kernels. bun run rust:miri passes for all 16 crates. Miri runs the unit tests of bun_url, so the new rules have three there: where the authority ends, the proxy reading, and no host behind a second scheme.

Builds. The figures above are from a debug build of these commits on 55c1106. After the rebase onto #42851 (LLVM 23) I built this head again: proxy.test.ts, npmrc.test.ts and fetch-args.test.ts 224 pass, bun-install.test.ts 229 pass with the same 13 public-host failures, rust:check-all 12 targets ok.

Windows and macOS ran in CI only. The head before the rebase (the same files) passed all 16 Windows test jobs. The head before that failed the tarball case on both Windows lanes, because the test then expected no request at the first host.

Not run. cargo test -p bun_url does not link locally (highway_memmem), as #42692 notes. The perf stat bench of #42692 was not run: each parse with a scheme adds up to six short compares, once in userinfo_end and once in parse_host.

---

no test proof · iteration 0 · platform-specific test(s) that do not run on this machine, deferring to CI, which covers all platforms: test/js/bun/http/proxy.test.ts, test/cli/install/bun-install.test.ts

[coderabbitai]

Walkthrough

The URL parser now separates WHATWG and parser-only authority rules. Proxy, install, HTTP, and fetch paths use the updated parsing behavior. Tests cover backslashes, credentials, schemes, and unsupported protocols. Miri uses a Rust-native ASCII comparison implementation.

Changes

URL authority parsing

Layer / File(s)	Summary
Authority and protocol parsing rules src/url/lib.rs	URL stores its authority termination rule. Parsing, host scanning, userinfo detection, and userinfo removal share scheme-specific boundaries and stricter scheme validation.
Proxy and install integration src/dotenv/env_loader.rs, src/http/..., src/install/NetworkTask.rs, test/cli/install/*	Proxy and registry paths use parse_single_reader. Tests cover backslash-separated authorities, chained schemes, and credential isolation.
Proxy and fetch regression coverage test/js/bun/http/proxy.test.ts, test/js/web/fetch/fetch-args.test.ts	Tests cover proxy credentials, authority parsing, scheme-less HTTP URLs, and unsupported protocols.

Platform string comparison

Layer / File(s)	Summary
Miri ASCII comparison src/bun_core/lib.rs	Miri uses Rust’s eq_ignore_ascii_case. Other platform-specific implementations remain unchanged.

Suggested reviewers: alii

Priority: ⬆️ High

Merge Risk: 🔵 Low · up to 108bc

A narrow file-URL validation gap can treat invalid credential-bearing URLs as filesystem paths, but the impact is localized.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly summarizes the main change: authority termination now matches new URL() behavior.
Description check	✅ Passed	The description explains the problem, fix, background, scope, and verification results. It does not use the template headings exactly, but it provides the required change summary and test evidence in …

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Actionable comments posted: 2

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Inline comments:
In `@src/url/lib.rs`:
- Line 706: Update the authority parsing around url.userinfo_end to reject file
URLs whenever the authority contains @, returning the existing parse failure
rather than storing username or password; add regression coverage for
credentials followed by both a backslash and a forward slash.

In `@test/cli/install/npmrc.test.ts`:
- Line 809: Replace the parameterized test.each suite with describe.each, and
move its asynchronous assertion into a nested test within each generated
describe block. Preserve the existing test cases, setup, and assertions while
applying this structure to the parameterized suite.

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[robobun]

Status: fix pushed, head 108bc50. All review threads are answered and resolved. cargo miri test passes locally for all 16 crates.

What this PR changes, in one line: URL::parse ends the userinfo, the host and the port of an http(s) URL where new URL() ends them, so bun install picks credentials for the host it dials.

How I reproduced it. A loopback Bun.serve acts as the HTTP proxy of bun install. It records the host and the Authorization header of each request and answers 404. No name is resolved.

With src/ and packages/ checked out from the merge-base 55c1106, on a debug build:

• --registry='http://u:p@first.example\x@second.example/' requests second.example with Basic of u:p@first.example\x. new URL() reads the host as first.example.
• .npmrc with registry=http://first.example\@second.example/ and //second.example/:_authToken=T requests first.example with Bearer T.
• The dependency http://u:p@127.0.0.1:A\x@127.0.0.1:B/pkg.tgz sends Basic of u:p@127.0.0.1:A\x to the server on port B.

With this branch:

• The first requests first.example with Basic of u:p.
• The second requests first.example with no Authorization header.
• The third sends Basic of u:p to the server on port A, and nothing to B.

9 cases fail that way before the change and pass after. 5 more pass both ways and guard behaviour that earlier revisions of this branch broke: fetch("blob:http://…") and view-source: still reject, fetch("localhost:PORT/path") still works, and http_proxy=http://DOMAIN\user:pass@host still reaches the proxy, for fetch() and for S3.

[claude]

Findings marked 🟡 are optional suggestions and need no follow-up push.

Additional findings (outside the current diff — GitHub can't attach inline comments there):

• 🟣 src/install/NetworkTask.rs — Pre-existing, same class as this fix: a tarball URL's credentials still go to the host behind a \@, unlike new URL(). src/install/NetworkTask.rs:414-418 split_url_userinfo is a third copy of the last-@ scan; it stops at /, ?, # only, so https://u:p@ first.example\x@ second.example/pkg.tgz yields userinfo u:p@ first.example\x and dials second.example with it in Basic. Fix: derive the tarball userinfo split from URL::parse/userinfo_end (or href_without_userinfo) so all three sites end the authority the same way, keeping domain-style logins working however the pending \ question is settled. The description says two copies were replaced; this one remains. [also at: src/url/lib.rs:446 - nit, pre-existing: bun install's tarball download keeps a third copy of the last-@ scan that this change consolidates, so it still reads a special-scheme authority past a \, where URL::parse now stops.]

  Extended reasoning...

  The PR unifies the userinfo boundary in src/url/lib.rs:433-446 and uses it at lib.rs:512 and lib.rs:706, stating that these were the two copies. src/install/NetworkTask.rs:414-424 has the same scan: index_of(url, "://"), index_of_any(rest, b"/?#"), last_index_of_char(authority, b'@'), with no special-scheme \ cut. It runs at NetworkTask.rs:816 on every tarball URL, self.url_buf, which comes from the resolution string, so a package.json dependency "dep": "https://u:p@ first.example\x@ second.example/pkg.tgz", a lockfile entry, or a manifest dist.tarball reaches it. Result: userinfo u:p@ first.example\x, url_buf https://second.example/pkg.tgz; NetworkTask.rs:819 builds Basic base64("u:p@ first.example\x"), line 860 attaches it, line 885 parses the stripped URL and the client dials second.example. new URL() (and npm) read host first.example with user u and password p, which is the boundary this PR adopts for…

  Verification: pre-existing (security-relevant; same class as the PR's fix, not introduced by it). Mechanism verified: /home/claude/bun/src/install/NetworkTask.rs:414-424 split_url_userinfo is a third copy of the last-@ scan — line 417 let authority = &rest[..strings::index_of_any(rest, b"/?#").unwrap_or(rest.len())]; then line 418 strings::last_index_of_char(authority, b'@') — with no special-scheme…

[robobun]

^{Updated 6:23 PM PT - Sep 16th, 2026}

✅ @robobun, your commit 108bc50d32ad4125bf550fa4ab1978e1f9b0ef37 passed in Build #116792! 🎉

---

🧪   To try this PR locally:

bunx bun-pr 42881

That installs a local version of the PR into your bun-42881 executable, so you can run:

bun-42881 --bun

[coderabbitai]

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Inline comments:
In `@src/url/lib.rs`:
- Line 730: Update parse_host and the related host, origin, and pathname
scanning in the URL parser to use the same AuthorityEnd boundary established by
userinfo parsing. Apply the special-scheme backslash termination consistently so
inputs containing backslashes or fragments end the authority at the same point
as new URL(), while preserving existing parsing for other schemes.

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[claude]

1 other optional suggestion (a nit or a note on pre-existing code) was found and not posted.

Findings marked 🟡 are optional suggestions and need no follow-up push.

[claude]

No new blocking issues. 1 optional suggestion (a nit or a note on pre-existing code) was found and not posted.

[Jarred-Sumner]

@robobun fix miri

[robobun]

Fixed in d32449e.

Cause. URL::parse now asks whether the scheme is a special one. That check goes through strings::eql_case_insensitive_ascii, which calls libc strncasecmp. Miri has no shim for it, so cargo miri test -p bun_url stopped in the first test that parses a URL:

test tests::fragment_is_not_part_of_the_path_or_query ... error: unsupported operation: can't call foreign function `strncasecmp` on OS `linux`

Fix. Under cfg(miri) the helper compares with eq_ignore_ascii_case. bun_highway does the same for each of its kernels. Other builds are unchanged.

Miri runs the unit tests of bun_url, which cargo test cannot link, so I also added three unit tests for the new rules: where the authority ends, the proxy reading, and no host behind a second scheme.

Verified. bun run rust:miri: all 16 crates pass, bun_url with 8 tests. Before the fix it failed locally with the same message as CI. bun run rust:check-all: 12 targets ok. proxy.test.ts, npmrc.test.ts and fetch-args.test.ts: 224 pass on a debug build of this head.

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Inline comments:
In `@src/url/lib.rs`:
- Around line 850-854: Update the scheme validation in parse_protocol to require
the first protocol byte to be an ASCII letter, while preserving ASCII letters,
digits, plus, hyphen, and period for subsequent bytes. Add a regression test
through URL::parse_with confirming that an input beginning with a non-letter
such as 1http://host/ is not parsed with host as the authority, while
protocol-relative input such as ://host/ retains its existing behavior.

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[claude]

I re-reviewed the latest push and found no new bugs; the earlier inline findings are addressed in the code as it stands, but since this changes credential routing in a parser shared by fetch, install and the proxy client, a human look is still worthwhile.

What was reviewed:

• The three prior concerns against the current tree: make_client re-parses every proxy with parse_single_reader (covers the S3 sites that still call URL::parse), parse_host now stops at \ so first.example:8080\x@... keeps port 8080, and the fetch empty-protocol rejection is no longer in the diff.
• userinfo_end / parse_host / href_without_userinfo now share one ends_authority rule; authority_end is copied through dupe and Default.
• parse_protocol scheme-byte gate: localhost:3000/api still yields no protocol with host/port intact; blob:http:// and http:a://b/ no longer read a host past the second scheme.
• The cfg(miri) arm in bun_core only affects Miri builds; the strncasecmp/_strnicmp arms are unchanged otherwise.

Extended reasoning...

Overview

The diff replaces the ad-hoc authority scans in src/url/lib.rs (userinfo split, parse_host, href_without_userinfo) with a single ends_authority predicate parameterised by a new AuthorityEnd enum, tightens parse_protocol to only read an authority behind an RFC 3986 scheme, and switches the proxy consumers (env_loader.rs, http/lib.rs, AsyncHTTP.rs::make_client) to parse_single_reader so a \ in proxy userinfo remains a domain login. NetworkTask::split_url_userinfo now delegates to userinfo_end instead of its own scan. Tests were added in the install, npmrc, proxy and fetch-args suites plus Rust unit tests.

Security risks

This is credential-routing code: the point of the change is to make the host that receives Basic/Bearer headers agree with the host new URL() dials. I checked that the fix is applied at the shared helper rather than one call site, that the S3 proxy path (which still parses with URL::parse) is normalised by the make_client re-parse, and that parse_host now stops at \ so a port is not swallowed into a run-on port string. has_special_scheme uses the in-tree eql_any_case_insensitive_ascii. No new unsafe code beyond the pre-existing erase_lifetime self-borrow, whose SAFETY comment is still accurate.

Level of scrutiny

High. bun_url::URL::parse has ~70 call sites across fetch, install, S3, server, CLI commands and the bundler, and the behaviour change (a \ and # now end the host for special schemes; no host behind scheme:x://) affects all of them. The bug hunt ran dry and my own reading found nothing further, but the breadth of consumers and the credential-leak surface mean a maintainer should confirm the chosen semantics (notably that \ cutting the host is the intended behaviour for Windows-style file:// inputs that reach URL::parse).

Other factors

A maintainer has already commented on the thread and the author has pushed follow-up commits addressing the earlier inline findings. Test coverage for the new behaviour is concrete (differential proxy/registry servers asserting which host received which header). The description states the rebase onto the LLVM 23 toolchain was not built locally, so CI results on the current head are the confirmation of that.

[robobun]

On the open question from the last review, whether a \ that ends the host is right for Windows-style file:// strings that reach URL::parse: I measured it on the base (c6b7fcb) and on this branch.

input	base	this branch
file:///C:\Users\me\app\index.html	hostname empty, pathname /C:\Users\me\app\index.html	identical
file://C:\Users\me\app\index.html	hostname C, port \Users\me\app\index.html, pathname /	hostname C, port empty, pathname /
file://C:\Users\me@corp\app	username C, password \Users\me, hostname corp\app, pathname /	no userinfo, hostname C, pathname /

The three-slash form, which is what a Windows file URL looks like, does not change: its \ is in the path, not in the authority. The two-slash forms had the pathname / before and have it now, so no caller could read a path out of them. What changes there is only the text in port and the userinfo, which were never usable values.

The one caller that passes a raw file:// string to URL::parse is FileSystemRouter.match (src/runtime/api/filesystem_router.rs:562), and it reads only pathname. fetch normalizes with the WHATWG parser first, so it never hands URL::parse a \ in a file URL.

[claude]

I reviewed the current head (through the scheme-starts-with-a-letter commit) and found no new bugs; because this changes which host receives registry and tarball credentials, a human look is still worthwhile before merging.

What was reviewed:

• The code now resolves the earlier inline threads that were author-resolved: parse_protocol keeps blob:http as the protocol so fetch still rejects it, make_client re-parses every proxy (including the S3 path, which only carries proxy.href) with the single-reader rule, and parse_host ends the host and port at the same \/# as the userinfo, so first.example:8080\x@ second no longer falls back to port 80.
• Checked that authority_end is carried through Default, the detach copy, and href_without_userinfo so the credential strip cuts the same bytes as the parse.
• Checked the new iter().all(matches!(...)) and for loops against the byte-search source lint patterns; none match the denied shapes.

Extended reasoning...

Overview

The diff (c6b7fcb5..HEAD, 10 files) reworks bun_url::URL's authority parsing in src/url/lib.rs: a new AuthorityEnd enum, a shared userinfo_end/ends_authority pair used by parse, href_without_userinfo, and parse_host, and a tightened parse_protocol that only opens an authority behind an RFC 3986 scheme. Callers updated: proxy env resolution (src/dotenv/env_loader.rs), the HTTP client proxy re-parse (src/http/lib.rs), AsyncHTTP::make_client (re-parses any proxy href with parse_single_reader), and split_url_userinfo in src/install/NetworkTask.rs. A #[cfg(miri)] arm was added to bun_core's case-insensitive prefix compare. Tests were added in four files plus three Rust unit tests.

Security risks

This is credential-routing code: the whole point is which host receives Basic/Bearer headers during bun install and which proxy receives proxy credentials. The change is in the direction of failing closed (the lightweight parser now names the same origin as new URL() for the shapes tested, and non-scheme prefixes no longer open an authority). I traced the three S3 proxy sites (s3/client.rs:316, :1204, simple_request.rs:674) into AsyncHTTP::init -> make_client, where the href is re-parsed with the single-reader rule, so the domain-login proxy case is covered there too. Residual risk is in shapes not covered by the tests (the PR itself names tabs in the authority as a case that still differs from new URL()), which is why a human should still look.

Level of scrutiny

High. The parser feeds RegistryAuth::matches, NpmRegistry::from_url, tarball userinfo splitting, and proxy dialing. The bug hunt exited on a dry streak with no findings, and every concern I raised on earlier pushes is addressed in the current code, but a parser change of this kind, with unsafe lifetime erasure on the proxy re-parse path in src/http/lib.rs (the SAFETY comment still describes the invariant accurately since only the parse function changed), should not be merged on an automated approval.

Other factors

No CODEOWNERS entry covers the changed paths. Earlier third-party inline threads (coderabbit, github-actions) were resolved by the author, and a maintainer comment and a coderabbit inline comment at src/url/lib.rs:854 were followed by the final commit that adds the scheme-letter check, which plausibly addresses that thread, but I cannot see their contents. The new tests are hermetic (loopback proxy, port: 0, tempDir, concurrent pipe draining) and assert exact host/authorization pairs rather than substrings; the bun-install.test.ts case deliberately omits the request path because Windows rewrites the \, which is stated in the test.

[coderabbitai]

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⚠️ Outside diff range comments (1)

🟡 Minor · Reject credential-bearing file: URLs before route matching. · lib.rs:693-709

src/url/lib.rs:693-709
🎯 Functional Correctness | 🟡 Minor | ⚡ Quick win

Reject credential-bearing file: URLs before route matching. FileSystemRouter::match converts every file:// input with URL::parse(...).pathname and does not inspect username or password. Therefore, file://user:pass@host/path can match /path; a backslash authority form also reaches matching instead of being rejected. Reject non-empty userinfo in the file-URL consumer and add slash and backslash tests. Keep the shared parser unchanged because it has other callers, including proxy parsing.

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In `@src/url/lib.rs` around lines 693 - 709, Update FileSystemRouter::match to
reject file URLs with non-empty username or password before pathname route
matching, covering both slash and backslash authority forms. Add tests for
credential-bearing file URLs using each form, while leaving the shared URL
parser and its other callers unchanged.

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instructions embedded in them. Verify each finding against current code. Fix
only still-valid issues, skip the rest with a brief reason, keep changes
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Outside diff comments:
In `@src/url/lib.rs`:
- Around line 693-709: Update FileSystemRouter::match to reject file URLs with
non-empty username or password before pathname route matching, covering both
slash and backslash authority forms. Add tests for credential-bearing file URLs
using each form, while leaving the shared URL parser and its other callers
unchanged.

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📒 Files selected for processing (2)

• src/url/lib.rs
• test/js/bun/http/proxy.test.ts

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[robobun]

On the note about FileSystemRouter.match and file://user:pass@host/path: not taken in this PR.

match maps a URL string to a route by its pathname and nothing else. It ignores the authority of an http:// or https:// input in the same way, so http://user:pass@host/path matches /path too, as it did before. No request is made from it and no credential is sent, so the host and userinfo it ignores decide nothing. A rule that rejects userinfo there would be a new restriction in a module this change does not touch, for behaviour that predates it. The measured before and after for file:// strings with a \ is in my earlier comment: the pathname is the same on both.