[TastyHeadphones]

fetch(123), fetch(undefined), and fetch({ toString() { return "/some_path" } }) all failed with "URL must not be a blank string" even when the input wasn't blank.

When href_from_js can't build a URL, we now stringify the input (unless it's a RequestInit with a url property) so validation can say the URL is invalid. Host-less http(s)/s3 URLs get "must have a hostname" instead.

Fixes #21361

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Reviewing files that changed from the base of the PR and between ca41503 and 08c2ca7.

📒 Files selected for processing (2)

• src/runtime/webcore/fetch.rs
• test/js/web/fetch/fetch-args.test.ts

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Walkthrough

The fetch implementation now stringifies eligible non-string inputs, rejects remote URLs without hostnames, and updates the preconnect error. Tests cover invalid numeric, undefined, and relative stringified inputs.

Changes

Fetch URL validation

Layer / File(s)	Summary
URL conversion and hostname validation src/runtime/webcore/fetch.rs, test/js/web/fetch/fetch-args.test.ts	StringOrURL::from_js stringifies eligible values. fetch() and fetch.preconnect() reject remote URLs without hostnames with updated errors. Tests cover additional invalid inputs.

Suggested reviewers: robobun

Priority: ⬇️ Low

Severity of issue fixed: Low

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: clearer fetch errors for non-string and host-less URLs.
Description check	✅ Passed	The description explains the fetch error-handling changes and references the linked issue. It does not include the template heading or details for how the changes were verified, but the main purpose a…
Linked Issues check	✅ Passed	The changes address [#21361]. StringOrURL::from_js stringifies non-string values that are not RequestInit objects with a url property. This covers undefined, numbers, and objects whose `toStri…
Out of Scope Changes check	✅ Passed	The changed source code and tests support [#21361]. The RequestInit exception preserves the existing request-init path, and the preconnect hostname validation keeps the same URL validation behavior.…

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