fix: prefer the default error page when failing to decode the URL pathname by teemingc · Pull Request #15744 · sveltejs/kit

teemingc · 2026-04-22T19:11:33Z

Previously, if a URL pathname could not be decoded, you'd get a text response. This PR makes it so that it renders the default error page instead which is a lot prettier for users. This only affects built apps because the Vite dev server intercepts malformed URIs

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svelte-docs-bot · 2026-04-22T19:16:17Z

Preview: https://svelte-dev-git-preview-kit-15744-svelte.vercel.app/

dummdidumm

While this works, can we somehow rework this so that it returns a proper thing directly, instead of having to set the path to null and then hundreds of lines of code later return an error response?

teemingc · 2026-04-23T07:15:28Z

While this works, can we somehow rework this so that it returns a proper thing directly, instead of having to set the path to null and then hundreds of lines of code later return an error response?

Do you mean directly calling respond_with_error when we fail to decode? I tried that but the issue is I don't think we can get the transformPageChunk, filterSerializedResponseHeaders, preload resolve args until the actual resolve call.

teemingc · 2026-05-21T16:46:40Z

Need to hold off on this until we rewrite server/respond.js

EDIT: Actually, returning handle early might be good enough

teemingc · 2026-05-21T17:23:40Z

 		return await handle_fatal_error(event, event_state, options, e);
 	}

+	async function handle() {


This function was just moved to an outer closure

This PR was opened by the [Changesets release](https://github.com/changesets/action) GitHub action. When you're ready to do a release, you can merge this and the packages will be published to npm automatically. If you're not ready to do a release yet, that's fine, whenever you add more changesets to main, this PR will be updated. # Releases ## @sveltejs/kit@2.61.0 ### Minor Changes - breaking: the `.run()` method has been removed from remote queries on both the client and the server. Use `await query()` directly instead — it now works everywhere ([#15779](#15779)) - feat: remote queries can now be awaited in any context (event handlers, module scope, async callbacks), not just inside reactive contexts. The cache is shared across reactive and non-reactive subscribers, so awaiting a query in an event handler will dedupe with components that have already subscribed to the same query. ([#15779](#15779)) - feat: live query instances are now themselves async-iterable ([#15878](#15878)) - feat: add programmatic `submit` method to `form` remote function instances ([#15657](#15657)) - feat: pass `form` remote function instance into `enhance` callback ([#15657](#15657)) ### Patch Changes - fix: resolve the app payload without using `process.env.NODE_ENV` ([#15852](#15852)) - fix: support `exactOptionalPropertyTypes` for optional route params ([#15825](#15825)) - fix: correctly send `true` value to the server for 'submit' and 'hidden' form fields ([#15858](#15858)) - fix: avoid build warnings about undefined universal hooks ([#15895](#15895)) - fix: prefer default error page when failing to decode the URL pathname ([#15744](#15744)) - fix: disable link prefetching on slow internet connections ([#15885](#15885)) - fix: allow routes ending with optional parameters next to more specific routes ([#15861](#15861)) - fix: remove reliance on Content-Length header in deserialize_binary_form, which caused failures when proxies (e.g. Vercel, Azure) strip the header and use chunked transfer encoding ([#15796](#15796)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

closes #14896 The `router.resolution` docs say the server "has an opportunity to intercept each navigation (for example through a middleware)". #14896 read that as "the `handle` hook runs", which it does not. Route resolution requests are answered as soon as the route has been looked up ([respond.js#L323-L324](https://github.com/sveltejs/kit/blob/1406668dbc9c18928dabeff9d15ec756d6d455b3/packages/kit/src/runtime/server/respond.js#L323-L324)), before `handle` is invoked and after `reroute` has run ([respond.js#L249](https://github.com/sveltejs/kit/blob/1406668dbc9c18928dabeff9d15ec756d6d455b3/packages/kit/src/runtime/server/respond.js#L249)). Verified empirically in dev and in preview after a production build, details in #14896 (comment). The wording dates to #13379, which introduced server-side route resolution. The new sentence is scoped to the route lookup rather than stating a blanket "handle never runs", because there is one path where it does. A pathname that fails to decode falls through to normal request handling ([respond.js#L272-L277](https://github.com/sveltejs/kit/blob/1406668dbc9c18928dabeff9d15ec756d6d455b3/packages/kit/src/runtime/server/respond.js#L272-L277)), deliberate behavior from #15744 so that malformed URLs render the default error page. In production `GET /%c0/__route.js` therefore reaches `handle` with pathname `/%c0` before being rejected with a 400. Dev masks this because the dev middleware rejects malformed URIs earlier, which #15744 also notes. Two changes to the option's JSDoc. "Middleware" now says what it refers to, and a sentence states which hooks run for resolution requests. `types/index.d.ts` regenerated. Note on sequencing, #16396 also touches `public.d.ts` (different lines) and regenerates `types/index.d.ts`; whichever merges second needs a trivial rebase and regeneration. --- ### Please don't delete this checklist! Before submitting the PR, please make sure you do the following: - [x] It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs - [x] This message body should clearly illustrate what problems it solves. - [x] Ideally, include a test that fails without this PR but passes with it. ### Tests - [x] Run the tests with `pnpm test` and lint the project with `pnpm lint` and `pnpm check` ### Changesets - [x] If your PR makes a change that should be noted in one or more packages' changelogs, generate a changeset by running `pnpm changeset` and following the prompts. Changesets that add features should be `minor` and those that fix bugs should be `patch`. Please prefix changeset messages with `feat:`, `fix:`, or `chore:`. ### Edits - [x] Please ensure that 'Allow edits from maintainers' is checked. PRs without this option may be closed. --------- Co-authored-by: Nic Polumeyv <nicolas.polum@gmail.com>

teemingc added 2 commits April 23, 2026 03:08

prefer default error page when failing to decode the uri pathname

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dummdidumm reviewed Apr 22, 2026

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teemingc requested a review from dummdidumm May 18, 2026 21:34

teemingc marked this pull request as draft May 21, 2026 16:46

teemingc added 3 commits May 22, 2026 00:47

Merge branch 'main' into decode-uri-error-page

a1ebfc4

try this

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move this back

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teemingc marked this pull request as ready for review May 21, 2026 17:21

teemingc commented May 21, 2026

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dummdidumm approved these changes May 21, 2026

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teemingc merged commit 69b5787 into main May 21, 2026
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teemingc deleted the decode-uri-error-page branch May 21, 2026 19:04

This was referenced May 21, 2026

Version Packages #15853

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Version Packages (next) #15311

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Nic-Polumeyv mentioned this pull request Jul 17, 2026

docs: clarify which hooks run during server route resolution #16397

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fix: prefer the default error page when failing to decode the URL pathname - #15744

fix: prefer the default error page when failing to decode the URL pathname#15744
teemingc merged 5 commits into
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