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fix: correct relative paths on error page for a missing __data.json request - #15884

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ATOM00blue:fix-data-suffix-relative-paths
Jun 16, 2026
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fix: correct relative paths on error page for a missing __data.json request#15884
Rich-Harris merged 3 commits into
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ATOM00blue:fix-data-suffix-relative-paths

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closes #11353

When a non-existent page is requested with the __data.json suffix (e.g. /example/__data.json), the suffix is stripped from the URL before routing so that the path can be matched against the route table. The error page that is rendered for the resulting 404 then computed its relative asset paths from that stripped URL, which is one path segment shallower than the URL the browser is actually at. As a result the _app/immutable/... links (and the resolve/asset helpers from $app/paths) ended up one directory too shallow, so the error page loaded unstyled and without its scripts.

For example, requesting /example/__data.json produced asset links that resolved to /example/_app/... instead of /_app/....

This re-adds the data suffix when computing the relative path depth in both the error page renderer and $app/paths' resolve/asset, so the paths are resolved against the URL the browser is actually at. Root-level requests (/__data.json) and the .html__data.json form are unaffected because the reconstructed path has the same segment depth as the original request.


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…ssing __data.json request

When a non-existent page is requested with the `__data.json` suffix, the
suffix is stripped from the URL before routing. The error page that gets
rendered computed its relative asset paths from that stripped URL, so the
paths ended up one directory too shallow and failed to load the app's
assets in the browser.

Account for the data suffix when computing the relative path depth in both
the error page renderer and `$app/paths`' `resolve`/`asset`, so the paths
are resolved against the URL the browser is actually at.
Copilot AI review requested due to automatic review settings May 22, 2026 03:00
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🦋 Changeset detected

Latest commit: 56d75d3

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package
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@sveltejs/kit Patch

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thank you!

@Rich-Harris
Rich-Harris merged commit 961ba01 into sveltejs:main Jun 16, 2026
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@github-actions github-actions Bot mentioned this pull request Jun 16, 2026
Rich-Harris pushed a commit that referenced this pull request Jun 18, 2026
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/enhanced-img@0.11.0

### Minor Changes


- feat: export `EnhancedImgAttributes` type
([#15649](#15649))


### Patch Changes


- fix: exclude imports with `?` character from transformation
([#15617](#15617))
## @sveltejs/kit@2.66.0

### Minor Changes


- feat: precompress prerendered `.md` and `.mdx` files
([#15893](#15893))


- feat: warn the user when they forget to make boolean inputs optional
in their form schemas
([#15804](#15804))


### Patch Changes


- fix: blur active element before component update during navigation so
that blur/focusout handlers fire while old component data is still valid
([#15452](#15452))


- fix: ensure `base` is available from `$service-worker` during
development ([#15882](#15882))


- fix: use correct relative asset paths when rendering an error page for
a missing `__data.json` request
([#15884](#15884))


- fix: preserve active `for await` consumers across `query.live`
reconnects ([#16022](#16022))


- fix: settle `query.live` reconnect promise on all exit paths,
preventing `invalidateAll()` from deadlocking when a live query is
offline or interrupted
([#16022](#16022))


- fix: preserve last value when a `query.live` stream completes without
yielding on reconnect
([#16022](#16022))


- fix: remove `types: ['node']` from generated tsconfig to avoid errors
when `@types/node` is not installed
([#15709](#15709))


- fix: prefer pages over endpoints when prerendering
([#16076](#16076))


- fix: restore snapshots after afterNavigate callbacks
([#16066](#16066))


- fix: support `ws:`/`wss:` and `trusted-types-eval` for CSP sources
([#15938](#15938))


- fix: omit empty `file` inputs from remote form data
([#15898](#15898))


- fix: fail early if a route with `+page` and `+server` is marked as
prerenderable ([#16075](#16075))


- fix: wait a tick before resetting forms
([#15805](#15805))


- fix: `preflight` schemas apply correctly when chained before `for`
([#15863](#15863))


- fix: blank page in SPA mode when root layout `load()` throws
([#15798](#15798))


- fix: pass all unknown options from the `sveltekit` Vite plugin through
to `vite-plugin-svelte`
([#16010](#16010))
## @sveltejs/adapter-node@5.5.5

### Patch Changes


- fix: bundle entrypoints alongside app code
([#16069](#16069))


- fix: log the actual adapter-node listening address
([#15899](#15899))

- Updated dependencies
[[`63f1b0b`](63f1b0b),
[`1dbff3f`](1dbff3f),
[`961ba01`](961ba01),
[`d2e108c`](d2e108c),
[`d2e108c`](d2e108c),
[`d2e108c`](d2e108c),
[`860b3c7`](860b3c7),
[`f8c842c`](f8c842c),
[`d3aa5fe`](d3aa5fe),
[`0dd7659`](0dd7659),
[`03e9f66`](03e9f66),
[`57b7b7b`](57b7b7b),
[`4eabadc`](4eabadc),
[`6fbf2b6`](6fbf2b6),
[`276744d`](276744d),
[`8740132`](8740132),
[`f430a68`](f430a68),
[`1c7a8dc`](1c7a8dc)]:
  - @sveltejs/kit@2.66.0
## @sveltejs/adapter-vercel@6.3.4

### Patch Changes


- fix: prevent missing immutable assets from being cached as 404s for a
year ([#16077](#16077))

- Updated dependencies
[[`63f1b0b`](63f1b0b),
[`1dbff3f`](1dbff3f),
[`961ba01`](961ba01),
[`d2e108c`](d2e108c),
[`d2e108c`](d2e108c),
[`d2e108c`](d2e108c),
[`860b3c7`](860b3c7),
[`f8c842c`](f8c842c),
[`d3aa5fe`](d3aa5fe),
[`0dd7659`](0dd7659),
[`03e9f66`](03e9f66),
[`57b7b7b`](57b7b7b),
[`4eabadc`](4eabadc),
[`6fbf2b6`](6fbf2b6),
[`276744d`](276744d),
[`8740132`](8740132),
[`f430a68`](f430a68),
[`1c7a8dc`](1c7a8dc)]:
  - @sveltejs/kit@2.66.0

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
huskas-2189 pushed a commit to huskas-2189/Bookmark that referenced this pull request Jun 20, 2026
This PR contains the following updates:

| Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) |
|---|---|---|---|
| [@sveltejs/kit](https://svelte.dev) ([source](https://github.com/sveltejs/kit/tree/HEAD/packages/kit)) | [`2.65.1` → `2.66.0`](https://renovatebot.com/diffs/npm/@sveltejs%2fkit/2.65.1/2.66.0) | ![age](https://developer.mend.io/api/mc/badges/age/npm/@sveltejs%2fkit/2.66.0?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/npm/@sveltejs%2fkit/2.65.1/2.66.0?slim=true) |

---

### Release Notes

<details>
<summary>sveltejs/kit (@&#8203;sveltejs/kit)</summary>

### [`v2.66.0`](https://github.com/sveltejs/kit/blob/HEAD/packages/kit/CHANGELOG.md#2660)

[Compare Source](https://github.com/sveltejs/kit/compare/@sveltejs/kit@2.65.2...@sveltejs/kit@2.66.0)

##### Minor Changes

- feat: precompress prerendered `.md` and `.mdx` files ([#&#8203;15893](sveltejs/kit#15893))

- feat: warn the user when they forget to make boolean inputs optional in their form schemas ([#&#8203;15804](sveltejs/kit#15804))

##### Patch Changes

- fix: blur active element before component update during navigation so that blur/focusout handlers fire while old component data is still valid ([#&#8203;15452](sveltejs/kit#15452))

- fix: ensure `base` is available from `$service-worker` during development ([#&#8203;15882](sveltejs/kit#15882))

- fix: use correct relative asset paths when rendering an error page for a missing `__data.json` request ([#&#8203;15884](sveltejs/kit#15884))

- fix: preserve active `for await` consumers across `query.live` reconnects ([#&#8203;16022](sveltejs/kit#16022))

- fix: settle `query.live` reconnect promise on all exit paths, preventing `invalidateAll()` from deadlocking when a live query is offline or interrupted ([#&#8203;16022](sveltejs/kit#16022))

- fix: preserve last value when a `query.live` stream completes without yielding on reconnect ([#&#8203;16022](sveltejs/kit#16022))

- fix: remove `types: ['node']` from generated tsconfig to avoid errors when `@types/node` is not installed ([#&#8203;15709](sveltejs/kit#15709))

- fix: prefer pages over endpoints when prerendering ([#&#8203;16076](sveltejs/kit#16076))

- fix: restore snapshots after afterNavigate callbacks ([#&#8203;16066](sveltejs/kit#16066))

- fix: support `ws:`/`wss:` and `trusted-types-eval` for CSP sources ([#&#8203;15938](sveltejs/kit#15938))

- fix: omit empty `file` inputs from remote form data ([#&#8203;15898](sveltejs/kit#15898))

- fix: fail early if a route with `+page` and `+server` is marked as prerenderable ([#&#8203;16075](sveltejs/kit#16075))

- fix: wait a tick before resetting forms ([#&#8203;15805](sveltejs/kit#15805))

- fix: `preflight` schemas apply correctly when chained before `for` ([#&#8203;15863](sveltejs/kit#15863))

- fix: blank page in SPA mode when root layout `load()` throws ([#&#8203;15798](sveltejs/kit#15798))

- fix: pass all unknown options from the `sveltekit` Vite plugin through to `vite-plugin-svelte` ([#&#8203;16010](sveltejs/kit#16010))

### [`v2.65.2`](https://github.com/sveltejs/kit/blob/HEAD/packages/kit/CHANGELOG.md#2652)

[Compare Source](https://github.com/sveltejs/kit/compare/@sveltejs/kit@2.65.1...@sveltejs/kit@2.65.2)

##### Patch Changes

- fix: throw an error when prerendering a root +server.js that returns a non-HTML response ([#&#8203;15994](sveltejs/kit#15994))

- fix: decode base64-serialized fetch bodies before caching them for client-side replay ([#&#8203;16034](sveltejs/kit#16034))

- fix: correctly access explicit dynamic public environment variables from prerendered pages and service workers ([#&#8203;16024](sveltejs/kit#16024))

- fix: allow `preloadCode` to be called during initial page load ([#&#8203;16028](sveltejs/kit#16028))

- fix: send `cache-control: private, no-store` on remote function responses so personalized query results can never be cached by shared caches ([#&#8203;16020](sveltejs/kit#16020))

- fix: preserve the HTTP status and error body when a remote function request fails in transport (e.g. a 401/403 from a `handle` hook), instead of reporting a generic 500 ([#&#8203;16021](sveltejs/kit#16021))

- fix: avoid loading universal nodes during build analysis when the app uses a hash router ([#&#8203;16042](sveltejs/kit#16042))

- fix: correctly serve client entry during development when using the pnpm global virtual store ([#&#8203;16045](sveltejs/kit#16045))

- fix: normalize path separators when comparing config ([#&#8203;16037](sveltejs/kit#16037))

- fix: ensure `building` resolves correctly to allow avoiding build-time explicit environment variable validation ([#&#8203;16058](sveltejs/kit#16058))

- fix: prevent unhandled promise rejections when remote function failures are consumed via `current`/`error` instead of `await` ([#&#8203;16018](sveltejs/kit#16018))

</details>

---

### Configuration

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---

This PR has been generated by [Mend Renovate](https://github.com/renovatebot/renovate).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0My4yMjAuMCIsInVwZGF0ZWRJblZlciI6IjQzLjIyMC4wIiwidGFyZ2V0QnJhbmNoIjoiZGV2ZWxvcCIsImxhYmVscyI6W119-->

Reviewed-on: https://codeberg.org/huskas-2189/Bookmark/pulls/126
Rich-Harris pushed a commit that referenced this pull request Aug 18, 2026
…on-existent routes (#16376)

closes #12910

When the client renders an error page for a URL that matches no route,
the root layout's server data goes missing. The universal `+layout.ts`
load receives `data: null` even though the server runs that exact load
function to render the HTML 404. Reported with `ssr = false`, but any
client-side navigation to a non-existent route hits it.

```
GET /this-route-does-not-exist/__data.json?x-sveltekit-invalidated=1

before  404 text/html          (the rendered error page)
after   200 application/json   {"type":"data","nodes":[{"type":"data","data":[{"rootlayout":1},"rootlayout"],"uses":{}}]}
```

`load_root_error_page` fetches `__data.json` when the root layout has a
server load, sending `x-sveltekit-invalidated=1` for the single root
node. The server matches no route and falls through to the `state.depth
=== 0` branch in `respond.js`, which renders the HTML error page. That
branch predates data requests, so they were never special-cased there,
and the render runs the root layout server load only to discard the
result as HTML. Client-side `load_data` then throws `HttpError(404)`,
which since #16135 is deliberately swallowed to avoid a reload loop,
leaving `server_data_node` null.

teemingc diagnosed this on the issue and named two acceptable outcomes,
"We need to be able to return layout data for an error page although a
route doesn't exist or just return the fallback error page." This PR
implements the first, server side only. The client already consumes the
response, and the fallback option would discard data the server computes
anyway while rendering the HTML 404. No client changes.

The new branch only fires for `is_data_request &&
invalidated_data_nodes?.length === 1`. The invalidation parameter marks
kit's own `load_data` fetches, so a browser navigating directly to a
`.../__data.json` URL keeps getting the HTML error page that #15884
deliberately improved (its options-2 test still passes). Length 1 is
exactly the shape `load_root_error_page` sends, so an old deployed
client requesting multi-node data for a route that no longer exists on
the new server keeps today's 404 instead of receiving a truncated nodes
array. Prerendering is excluded so a missing path still reports 404 for
dead-link detection.

The response reuses `render_data` with a synthetic root page (`layouts:
[], leaf: 0`), so load execution, serialization, streaming, redirect and
error nodes all behave as they do for matched routes. Its `route` JSDoc
is narrowed to the two fields it reads instead of casting the synthetic
object to a full `SSRRoute`. Static hosts are unaffected, there is no
server to return the data, and #16135 already keeps the fallback page
from looping there.

The new test in the basics `Errors` describe asserts both halves, JSON
with the parameter and HTML 404 without it. Fails on `version-3` without
the `respond.js` change.

Sibling PR #16380 touches the client half of this flow (reusing fresh
root layout data instead of refetching). The two compose, whichever
lands second rebases trivially.

---

### 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>
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Non-existent __data.json pages link to broken relative paths

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