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error called within load functions trigger a "preloading data error" #15425
Description
Describe the bug
When triggering a 404 in a load function (in my case, from the server), I correctly get a 404 page. However, 2 unexpected things happen:
- I get a "Preloading data for failed" warning
- my
handleErrorclient hook (not server) receives a 500 error
Errors or redirects manually and intentionally sent should not be considered as preloading errors, and only gracefully serve the desired error page
Reproduction
Click the "About" tab after opening the browser's console
Logs
// when logging \`${JSON.stringify({ error, status, event, message })}\` in my `handleError`
{
"error": {
"type": "error",
"error": {
... // second arg of my `error(404, { ... })` call
},
"status": 404 // accurate
},
"status": 500, // unexpected
"event": {
"params": { ... },
"url": "...",
"route": {
"id": "..."
}
},
"message": "Internal Error" // unexpected
}
---
// the other warning I get at the same time
Preloading data for /pull/vercel/nft/568 failed with the following error: Internal Error
If this error is transient, you can ignore it. Otherwise, consider disabling preloading for this route. This route was preloaded due to a data-sveltekit-preload-data attribute. See https://svelte.dev/docs/kit/link-options for more infoSystem Info
System:
OS: macOS 26.3
CPU: (10) arm64 Apple M1 Pro
Memory: 1.42 GB / 16.00 GB
Shell: 5.9 - /bin/zsh
Binaries:
Node: 25.6.1 - /opt/homebrew/bin/node
npm: 11.10.1 - /opt/homebrew/bin/npm
pnpm: 10.30.1 - /opt/homebrew/bin/pnpm
bun: 1.3.9 - /Users/antoine/.bun/bin/bun
Deno: 2.6.10 - /opt/homebrew/bin/deno
Browsers:
Chrome: 137.0.7151.120
Firefox: 145.0.1
Safari: 26.3
Safari Technology Preview: 26.0
npmPackages:
@sveltejs/adapter-vercel: ^6.3.2 => 6.3.2
@sveltejs/kit: ^2.53.0 => 2.53.0
svelte: ^5.53.1 => 5.53.1
vite: ^7.3.1 => 7.3.1Severity
annoyance
Additional Information
No response
Activity
fix(analytics): prevent intentional errors from triggering error hooks
Nic-Polumeyv commentedon Aug 12, 2026
Fixed on version-3. Since #12579 the client handleError hook is skipped for server load errors, and universal load errors reach it with their real status. Same bug as #16456, where a 2.x backport was declined. The dev warning still fires, now with the real message.