Snippet export causes `dev` script to fail

[jerrythomas]

Describe the bug

bun run dev

$ vite dev
5:10:38 PM [vite] (client) Forced re-optimization of dependencies

  VITE v6.1.1  ready in 250 ms

  ➜  Local:   http://localhost:5173/
  ➜  Network: use --host to expose
  ➜  press h + enter to show help
Error:   Failed to scan for dependencies from entries:
  /Users/Jerry/Developer/Labs/sk-snippet/src/routes/+page.svelte

  ✘ [ERROR] "listItems" is not declared in this file

    script:/Users/Jerry/Developer/Labs/sk-snippet/src/lib/ListItems.svelte?id=0:2:11:
      2 │   export { listItems };
        ╵            ~~~~~~~~~


    at failureErrorWithLog (/Users/Jerry/Developer/Labs/sk-snippet/node_modules/esbuild/lib/main.js:1476:15)
    at /Users/Jerry/Developer/Labs/sk-snippet/node_modules/esbuild/lib/main.js:945:25
    at runOnEndCallbacks (/Users/Jerry/Developer/Labs/sk-snippet/node_modules/esbuild/lib/main.js:1316:45)
    at buildResponseToResult (/Users/Jerry/Developer/Labs/sk-snippet/node_modules/esbuild/lib/main.js:943:7)
    at /Users/Jerry/Developer/Labs/sk-snippet/node_modules/esbuild/lib/main.js:955:9
    at new Promise (<anonymous>)
    at requestCallbacks.on-end (/Users/Jerry/Developer/Labs/sk-snippet/node_modules/esbuild/lib/main.js:954:54)
    at handleRequest (/Users/Jerry/Developer/Labs/sk-snippet/node_modules/esbuild/lib/main.js:647:17)
    at handleIncomingPacket (/Users/Jerry/Developer/Labs/sk-snippet/node_modules/esbuild/lib/main.js:672:7)
    at Socket.readFromStdout (/Users/Jerry/Developer/Labs/sk-snippet/node_modules/esbuild/lib/main.js:600:7)

bun run build
$ vite build
vite v6.1.1 building SSR bundle for production...
✓ 158 modules transformed.
vite v6.1.1 building for production...
✓ 135 modules transformed.
.svelte-kit/output/client/_app/version.json                        0.03 kB │ gzip:  0.05 kB
.svelte-kit/output/client/.vite/manifest.json                      2.91 kB │ gzip:  0.56 kB
.svelte-kit/output/client/_app/immutable/chunks/D0gPaxp9.js        0.03 kB │ gzip:  0.05 kB
.svelte-kit/output/client/_app/immutable/entry/start.CfSTwjUw.js   0.06 kB │ gzip:  0.08 kB
.svelte-kit/output/client/_app/immutable/chunks/DyqcDmWL.js        0.32 kB │ gzip:  0.25 kB
.svelte-kit/output/client/_app/immutable/nodes/0.e8bPOg00.js       0.33 kB │ gzip:  0.24 kB
.svelte-kit/output/client/_app/immutable/chunks/CEAgSoVa.js        0.99 kB │ gzip:  0.56 kB
.svelte-kit/output/client/_app/immutable/nodes/1.BBLo2Zc1.js       1.06 kB │ gzip:  0.61 kB
.svelte-kit/output/client/_app/immutable/chunks/SWgnAoEH.js        2.48 kB │ gzip:  1.36 kB
.svelte-kit/output/client/_app/immutable/chunks/BgrhOOmg.js        3.10 kB │ gzip:  1.47 kB
.svelte-kit/output/client/_app/immutable/nodes/2.BDqgpbH2.js       3.18 kB │ gzip:  1.65 kB
.svelte-kit/output/client/_app/immutable/entry/app.BQLo7ahP.js     6.34 kB │ gzip:  2.98 kB
.svelte-kit/output/client/_app/immutable/chunks/B4LphI0t.js       12.57 kB │ gzip:  5.18 kB
.svelte-kit/output/client/_app/immutable/chunks/CRa4OZW5.js       32.03 kB │ gzip: 12.48 kB
✓ built in 166ms
.svelte-kit/output/server/.vite/manifest.json                   1.93 kB
.svelte-kit/output/server/entries/fallbacks/layout.svelte.js    0.17 kB
.svelte-kit/output/server/internal.js                           0.31 kB
.svelte-kit/output/server/chunks/escaping.js                    0.48 kB
.svelte-kit/output/server/chunks/equality.js                    0.67 kB
.svelte-kit/output/server/entries/pages/_page.svelte.js         0.81 kB
.svelte-kit/output/server/entries/fallbacks/error.svelte.js     1.52 kB
.svelte-kit/output/server/chunks/index.js                       3.06 kB
.svelte-kit/output/server/chunks/exports.js                     6.89 kB
.svelte-kit/output/server/chunks/internal.js                   42.79 kB
.svelte-kit/output/server/index.js                            100.35 kB
✓ built in 465ms

Run npm run preview to preview your production build locally.

> Using @sveltejs/adapter-auto
  Could not detect a supported production environment. See https://svelte.dev/docs/kit/adapters to learn how to configure your app to run on the platform of your choosing
  ✔ done

A subsequent bun run dev works.

Reproduction

How to replicate

git clone git@github.com:jerrythomas/issue-sk-snippet.git
bun i
bun run dev

Playground

The same code works on the playground

https://svelte.dev/playground/9f2ce709c92c451c98221568e8aeaf4e?version=5.20.2

Build works

This runs without errors too!

bun i
bun run build

Logs

System Info

System:
    OS: macOS 15.3.1
    CPU: (16) arm64 Apple M4 Max
    Memory: 614.81 MB / 48.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 23.4.0 - ~/.nvm/versions/node/v23.4.0/bin/node
    npm: 10.9.2 - ~/.nvm/versions/node/v23.4.0/bin/npm
    pnpm: 10.3.0 - /opt/homebrew/bin/pnpm
    bun: 1.2.2 - /opt/homebrew/bin/bun
  Browsers:
    Chrome: 133.0.6943.126
    Safari: 18.3
  npmPackages:
    svelte: ^5.0.0 => 5.20.2

Severity

annoyance

[jerrythomas]

Even though in the reproduction, bun run dev works after the bun run build. However, in my repository I had the snippet in a separate library, and in that repo, bun run build did not solve the bun run dev issue.

I will try to see if I can reproduce the scenario.

[Conduitry]

Does the issue appear with Node? If so, please provide a reproduction using that. Bun has a lot of issues due to incomplete/buggy Node compatibility.

[jerrythomas]

yes. pnpm dev also has the same issue. The problem arises when the snippet is used in a package and the component that uses the snippet is imported and used in a svelte-kit app.

pnpm dev

> sk-snippet@0.0.1 dev /Users/Jerry/Developer/Labs/sk-snippet/sites/sample
> vite dev

1:46:11 PM [vite] (client) Re-optimizing dependencies because lockfile has changed

  VITE v6.2.1  ready in 255 ms

  ➜  Local:   http://localhost:5173/
  ➜  Network: use --host to expose
  ➜  press h + enter to show help
Error:   Failed to scan for dependencies from entries:
  /Users/Jerry/Developer/Labs/sk-snippet/sites/sample/src/routes/+page.svelte

  ✘ [ERROR] "listItems" is not declared in this file

    script:/Users/Jerry/Developer/Labs/sk-snippet/packages/src/ListItems.svelte?id=0:2:11:
      2 │   export { listItems };
        ╵            ~~~~~~~~~

The repository has been updated.
snippet in workspace

Steps to reproduce

git clone git@github.com:jerrythomas/issue-sk-snippet.git
pnpm i
cd sites/sample
pnpm build
pnpm dev

[afreidz]

I can confirm that the same is happening for an astro project and not just sk. when vite tries to resolve the snippet export in a file that imports it, the dev server spits out these errors. however, the snippet seems to import and work correctly both in build and in dev server. but for me it seems like the dev server is noticeably slower since these errors started to occur.

[jan-bartunek-myriad]

I can confirm the same problem in our SvelteKit project with Node and pnpm.

Details

❯ pnpm -v 
10.8.0

❯ node -v
v22.14.0

Package versions:

"svelte": "^5.27.0",
"@sveltejs/kit": "^2.20.7",
"vite": "^6.3.0",

[phocks]

Same here in a SvekteKit project with Node and npm

 [ERROR] "transition" is not declared in this file

    script:/[.....]/Default.svelte?id=0:2:11:
      2 │   export { transition, overlay, zoom };

[urboifox]

Any updated on this?
I got the same issue with Sveltekit & Bun

"vite": "^6.3.5",
"svelte": "^5.33.14",
"@sveltejs/kit": "^2.21.2"

[phocks]

This is still not fixed for me, but I managed to get around it. Instead of exporting the snippets themselves, I put the snippets into their own separate component, and then imported that component into my 2 separate other components where needed.

I'm not sure this will be a solution in all cases where you actually need to export the snippets themselves, but for me I was able to just export a shared component with the snippets encapsulated inside it.