Astro 6: Build crashes with [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".svelte" #15856
Description
Astro Info
Astro v6.0.3
Node v24.14.0
System Windows (x64)
Package Manager pnpm
Output static
Adapter none
Integrations @astrojs/svelte
If this issue only occurs in one browser, which browser is a problem?
N/A
Describe the Bug
After updating to Astro 6, my build crashes on bits-ui dependency with error:
generating static routes
12:56:16 ├─ /index.html12:56:16 [ERROR] TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".svelte" for C:\dev\issue-astro-svelte-bits-ui\node_modules\.pnpm\bits-ui@2.16.3_@internationalized+date@3.12.0_svelte@5.53.10\node_modules\bits-ui\dist\bits\accordion\components\accordion.svelte
at Object.getFileProtocolModuleFormat [as file:] (node:internal/modules/esm/get_format:185:9)
at defaultGetFormat (node:internal/modules/esm/get_format:211:36)
at defaultLoadSync (node:internal/modules/esm/load:158:16)
at #loadAndMaybeBlockOnLoaderThread (node:internal/modules/esm/loader:796:12)
at #loadSync (node:internal/modules/esm/loader:816:49)
at ModuleLoader.load (node:internal/modules/esm/loader:781:26)
at ModuleLoader.loadAndTranslate (node:internal/modules/esm/loader:526:31)
at #getOrCreateModuleJobAfterResolve (node:internal/modules/esm/loader:577:36)
at afterResolve (node:internal/modules/esm/loader:625:52)
at ModuleLoader.getOrCreateModuleJob (node:internal/modules/esm/loader:631:12)
12:56:16 [ERROR] [build] Caught error rendering /: TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".svelte" for C:\dev\issue-astro-svelte-bits-ui\node_modules\.pnpm\bits-ui@2.16.3_@internationalized+date@3.12.0_svelte@5.53.10\node_modules\bits-ui\dist\bits\accordion\components\accordion.svelte
Unknown file extension ".svelte" for C:\dev\issue-astro-svelte-bits-ui\node_modules\.pnpm\bits-ui@2.16.3_@internationalized+date@3.12.0_svelte@5.53.10\node_modules\bits-ui\dist\bits\accordion\components\accordion.svelte
Hint:
You likely need to add this package to `vite.ssr.noExternal` in your astro config file.
Stack trace:
at Object.getFileProtocolModuleFormat [as file:] (node:internal/modules/esm/get_format:185:9)
at defaultLoadSync (node:internal/modules/esm/load:158:16)
at #loadSync (node:internal/modules/esm/loader:816:49)
at ModuleLoader.loadAndTranslate (node:internal/modules/esm/loader:526:31)
at afterResolve (node:internal/modules/esm/loader:625:52)
ELIFECYCLE Command failed with exit code 1.
Adding it to noExternal, as suggested in the log, does not fix the issue.
// astro.config.mjs
vite: {
ssr: {
noExternal: ['bits-ui']
}
},What's the expected result?
Build not crashing
Link to Minimal Reproducible Example
https://github.com/phenomen/issue-astro-svelte-bits-ui
Participation
- I am willing to submit a pull request for this issue.