while build newer SvelteKit runs the init: ServerInit function from hooks.server.ts

[1muen]

Describe the bug

I noticed the builds failing because on our CI server we dont have the environment variables we check for in our init: ServerInit function.
Earlier versions like "@sveltejs/kit": "2.26.1", dont have that bug.

Reproduction

https://github.com/1muen/sv-build-bug-example/tree/buildFails

Logs

❯ pnpm run build

> sv-bug-example@0.0.1 build /home/lmuen/github/sv-bug-example
> vite build

vite v7.1.3 building SSR bundle for production...
✓ 175 modules transformed.
vite v7.1.3 building for production...
✓ 142 modules transformed.
.svelte-kit/output/client/_app/version.json                        0.03 kB │ gzip:  0.05 kB
.svelte-kit/output/client/.vite/manifest.json                      2.66 kB │ gzip:  0.53 kB
.svelte-kit/output/client/_app/immutable/chunks/Cn8smvWX.js        0.04 kB │ gzip:  0.06 kB
.svelte-kit/output/client/_app/immutable/chunks/DsnmJJEf.js        0.07 kB │ gzip:  0.08 kB
.svelte-kit/output/client/_app/immutable/entry/start.qYLW-IHu.js   0.08 kB │ gzip:  0.09 kB
.svelte-kit/output/client/_app/immutable/nodes/0.D3vBsTvv.js       0.21 kB │ gzip:  0.17 kB
.svelte-kit/output/client/_app/immutable/nodes/2.BpvxDwus.js       0.32 kB │ gzip:  0.24 kB
.svelte-kit/output/client/_app/immutable/chunks/CWdd3wXn.js        0.41 kB │ gzip:  0.29 kB
.svelte-kit/output/client/_app/immutable/nodes/1.BQ1_4Lna.js       1.01 kB │ gzip:  0.58 kB
.svelte-kit/output/client/_app/immutable/chunks/99wAdZLI.js        3.78 kB │ gzip:  2.01 kB
.svelte-kit/output/client/_app/immutable/entry/app.14EI74m7.js     7.30 kB │ gzip:  3.46 kB
.svelte-kit/output/client/_app/immutable/chunks/Dv8ZI-4E.js       20.30 kB │ gzip:  8.08 kB
.svelte-kit/output/client/_app/immutable/chunks/CS2OvKfn.js       31.91 kB │ gzip: 12.52 kB
✓ built in 495ms
✗ Build failed in 1.52s
error during build:
[vite-plugin-sveltekit-compile] Failed with code 1
    at Worker.<anonymous> (file:///home/lmuen/github/sv-bug-example/node_modules/@sveltejs/kit/src/utils/fork.js:65:13)
    at Worker.emit (node:events:518:28)
    at [kOnExit] (node:internal/worker:315:10)
    at Worker.<computed>.onexit (node:internal/worker:229:20)
 ELIFECYCLE  Command failed with exit code 1.

System Info

System:
    OS: Linux cpe:/o:nixos:nixos:25.11 25.11 (Xantusia)
    Container: Yes
    Shell: 4.0.2 - /run/current-system/sw/bin/fish
  Binaries:
    Node: 22.18.0 - /run/current-system/sw/bin/node
    Yarn: 1.22.22 - /run/current-system/sw/bin/yarn
    npm: 10.9.3 - /run/current-system/sw/bin/npm
    pnpm: 10.15.0 - /run/current-system/sw/bin/pnpm
    bun: 1.2.20 - /run/current-system/sw/bin/bun
  npmPackages:
    @sveltejs/adapter-auto: 6.1.0 => 6.1.0 
    @sveltejs/adapter-node: 5.3.1 => 5.3.1 
    @sveltejs/kit: 2.37.0 => 2.37.0 
    @sveltejs/vite-plugin-svelte: 6.1.3 => 6.1.3 
    svelte: 5.38.6 => 5.38.6 
    vite: 7.1.3 => 7.1.3

Severity

blocking an upgrade

Additional Information

No response

[patte]

We just had the same issue. Exactly since 2.34.1 SvelteKit callsServer.init during build when before it didn't.

pnpm run build
...
13.48 ✓ 7800 modules transformed.
13.73 rendering chunks...
16.43 vite v7.1.4 building for production...
16.77 ✔ [paraglide-js] Compilation complete (message-modules)
16.78 transforming...
26.78 ✓ 7308 modules transformed.
27.16 rendering chunks...
28.20 computing gzip size...
28.46 .svelte-kit/output/client/_app/version.json                                     0.03 kB │ gzip:   0.05 kB
28.46 .svelte-kit/output/client/.vite/manifest.json                                  56.56 kB │ gzip:   6.62 kB
28.46 .svelte-kit/output/client/stats.html                                        2,936.29 kB │ gzip: 266.24 kB
28.46 .svelte-kit/output/client/network.html                                      2,959.05 kB │ gzip: 269.34 kB
28.46 .svelte-kit/output/client/_app/immutable/assets/31.BDHGAC5Q.css                 0.13 kB │ gzip:   0.12 kB
...
28.48 .svelte-kit/output/client/_app/immutable/chunks/CSRoEBTV.js                   143.11 kB │ gzip:  38.74 kB
28.48 .svelte-kit/output/client/_app/immutable/nodes/23.CEr48nNx.js                 372.53 kB │ gzip: 126.29 kB
28.48 .svelte-kit/output/client/_app/immutable/nodes/30.B90ps0bZ.js                 862.39 kB │ gzip: 241.62 kB
28.48 
28.48 (!) Some chunks are larger than 500 kB after minification. Consider:
28.48 - Using dynamic import() to code-split the application
28.48 - Use build.rollupOptions.output.manualChunks to improve chunking: https://rollupjs.org/configuration-options/#output-manualchunks
28.48 - Adjust chunk size limit for this warning via build.chunkSizeWarningLimit.
28.49 ✓ built in 12.06s
29.53 Failed to maintain, continuing anyway Error: missing DATABASE_URL
29.53     at createClient (file:///temp/dev/.svelte-kit/output/server/chunks/client.js:5:11)
29.53     at maintain (file:///temp/dev/.svelte-kit/output/server/chunks/hooks.server.js:239:23)
29.53     at Object.init (file:///temp/dev/.svelte-kit/output/server/chunks/hooks.server.js:348:43)
29.53     at file:///temp/dev/.svelte-kit/output/server/index.js:4292:24
29.53     at async Server.init (file:///temp/dev/.svelte-kit/output/server/index.js:4272:5)
29.53     at async prerender (file:///temp/dev/node_modules/.pnpm/@sveltejs+kit@2.34.1_@sveltejs+vite-plugin-svelte@6.1.3_svelte@5.38.6_vite@7.1.4_@types_e0495dbfcee79a24e861a1a7ab44adb5/node_modules/@sveltejs/kit/src/core/postbuild/prerender.js:129:2)
29.53     at async MessagePort.<anonymous> (file:///temp/dev/node_modules/.pnpm/@sveltejs+kit@2.34.1_@sveltejs+vite-plugin-svelte@6.1.3_svelte@5.38.6_vite@7.1.4_@types_e0495dbfcee79a24e861a1a7ab44adb5/node_modules/@sveltejs/kit/src/utils/fork.js:23:16)
29.55 
29.55 node:internal/event_target:1101
29.55   process.nextTick(() => { throw err; });
29.55                            ^
29.55 Error: connect ECONNREFUSED 127.0.0.1:5432
29.55     at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1637:16) {
29.55   errno: -111,
29.55   code: 'ECONNREFUSED',
29.55   syscall: 'connect',
29.55   address: '127.0.0.1',
29.55   port: 5432
29.55 }
29.55 
29.55 Node.js v24.7.0
29.82  ELIFECYCLE  Command failed with exit code 1.
------
Dockerfile:28
--------------------
  26 |     # build
  27 |     ENV NODE_OPTIONS=--max-old-space-size=4096
  28 | >>> RUN pnpm run build
  29 |     # build scripts
  30 |     RUN pnpm run build:scripts
--------------------
ERROR: failed to build: failed to solve: process "/bin/sh -c pnpm run build" did not complete successfully: exit code: 1

I think this comes from c5f7139#diff-ff09134d521cb6240a6576e7d0e61de568df90bf9b3aa649519c068783077a77 calling server.init before checking if there is anything to prerender.

To workaround the issue we skip init if npm_lifecycle_event === 'build'

export const init: ServerInit = async () => {
	// https://github.com/sveltejs/kit/issues/14347
	if (env.npm_lifecycle_event === 'build') {
		console.log('Skipping init during build / prerendering');
		return;
	}
	// ...
}

[1muen]

It also runs the handlers, so we would have to put that workaround into every package that exports a handler.

[teemingc]

The regression is introduced in @sveltejs/kit@2.34.1. https://github.com/sveltejs/kit/releases/tag/%40sveltejs%2Fkit%402.34.1

#14219 made a change that runs the init hook even if nothing needs to be prerendered. This was changed so that environment variables are loaded before the remote function files are imported. We currently import those remote function modules to check if they contain any prerendered remote functions. Ideally, the init hook only runs when something actually needs to be prerendered (as it was before).