fix: skip client build if all routes have CSR disabled#15936

teemingc · 2026-05-31T18:09:59Z

Seeing if we can remove client nodes if they're unused. Disabling CSR in combination with server-side resolution should help obscure routes.

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changeset-bot · 2026-05-31T18:10:03Z

🦋 Changeset detected

Latest commit: 1068cd7

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svelte-docs-bot · 2026-05-31T18:13:55Z

Preview: https://svelte-dev-git-preview-kit-15936-svelte.vercel.app/

Rich-Harris · 2026-06-02T02:49:27Z

I don't think this is right. csr = false means that we don't load the client if we land on the page directly. If we navigate to the page from a different page with csr = true, then we can't 'unload' the client, we just treat it as a normal client-side navigation. With this change, that's impossible, because the client will attempt to import a non-existent module.

And it's not like we can opt out of client-side navigation in those cases, because we would need to either a) store the information about which pages have csr = false in the route manifest or b) fall back to a hard reload after a soft navigation failed. Neither seems desirable.

So I think the only time we would want to get rid of these files is if we know that all routes are csr = false, and in that case we'd just skip the client build altogether.

teemingc · 2026-06-02T04:54:53Z

I don't think this is right. csr = false means that we don't load the client if we land on the page directly. If we navigate to the page from a different page with csr = true, then we can't 'unload' the client, we just treat it as a normal client-side navigation. With this change, that's impossible, because the client will attempt to import a non-existent module.

Ah yeah, I overlooked that.

So I think the only time we would want to get rid of these files is if we know that all routes are csr = false, and in that case we'd just skip the client build altogether.

Skipping the client build might be a little tricky. We still use the CSS files generated from that build, which is also why we couldn’t simply omit the nodes from the client build but had to delete them after the build.

Rich-Harris · 2026-06-02T16:57:20Z

Ah. We don't generate CSS files during the server build?

teemingc · 2026-06-02T17:35:05Z

We do but our current logic parses the client manifest to associate the client stylesheets with the route. Let me see if I can rework that to use the server stylesheets instead...

teemingc · 2026-06-08T11:54:53Z

 	}

+	/** path to the `.svelte-kit` directory */
+	const out_dir = normalizePath(kit.outDir);


Moved this out of the for loop so that it only needs to be done once.

teemingc · 2026-06-08T14:42:59Z

 	internal.set_read_implementation((file) => createReadableStream(`${server_root}/server/${file}`));

-	// first, build server nodes without the client manifest so we can analyse it
-	build_server_nodes(out, config, manifest_data, server_manifest, null, null, null);


Moved this to vite/index.js so we can pass it server chunks

teemingc · 2026-06-08T14:44:23Z

Made this more generic so that it fully builds the server nodes even if it only gets the server manifest and no client manifest

teemingc · 2026-06-08T14:46:21Z

+						},
+						experimental: {
+							// Allows us to use relative paths in as many places as we can
+							renderBuiltUrl(filename, { ssr, hostType }) {


We already do this in version-3 because Vite's buildApp hook doesn't accept multiple base configs. This also ensures the server and client builds emit CSS with the correct asset paths

teemingc · 2026-06-08T14:47:10Z

+				/** @type {Manifest | null} */
+				let client_manifest = null;
+
+				if (!skip_client_build) {


All the changes below this essentially wraps the client build stuff in an if block.

teemingc · 2026-06-08T14:47:39Z

 						);
 					}
-
-					secondary_build_started = false;


Moved this into the if block that executes the client build.

teemingc · 2026-06-08T14:48:48Z

Mostly changes to accept the manifest._.client arg rather than the entire manifest.

teemingc · 2026-06-08T14:49:59Z

+	expect(files).toBe(false);
+
+	await page.goto('/assets');
+	const src = await page.locator('img').getAttribute('src');


Check that assets are still public even if we skip the client build

teemingc · 2026-06-08T14:50:22Z

-		minify: false
+		minify: false,
+		// TODO: remove when we stop testing for vite on node 18
+		assetsInlineLimit: 0


?no-inline import query string doesn't work on older Vite versions which we still test for

Rich-Harris

outstanding!

Assets in the public directory `static` are not copied to the `output/client` directory during the server build. This means if the client build is skipped (which is now possible because of #15936), the public assets are never copied over. This PR manually copies these assets over because setting the Vite option `copyPublicDir: true` simply copies them to the `output/server` directory. --- ### Please don't delete this checklist! Before submitting the PR, please make sure you do the following: - [ ] 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 - [ ] Run the tests with `pnpm test` and lint the project with `pnpm lint` and `pnpm check` ### Changesets - [ ] 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:`. No changeset because #15936 hasn't been released yet. ### Edits - [x] Please ensure that 'Allow edits from maintainers' is checked. PRs without this option may be closed.

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/kit@2.65.0 ### Minor Changes - feat: allow queries to refresh other queries ([#16012](#16012)) ### Patch Changes - fix: dedupe remote data ([#15991](#15991)) - fix: skip client build if all routes have CSR disabled ([#15936](#15936)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

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 version-3, this PR will be updated. ⚠️

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⚠️ `version-3` is currently in **pre mode** so this branch has prereleases rather than normal releases. If you want to exit prereleases, run `changeset pre exit` on `version-3`. ⚠️

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⚠️ # Releases ## @sveltejs/kit@3.0.0-next.3 ### Minor Changes - feat: allow queries to refresh other queries ([#16012](#16012)) ### Patch Changes - fix: dedupe remote data ([#15991](#15991)) - fix: skip client build if all routes have CSR disabled ([#15936](#15936)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

charbelnicolas · 2026-06-12T04:04:47Z

I'm getting 404 errors all over the place after updating sveltekit and this seems to be the culprit. What am I supposed to do?

teemingc · 2026-06-12T04:10:23Z

I'm getting 404 errors all over the place after updating sveltekit and this seems to be the culprit. What am I supposed to do?

This is probably related to #16013 which is an issue with setting paths.relative: false in the kit config.

fix and test

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teemingc added 4 commits June 1, 2026 02:25

fix typescript

47f417f

fix test

fee52a6

disable test for server side router resolution

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changeset

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teemingc marked this pull request as ready for review June 1, 2026 14:27

teemingc marked this pull request as draft June 2, 2026 17:35

teemingc added 9 commits June 7, 2026 23:33

Merge branch 'main' into remove-unused-client-nodes

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try

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try

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always copy over stylesheets

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Merge branch 'main' into remove-unused-client-nodes

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fix

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this should work

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types

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generate types

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teemingc changed the title ~~fix: remove unused client nodes if CSR is disabled~~ fix: skip client build if all nodes have CSR disabled Jun 8, 2026

teemingc added 2 commits June 8, 2026 16:32

move test

2e61e1b

edit changeset

429822e

teemingc changed the title ~~fix: skip client build if all nodes have CSR disabled~~ fix: skip client build if all routes have CSR disabled Jun 8, 2026

Merge branch 'main' into remove-unused-client-nodes

07a8835

teemingc commented Jun 8, 2026

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teemingc marked this pull request as ready for review June 8, 2026 11:57

vercel Bot reviewed Jun 8, 2026

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Comment thread packages/kit/src/exports/vite/index.js Outdated

teemingc added 7 commits June 8, 2026 22:38

revert

5e9dc4a

ensure assets are copied

7eb1fc5

format

64defd5

fix for old vite

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Merge branch 'main' into remove-unused-client-nodes

e051b1a

cant wait to remove vite node18 tests

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fix

1068cd7

teemingc commented Jun 8, 2026

View reviewed changes

Rich-Harris approved these changes Jun 8, 2026

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teemingc merged commit 3968fb9 into main Jun 8, 2026
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teemingc deleted the remove-unused-client-nodes branch June 8, 2026 22:39

This was referenced Jun 8, 2026

Version Packages #15988

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Version Packages (next) #15996

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teemingc mentioned this pull request Jun 10, 2026

fix: copy public directory assets if client build is skipped #16004

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murayy mentioned this pull request Jun 11, 2026

NS_ERROR_CORRUPTED_CONTENT with kit 2.65.0 #16013

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