Setting kit.files.src results in deprecation message

[luislavena]

Describe the bug

Hello folks,

Made a fresh sv create my-app using Bun and ended with the following versions:

# bun pm ls
/workspace/exp-svelte-demo node_modules (101)
├── @fontsource/fira-mono@5.2.6
├── @neoconfetti/svelte@2.2.2
├── @sveltejs/adapter-auto@6.1.0
├── @sveltejs/kit@2.29.1
├── @sveltejs/vite-plugin-svelte@6.1.2
├── svelte@5.38.1
├── svelte-check@4.3.1
├── typescript@5.9.2
└── vite@7.1.2

Following #14152, wanted to test placing all SvelteKit files in src/frontend (to co-exists with another codebase):

import adapter from "@sveltejs/adapter-auto";
import { vitePreprocess } from "@sveltejs/vite-plugin-svelte";

/** @type {import('@sveltejs/kit').Config} */
const config = {
  preprocess: vitePreprocess(),

  kit: {
    adapter: adapter(),
    files: {
      src: "src/frontend",
    },
  },
};

export default config;

When bun run dev, got the following in the terminal:

The `config.kit.files.src` option is deprecated, and will be removed in a future version

Looking at the changes done in #14152, specially the fixture config file:

https://github.com/sveltejs/kit/pull/14152/files#diff-da2134357ccc2d30bee7b3618668fc1fb012eca2c53ee6dc46339a3345c8819e

export default {
	kit: {
		files: {
			src: 'source'
		}
	}
};

Appears to be doing the exact same configuration, yet this generates the warning.

Looking to the other changes, I saw a deprecate on the new src usage:

https://github.com/sveltejs/kit/pull/14152/files#diff-1411a71a2bbcac1c2a0277a836799b279873cf32e82c52ad9aca3c66307ca229

			files: object({
				src: deprecate(string('src')),
				assets: deprecate(string('static')),
				hooks: object({
					client: deprecate(string(null)),
					server: deprecate(string(null)),
					universal: deprecate(string(null))
				}),
				lib: deprecate(string(null)),
				params: deprecate(string(null)),
				routes: deprecate(string(null)),
				serviceWorker: deprecate(string(null)),
				appTemplate: deprecate(string(null)),
				errorTemplate: deprecate(string(null))
			}),

But makes no sense to deprecate the freshly added option.

I might be missing something or this deprecation warning is an error?

Thank you in advance and apologies if I've missed something in the linked issues 🙏
❤️ ❤️ ❤️

Reproduction

• bunx sv create-app my-app
• mv src frontend
• mkdir -p src
• mv frontend src/
• Edit svelte.config.js with kit.files.src as src/frontend
• bun run dev

Logs

The `config.kit.files.src` option is deprecated, and will be removed in a future version

System Info

* Alpine Linux 3.22.1 (aarch64)
* Bun 1.2.20
* Svelte 5.38.1
* SvelteKit 2.29.1
* Vite 7.1.2

Severity

annoyance

Additional Information

No response

[Rich-Harris]

This is intentional: #14211 (comment)

All the kit.files.src options will be removed in SvelteKit 3, as they add needless complexity and variance between different SvelteKit codebases. It's confusing for both humans and LLMs.

If you have two codebases, then you really should be using a workspace.

[luislavena]

Thank you for the response and the explanation. I really asked this since was but easy to conclude that from the linked issues.

I'm not 100% sure if this fits the workspace approach but I will give it a try (not a monorepo per-se).

Thank you once again for the response and the details.

❤️❤️❤️

[Rich-Harris]

For anyone finding their way here (this page was linked from Stack Overflow, for example) — more context here: #14240