Circular dependencies throw error 500

Describe the bug SvelteKit throws an error when using components with circular dependencies. Repository was created with commands shown on SK homepage and almost nothing was changed. I only included components from REPL.

Logs Console

Circular dependency: path/to/repo/src/routes/index.svelte -> /src/lib/App.svelte -> /src/lib/Structure.svelte -> /src/lib/C.svelte -> /src/lib/Structure.svelte

To Reproduce

I created repo with the problem here https://github.com/lukeeno/recursive-sveltekit

and also REPL with basically the same code, but in REPL it works https://svelte.dev/repl/c90b530e67c94b8995bf4bb5b7f70d3b?version=3.35.0

Expected behavior Not throwing error and recursively render components as shown in REPL

Stacktraces

Browser message

500
Cannot read property 'default' of null

TypeError: Cannot read property 'default' of null
    at path/to/repo/src/lib/C.svelte:7:22
    at Object.$$render (path/to/repo/node_modules/svelte/internal/index.js:1369:22)
    at eval (/src/lib/Structure.svelte:18:197)
    at Proxy.each (path/to/repo/node_modules/svelte/internal/index.js:1335:16)
    at path/to/repo/src/lib/Structure.svelte:15:7
    at Object.$$render (path/to/repo/node_modules/svelte/internal/index.js:1369:22)
    at eval (/src/lib/App.svelte:21:97)
    at Object.$$render (path/to/repo/node_modules/svelte/internal/index.js:1369:22)
    at eval (path/to/repo/src/routes/index.svelte:11:91)
    at Object.$$render (path/to/repo/node_modules/svelte/internal/index.js:1369:22)

Information about your SvelteKit Installation:

• The output of npx envinfo --system --npmPackages svelte,@sveltejs/kit --binaries --browsers

  System:
    OS: Linux 5.9 Manjaro Linux
    CPU: (8) x64 Intel(R) Core(TM) i7-10510U CPU @ 1.80GHz
    Memory: 1.29 GB / 15.34 GB
    Container: Yes
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 14.16.0 - /usr/bin/node
    npm: 7.6.3 - /usr/bin/npm
  Browsers:
    Brave Browser: unknown
    Firefox: 86.0.1
  npmPackages:
    @sveltejs/kit: next => 1.0.0-next.60 
    svelte: ^3.29.0 => 3.35.0

• Your browser Brave Version 1.20.103 Chromium: 88.0.4324.152 (Official Build) unknown (64-bit)

• Your adapter Node

Severity

Really severe if you need circular dependencies, but apart from that it’s okay

Additional context

Is there any workaround with async component loading?

[Buraburaite]

Fix just landed in Vite: https://github.com/vitejs/vite/pull/3950 @Rich-Harris

[Rich-Harris]

I guess this is a Vite issue. It’s definitely solvable — SvelteKit used to have an SSR runtime that handled this case, but we removed it because Vite implemented something very similar — though I can’t speak to how straightforward it would be to add it to Vite. Looks like there’s a couple of related issues already, e.g. https://github.com/vitejs/vite/issues/2258