vitejs/vite · error · Error

When "build.cssCodeSplit: false" is set, "rolldownOptions.in

Error message

When "build.cssCodeSplit: false" is set, "rolldownOptions.input" should not include CSS files.

What it means

In resolveRolldownOptions (build.ts:633-644), when build.cssCodeSplit is false and any resolved input ends in .css, Vite throws. With code splitting disabled, CSS cannot be treated as a separate entry; CSS must be imported from JS rather than listed directly as an input.

Source

Thrown at packages/vite/src/node/build.ts:641

      ? resolve(options.ssr)
      : options.rolldownOptions.input ||
        (topLevelInput ?? resolve('index.html'))

  if (ssr && typeof input === 'string' && input.endsWith('.html')) {
    throw new Error(
      `rolldownOptions.input should not be an html file when building for SSR. ` +
        `Please specify a dedicated SSR entry.`,
    )
  }
  if (options.cssCodeSplit === false) {
    const inputs =
      typeof input === 'string'
        ? [input]
        : Array.isArray(input)
          ? input
          : Object.values(input)
    if (inputs.some((input) => input.endsWith('.css'))) {
      throw new Error(
        `When "build.cssCodeSplit: false" is set, "rolldownOptions.input" should not include CSS files.`,
      )
    }
  }

  const outDir = resolve(options.outDir)

  // inject environment and ssr arg to plugin load/transform hooks
  const plugins = environment.plugins.map((p) =>
    injectEnvironmentToHooks(environment, chunkMetadataMap, p),
  )

  const rolldownOptions: RolldownOptions = {
    preserveEntrySignatures: ssr
      ? 'allow-extension'
      : libOptions
        ? 'strict'
        : false,

View on GitHub (pinned to 89620f09af)

Solutions

Remove .css files from rolldownOptions.input and import the CSS from a JS/TS entry instead.
If you genuinely need CSS as an entry, leave cssCodeSplit at its default (true).
Move shared styles into a JS entry that does import './styles.css'.

Example fix

// before
build: { cssCodeSplit: false, rollupOptions: { input: { main: 'src/main.ts', styles: 'src/styles.css' } } }
// after
build: { cssCodeSplit: false, rollupOptions: { input: { main: 'src/main.ts' } } } // src/main.ts imports './styles.css'

Defensive patterns

Strategy: validation

Validate before calling

if (config.build?.cssCodeSplit === false) {
  const inputs = config.build?.rolldownOptions?.input
  const list = typeof inputs === 'string' ? [inputs] : Array.isArray(inputs) ? inputs : inputs ? Object.values(inputs) : []
  if (list.some((f) => f.endsWith('.css'))) {
    throw new Error('CSS inputs are not allowed when cssCodeSplit is false')
  }
}

Type guard

function hasNoCssInput(inputs: unknown): boolean {
  const list = typeof inputs === 'string' ? [inputs] : Array.isArray(inputs) ? inputs : inputs ? Object.values(inputs as Record<string, string>) : []
  return !list.some((f: string) => f.endsWith('.css'))
}

Prevention

Import CSS from JS entries rather than listing stylesheets as inputs.
If you need CSS entries, keep cssCodeSplit at its default (true).
Review rolldownOptions.input whenever toggling cssCodeSplit.

When it happens

Trigger: Setting build: { cssCodeSplit: false } while rolldownOptions.input (or the default input) includes one or more .css files.

Common situations: Trying to ship a single combined CSS file by disabling code splitting, but also listing the stylesheet as a build entry; copying a multi-entry config that included a CSS entry.

Related errors

AI-assisted analysis of vitejs/vite@89620f09af (2026-08-03). Data as JSON: /data/errors/024c234125b5156b.json. Report an issue: GitHub.