The base property would be changed

[fengxinming]

Describe the bug

The base property would be changed when it got base on configResolved hook.

Reproduction

export default defineConfig({
  base: 'http://localhost:8000/',
  plugins: [
    {
      name: 'test',

      configResolved(config) {
        console.log(config.base);
      },
    }
  ]
});

it prints '/' not 'http://localhost:8000/'

System Info

MacBook Pro (Retina, 15-inch, Mid 2015)
macOS Mojave 10.14.6
[email protected]

Used Package Manager

npm

Logs

No response

Validations

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• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
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[hyf0]

 const config = {
  base: 'http://localhost:8000/',
  plugins: [
    {
      name: 'test',
      config(config) {
        console.log(config.base); // => 'http://localhost:8000/',
      },
      configResolved(config) {
        console.log(config.base); // => '/'
      },
    }
  ]
  // ...
}

resolveBaseUrl remove the origin part of base.

vite/packages/vite/src/node/config.ts

Lines 342 to 343 in eef51cb

	// resolve public base url
	const BASE_URL = resolveBaseUrl(config.base, command === 'build', logger)

Then, overwrite base.

vite/packages/vite/src/node/config.ts

Lines 408 to 415 in eef51cb

	const resolved: ResolvedConfig = {
	...config,
	configFile: configFile ? normalizePath(configFile) : undefined,
	configFileDependencies,
	inlineConfig,
	root: resolvedRoot,
	base: BASE_URL,
	resolve: resolveOptions,

It's hard to decide whether it is a bug? It does look confusing.

I personally don't consider it a bug and it should be mentioned in docs to avoid becoming an undefined behavior or split vite.config.js#base and resolved#base into two variable names.

[bluwy]

This looks like a dev-only behaviour, but fixing would cause a breaking change given how long this behaviour had existed, and I'm not sure if it's correct either. My understanding is that it's / in dev mode because the full http://localhost:8000 doesn't make sense as your files would definitely reside based on the Vite dev server, instead of an arbitrary localhost url.

Re config and resolvedConfig, it looks expected to me that Vite does a final resolve of the base URL in resolved. Maybe the better solution overall is indeed documentation, but I'm not sure where this resides at.

[sapphi-red]

Some slightly related conversations: #4274 (comment)

[ElMassimo]

Don't want to increase the noise here, so I edited my previous comment.

In most cases, users that want to provide a full origin to base in development should use server.origin instead, which was added in:

• fix: Allow custom asset URL origin in development #5104

[bluwy]

We also discussed in the last meeting that this is intentional. Vite will resolve the base for it's internal use. You can use server.origin for other cases.