Wrap in experiment.

docs/guide/monorepo-packages.md

@@ -10,7 +10,19 @@ This method is based entirely around `package.json` entry points. For local pack
 
 - Requires entry points within the package's `package.json`.
 - Requires package (npm, pnpm, yarn) workspaces.
-- Requires the package to exist in `node_modules` (symlinked via workspaces).
+- Requires the package to be symlinked in `node_modules`.
+
+Because this functionality is experimental, it must be enabled in your config.
+
+```js
+import { defineConfig } from 'vite'
+
+export default defineConfig({
+  experimental: {
+    vitePackageEntryPoints: true,
+  },
+})
+```
 
 ### Implementation
 
@@ -44,11 +56,11 @@ For packages that are depended on (not symlinked in `node_modules`), the `vite`
 
 ### Caveats
 
-- If using `vite` exports condition:
+- If using `vite` export condition:
   - To support deep imports, the `./*` entry point must be defined, which maps 1:1 to the file system.
-  - To support multiple source files with different extensions, use an array as the `vite` condition (example above).
+  - To support multiple source files with different extensions, use an array as the `vite` condition value (example above).
 - If using `vite` main entry point:
-  - Only default imports are supported.
+  - Only default/index imports are supported.
   - Deep imports are not supported.
 - Packages that are not symlinked into `node_modules` will _not_ use the `vite` entry points. For reference, `workspace:`, `portal:`, and `link:` are supported, while `file:`, `git:`, etc are not.
 

packages/vite/src/node/config.ts

@@ -310,6 +310,15 @@ export interface ExperimentalOptions {
    * @default false
    */
   skipSsrTransform?: boolean
+  /**
+   * Resolves source files of local packages (in a monorepo workspace) using `package.json`
+   * entry points. If using `exports`, uses the `vite` condition. Otherwise, uses the `vite`
+   * main-like field.
+   *
+   * @experimental
+   * @default false
+   */
+  vitePackageEntryPoints?: boolean
 }
 
 export interface LegacyOptions {
@@ -1257,7 +1266,7 @@ function optimizeDepsDisabledBackwardCompatibility(
       }
       resolved.logger.warn(
         colors.yellow(`(!) Experimental ${optimizeDepsPath}optimizeDeps.disabled and deps pre-bundling during build were removed in Vite 5.1.
-    To disable the deps optimizer, set ${optimizeDepsPath}optimizeDeps.noDiscovery to true and ${optimizeDepsPath}optimizeDeps.include as undefined or empty. 
+    To disable the deps optimizer, set ${optimizeDepsPath}optimizeDeps.noDiscovery to true and ${optimizeDepsPath}optimizeDeps.include as undefined or empty.
     Please remove ${optimizeDepsPath}optimizeDeps.disabled from your config.
     ${
       commonjsPluginDisabled

packages/vite/src/node/plugins/index.ts

@@ -72,6 +72,7 @@ export async function resolvePlugins(
         isBuild && config.build.ssr
           ? (id, importer) => shouldExternalizeForSSR(id, importer, config)
           : undefined,
+      vitePackageEntryPoints: config.experimental.vitePackageEntryPoints,
     }),
     htmlInlineProxyPlugin(config),
     cssPlugin(config),

packages/vite/src/node/plugins/resolve.ts

@@ -125,6 +125,9 @@ export interface InternalResolveOptions extends Required<ResolveOptions> {
    * @internal
    */
   idOnly?: boolean
+
+  // Maps to the experiment of the same name
+  vitePackageEntryPoints?: boolean
 }
 
 export function resolvePlugin(resolveOptions: InternalResolveOptions): Plugin {
@@ -980,7 +983,7 @@ export function resolvePackageEntry(
       const mainFields = [...options.mainFields]
 
       // Support `vite` entry point field for local packages
-      if (pkg.inWorkspace) {
+      if (pkg.inWorkspace && options.vitePackageEntryPoints) {
         mainFields.unshift('vite')
       }
 
@@ -1088,7 +1091,7 @@ function resolveExportsOrImports(
   })
 
   // Support `vite` condition for local packages
-  if (pkg.inWorkspace) {
+  if (pkg.inWorkspace && options.vitePackageEntryPoints) {
     conditions.unshift('vite')
   }
 

playground/monorepo-vite-condition/exports/package.json

@@ -16,7 +16,10 @@
       "module": "./build/index.js"
     },
     "./*": {
-      "vite": ["./src/*.ts", "./src/*.tsx"],
+      "vite": [
+        "./src/*.ts",
+        "./src/*.tsx"
+      ],
       "module": "./build/*.js"
     }
   }

playground/monorepo-vite-condition/root/vite.config.js

@@ -5,4 +5,7 @@ export default defineConfig({
     // None!
     alias: {},
   },
+  experimental: {
+    vitePackageEntryPoints: true,
+  },
 })