feat(bundled-dev): support import.meta.hot.acceptExports

packages/vite/src/client/bundledDevClient.ts

@@ -13,6 +13,8 @@ import {
   updateStyle,
 } from './client'
 
+declare const __HMR_PARTIAL_ACCEPT__: boolean
+
 // keep the same public exports as `client.ts`, which this entry replaces when inlined
 export {
   createHotContext,
@@ -60,6 +62,7 @@ if (typeof DevRuntime !== 'undefined') {
     runtime,
     {
       base,
+      partialAccept: __HMR_PARTIAL_ACCEPT__,
       beforeApply: clearOverlayOrReloadOnFirstUpdate,
     },
   )

packages/vite/src/client/bundledDevHmrClient.ts

@@ -9,6 +9,7 @@ import type { NormalizedModuleRunnerTransport } from '../shared/moduleRunnerTran
 /** the subset of `__rolldown_runtime__` the HMR client uses */
 export interface RolldownRuntimeLike {
   getImporters(id: string): string[]
+  getImportedBindings?(importer: string, id: string): string[] | undefined
   isExecuted(id: string): boolean
   hasFactory(id: string): boolean
   removeModuleCache(id: string): void
@@ -33,6 +34,7 @@ type HmrUpdate =
 
 export interface BundledDevHMRClientOptions {
   base: string
+  partialAccept: boolean
   /** returning `'reload'` aborts the apply — the hook reloads the page itself */
   beforeApply: () => 'reload' | 'continue'
 }
@@ -41,6 +43,8 @@ export class BundledDevHMRClient extends HMRClient {
   private applyQueue = Promise.resolve()
   private lastSeq = 0
   private reloadPending = false
+  private acceptedExportsMap = new Map<string, Set<string>>()
+  private partialAcceptCallbacks = new WeakSet<(...args: any[]) => void>()
 
   constructor(
     logger: HMRLogger,
@@ -57,11 +61,39 @@ export class BundledDevHMRClient extends HMRClient {
 
   isSelfAccepted(id: string): boolean {
     return (
-      this.hotModulesMap.get(id)?.callbacks.some((c) => c.deps.includes(id)) ??
-      false
+      this.hotModulesMap
+        .get(id)
+        ?.callbacks.some(
+          (c) => c.deps.includes(id) && !this.partialAcceptCallbacks.has(c.fn),
+        ) ?? false
     )
   }
 
+  registerAcceptedExports(
+    owner: string,
+    exportNames: string | readonly string[],
+    callback: (...args: any[]) => void,
+  ): void {
+    const accepted = this.acceptedExportsMap.get(owner) ?? new Set<string>()
+    for (const name of typeof exportNames === 'string'
+      ? [exportNames]
+      : exportNames) {
+      accepted.add(name)
+    }
+    this.acceptedExportsMap.set(owner, accepted)
+    this.partialAcceptCallbacks.add(callback)
+  }
+
+  clearAcceptedExports(owner: string): void {
+    this.acceptedExportsMap.delete(owner)
+  }
+
+  private acceptsAllExports(id: string, accepted: Set<string>): boolean {
+    const exports = this.runtime.loadExports(id)
+    if (typeof exports !== 'object' || exports == null) return false
+    return Object.keys(exports).every((name) => accepted.has(name))
+  }
+
   acceptsDep(parent: string, id: string): boolean {
     return (
       this.hotModulesMap
@@ -113,24 +145,37 @@ export class BundledDevHMRClient extends HMRClient {
         reason: `update propagated back to ${firstInvalidatedBy}, which already called \`import.meta.hot.invalidate()\``,
       }
     }
-    if (this.isSelfAccepted(id)) {
+    const acceptedExports = this.acceptedExportsMap.get(id)
+    if (
+      this.isSelfAccepted(id) ||
+      (acceptedExports && this.acceptsAllExports(id, acceptedExports))
+    ) {
       boundaries.push({
         boundary: id,
         acceptedVia: id,
         isWithinCircularImport: this.isNodeWithinCircularImports(id, stack),
       })
       return
     }
+    if (acceptedExports) {
+      boundaries.push({
+        boundary: id,
+        acceptedVia: id,
+        isWithinCircularImport: this.isNodeWithinCircularImports(id, stack),
+      })
+    }
     const parents = this.runtime
       .getImporters(id)
       .filter((p) => this.runtime.isExecuted(p))
     if (!parents.length) {
+      if (acceptedExports) return
       return {
         type: 'full-reload',
         reason: `no hmr boundary found for module \`${id}\``,
       }
     }
     for (const parent of parents) {
+      if (acceptedExports && parent === id) continue
       const subChain = [...stack, parent]
       if (this.acceptsDep(parent, id)) {
         boundaries.push({
@@ -143,6 +188,12 @@ export class BundledDevHMRClient extends HMRClient {
         })
         continue
       }
+      if (acceptedExports && this.options.partialAccept) {
+        const bindings = this.runtime.getImportedBindings?.(parent, id)
+        if (bindings && bindings.every((name) => acceptedExports.has(name))) {
+          continue
+        }
+      }
       if (!stack.includes(parent)) {
         const fullReload = this.bubble(
           parent,
@@ -425,6 +476,16 @@ export class BundledDevHMRContext extends HMRContext {
     private owner: string,
   ) {
     super(bundledDevClient, owner)
+    bundledDevClient.clearAcceptedExports(owner)
+  }
+
+  override acceptExports(
+    exportNames: string | readonly string[],
+    callback?: (data: any) => void,
+  ): void {
+    const fn = ([mod]: any[]) => callback?.(mod)
+    this.bundledDevClient.registerAcceptedExports(this.owner, exportNames, fn)
+    this.acceptDeps([this.owner], fn)
   }
 
   override invalidate(message: string): void {

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

@@ -122,6 +122,9 @@ async function createClientConfigValueReplacer(
   const hmrTimeoutReplacement = escapeReplacement(timeout)
   const hmrEnableOverlayReplacement = escapeReplacement(overlay)
   const hmrConfigNameReplacement = escapeReplacement(hmrConfigName)
+  const hmrPartialAcceptReplacement = escapeReplacement(
+    config.experimental.hmrPartialAccept,
+  )
   const wsTokenReplacement = escapeReplacement(config.webSocketToken)
   const serverForwardConsoleReplacement = escapeReplacement(
     config.server.forwardConsole as any,
@@ -140,6 +143,7 @@ async function createClientConfigValueReplacer(
       .replace(`__HMR_TIMEOUT__`, hmrTimeoutReplacement)
       .replace(`__HMR_ENABLE_OVERLAY__`, hmrEnableOverlayReplacement)
       .replace(`__HMR_CONFIG_NAME__`, hmrConfigNameReplacement)
+      .replace(`__HMR_PARTIAL_ACCEPT__`, hmrPartialAcceptReplacement)
       .replace(`__WS_TOKEN__`, wsTokenReplacement)
       .replace(`__SERVER_FORWARD_CONSOLE__`, serverForwardConsoleReplacement)
 }

packages/vite/src/shared/hmr.ts

@@ -75,8 +75,8 @@ export class HMRContext implements ViteHotContext {
     }
   }
 
-  // export names (first arg) are irrelevant on the client side, they're
-  // extracted in the server for propagation
+  // in unbundled dev the export names (first arg) are extracted by the server;
+  // the bundled-dev context overrides this method and reads them itself
   acceptExports(
     _: string | readonly string[],
     callback?: (data: any) => void,
@@ -151,7 +151,7 @@ export class HMRContext implements ViteHotContext {
     this.hmrClient.send({ type: 'custom', event, data })
   }
 
-  private acceptDeps(
+  protected acceptDeps(
     deps: string[],
     callback: HotCallback['fn'] = () => {},
   ): void {