feat(hmr): experimental.hmrPartialAccept

packages/vite/LICENSE.md

@@ -1963,6 +1963,35 @@ Repository: git+https://github.com/json5/json5.git
 
 ---------------------------------------
 
+## jsonc-parser
+License: MIT
+By: Microsoft Corporation
+Repository: https://github.com/microsoft/node-jsonc-parser
+
+> The MIT License (MIT)
+> 
+> Copyright (c) Microsoft
+> 
+> Permission is hereby granted, free of charge, to any person obtaining a copy
+> of this software and associated documentation files (the "Software"), to deal
+> in the Software without restriction, including without limitation the rights
+> to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+> copies of the Software, and to permit persons to whom the Software is
+> furnished to do so, subject to the following conditions:
+> 
+> The above copyright notice and this permission notice shall be included in all
+> copies or substantial portions of the Software.
+> 
+> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+> IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+> FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+> AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+> LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+> OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+> SOFTWARE.
+
+---------------------------------------
+
 ## launch-editor
 License: MIT
 By: Evan You
@@ -2162,6 +2191,34 @@ Repository: git://github.com/isaacs/minimatch.git
 
 ---------------------------------------
 
+## mlly
+License: MIT
+Repository: unjs/mlly
+
+> MIT License
+> 
+> Copyright (c) 2022 UnJS
+> 
+> Permission is hereby granted, free of charge, to any person obtaining a copy
+> of this software and associated documentation files (the "Software"), to deal
+> in the Software without restriction, including without limitation the rights
+> to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+> copies of the Software, and to permit persons to whom the Software is
+> furnished to do so, subject to the following conditions:
+> 
+> The above copyright notice and this permission notice shall be included in all
+> copies or substantial portions of the Software.
+> 
+> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+> IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+> FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+> AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+> LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+> OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+> SOFTWARE.
+
+---------------------------------------
+
 ## mrmime
 License: MIT
 By: Luke Edwards

packages/vite/package.json

@@ -99,6 +99,7 @@
     "launch-editor-middleware": "^2.4.0",
     "magic-string": "^0.26.2",
     "micromatch": "^4.0.5",
+    "mlly": "^0.5.1",
     "mrmime": "^1.0.1",
     "node-forge": "^1.3.1",
     "okie": "^1.0.1",

packages/vite/src/client/client.ts

@@ -452,6 +452,12 @@ export function createHotContext(ownerPath: string): ViteHotContext {
       }
     },
 
+    // export names (first arg) are irrelevant on the client side, they're
+    // extracted in the server for propagation
+    acceptExports(_: string | readonly string[], callback?: any) {
+      acceptDeps([ownerPath], callback && (([mod]) => callback(mod)))
+    },
+
     dispose(cb) {
       disposeMap.set(ownerPath, cb)
     },

packages/vite/src/node/config.ts

@@ -247,6 +247,14 @@ export interface ExperimentalOptions {
    * @default false
    */
   importGlobRestoreExtension?: boolean
+
+  /**
+   * Enables support of HMR partial accept via `import.meta.hot.acceptExports`.
+   *
+   * @experimental
+   * @default false
+   */
+  hmrPartialAccept?: boolean
 }
 
 export interface LegacyOptions {

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

@@ -258,9 +258,11 @@ export function cssPlugin(config: ResolvedConfig): Plugin {
             moduleGraph.updateModuleInfo(
               thisModule,
               depModules,
+              null,
               // The root CSS proxy module is self-accepting and should not
               // have an explicit accept list
               new Set(),
+              null,
               isSelfAccepting,
               ssr
             )

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

@@ -7,6 +7,7 @@ import type { ImportSpecifier } from 'es-module-lexer'
 import { init, parse as parseImports } from 'es-module-lexer'
 import { parse as parseJS } from 'acorn'
 import type { Node } from 'estree'
+import { findStaticImports, parseStaticImport } from 'mlly'
 import { makeLegalIdentifier } from '@rollup/pluginutils'
 import type { ViteDevServer } from '..'
 import {
@@ -20,7 +21,8 @@ import {
 import {
   debugHmr,
   handlePrunedModules,
-  lexAcceptedHmrDeps
+  lexAcceptedHmrDeps,
+  lexAcceptedHmrExports
 } from '../server/hmr'
 import {
   cleanUrl,
@@ -84,6 +86,48 @@ function markExplicitImport(url: string) {
   return url
 }
 
+async function extractImportedBindings(
+  id: string,
+  source: string,
+  importSpec: ImportSpecifier,
+  importedBindings: Map<string, Set<string>>
+) {
+  let bindings = importedBindings.get(id)
+  if (!bindings) {
+    bindings = new Set<string>()
+    importedBindings.set(id, bindings)
+  }
+
+  const isDynamic = importSpec.d > -1
+  const isMeta = importSpec.d === -2
+  if (isDynamic || isMeta) {
+    // this basically means the module will be impacted by any change in its dep
+    bindings.add('*')
+    return
+  }
+
+  const exp = source.slice(importSpec.ss, importSpec.se)
+  const [match0] = findStaticImports(exp)
+  if (!match0) {
+    return
+  }
+  const parsed = parseStaticImport(match0)
+  if (!parsed) {
+    return
+  }
+  if (parsed.namespacedImport) {
+    bindings.add('*')
+  }
+  if (parsed.defaultImport) {
+    bindings.add('default')
+  }
+  if (parsed.namedImports) {
+    for (const name of Object.keys(parsed.namedImports)) {
+      bindings.add(name)
+    }
+  }
+}
+
 /**
  * Server-only plugin that lexes, resolves, rewrites and analyzes url imports.
  *
@@ -116,6 +160,7 @@ function markExplicitImport(url: string) {
 export function importAnalysisPlugin(config: ResolvedConfig): Plugin {
   const { root, base } = config
   const clientPublicPath = path.posix.join(base, CLIENT_PUBLIC_PATH)
+  const enablePartialAccept = config.experimental?.hmrPartialAccept
   let server: ViteDevServer
 
   return {
@@ -143,9 +188,10 @@ export function importAnalysisPlugin(config: ResolvedConfig): Plugin {
       const start = performance.now()
       await init
       let imports: readonly ImportSpecifier[] = []
+      let exports: readonly string[] = []
       source = stripBomTag(source)
       try {
-        imports = parseImports(source)[0]
+        ;[imports, exports] = parseImports(source)
       } catch (e: any) {
         const isVue = importer.endsWith('.vue')
         const maybeJSX = !isVue && isJSRequest(importer)
@@ -204,6 +250,11 @@ export function importAnalysisPlugin(config: ResolvedConfig): Plugin {
         start: number
         end: number
       }>()
+      let isPartiallySelfAccepting = false
+      const acceptedExports = new Set<string>()
+      const importedBindings = enablePartialAccept
+        ? new Map<string, Set<string>>()
+        : null
       const toAbsoluteUrl = (url: string) =>
         path.posix.resolve(path.posix.dirname(importerModule.url), url)
 
@@ -344,7 +395,14 @@ export function importAnalysisPlugin(config: ResolvedConfig): Plugin {
             hasHMR = true
             if (source.slice(end + 4, end + 11) === '.accept') {
               // further analyze accepted modules
-              if (
+              if (source.slice(end + 4, end + 18) === '.acceptExports') {
+                lexAcceptedHmrExports(
+                  source,
+                  source.indexOf('(', end + 18) + 1,
+                  acceptedExports
+                )
+                isPartiallySelfAccepting = true
+              } else if (
                 lexAcceptedHmrDeps(
                   source,
                   source.indexOf('(', end + 11) + 1,
@@ -464,6 +522,16 @@ export function importAnalysisPlugin(config: ResolvedConfig): Plugin {
           // make sure to normalize away base
           const urlWithoutBase = url.replace(base, '/')
           importedUrls.add(urlWithoutBase)
+
+          if (enablePartialAccept && importedBindings) {
+            extractImportedBindings(
+              resolvedId,
+              source,
+              imports[index],
+              importedBindings
+            )
+          }
+
           if (!isDynamicImport) {
             // for pre-transforming
             staticImportedUrls.add({ url: urlWithoutBase, id: resolvedId })
@@ -531,6 +599,8 @@ export function importAnalysisPlugin(config: ResolvedConfig): Plugin {
           `${
             isSelfAccepting
               ? `[self-accepts]`
+              : isPartiallySelfAccepting
+              ? `[accepts-exports]`
               : acceptedUrls.size
               ? `[accepts-deps]`
               : `[detected api usage]`
@@ -585,10 +655,22 @@ export function importAnalysisPlugin(config: ResolvedConfig): Plugin {
         if (ssr && importerModule.isSelfAccepting) {
           isSelfAccepting = true
         }
+        // a partially accepted module that accepts all its exports
+        // behaves like a self-accepted module in practice
+        if (
+          !isSelfAccepting &&
+          isPartiallySelfAccepting &&
+          acceptedExports.size >= exports.length &&
+          exports.every((name) => acceptedExports.has(name))
+        ) {
+          isSelfAccepting = true
+        }
         const prunedImports = await moduleGraph.updateModuleInfo(
           importerModule,
           importedUrls,
+          importedBindings,
           normalizedAcceptedUrls,
+          isPartiallySelfAccepting ? acceptedExports : null,
           isSelfAccepting,
           ssr
         )

packages/vite/src/node/server/hmr.ts

@@ -201,6 +201,18 @@ export async function handleFileAddUnlink(
   }
 }
 
+function areAllImportsAccepted(
+  importedBindings: Set<string>,
+  acceptedExports: Set<string>
+) {
+  for (const binding of importedBindings) {
+    if (!acceptedExports.has(binding)) {
+      return false
+    }
+  }
+  return true
+}
+
 function propagateUpdate(
   node: ModuleNode,
   boundaries: Set<{
@@ -233,18 +245,30 @@ function propagateUpdate(
     return false
   }
 
-  if (!node.importers.size) {
-    return true
-  }
+  // A partially accepted module with no importers is considered self accepting,
+  // because the deal is "there are parts of myself I can't self accept if they
+  // are used outside of me".
+  // Also, the imported module (this one) must be updated before the importers,
+  // so that they do get the fresh imported module when/if they are reloaded.
+  if (node.acceptedHmrExports) {
+    boundaries.add({
+      boundary: node,
+      acceptedVia: node
+    })
+  } else {
+    if (!node.importers.size) {
+      return true
+    }
 
-  // #3716, #3913
-  // For a non-CSS file, if all of its importers are CSS files (registered via
-  // PostCSS plugins) it should be considered a dead end and force full reload.
-  if (
-    !isCSSRequest(node.url) &&
-    [...node.importers].every((i) => isCSSRequest(i.url))
-  ) {
-    return true
+    // #3716, #3913
+    // For a non-CSS file, if all of its importers are CSS files (registered via
+    // PostCSS plugins) it should be considered a dead end and force full reload.
+    if (
+      !isCSSRequest(node.url) &&
+      [...node.importers].every((i) => isCSSRequest(i.url))
+    ) {
+      return true
+    }
   }
 
   for (const importer of node.importers) {
@@ -257,6 +281,16 @@ function propagateUpdate(
       continue
     }
 
+    if (node.id && node.acceptedHmrExports && importer.importedBindings) {
+      const importedBindingsFromNode = importer.importedBindings.get(node.id)
+      if (
+        importedBindingsFromNode &&
+        areAllImportsAccepted(importedBindingsFromNode, node.acceptedHmrExports)
+      ) {
+        continue
+      }
+    }
+
     if (currentChain.includes(importer)) {
       // circular deps is considered dead end
       return true
@@ -423,6 +457,19 @@ export function lexAcceptedHmrDeps(
   return false
 }
 
+export function lexAcceptedHmrExports(
+  code: string,
+  start: number,
+  exportNames: Set<string>
+): boolean {
+  const urls = new Set<{ url: string; start: number; end: number }>()
+  lexAcceptedHmrDeps(code, start, urls)
+  for (const { url } of urls) {
+    exportNames.add(url)
+  }
+  return urls.size > 0
+}
+
 function error(pos: number) {
   const err = new Error(
     `import.meta.hot.accept() can only accept string literals or an ` +