fix(runtime): runtime HMR affects only imported files

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

@@ -166,6 +166,7 @@ export async function handleHMRUpdate(
     hot.send({
       type: 'full-reload',
       path: '*',
+      triggeredBy: path.resolve(config.root, file),
     })
     return
   }
@@ -272,6 +273,7 @@ export function updateModules(
     )
     hot.send({
       type: 'full-reload',
+      triggeredBy: path.resolve(config.root, file),
     })
     return
   }
@@ -295,7 +297,7 @@ export function updateModules(
 function populateSSRImporters(
   module: ModuleNode,
   timestamp: number,
-  seen: Set<ModuleNode>,
+  seen: Set<ModuleNode> = new Set(),
 ) {
   module.ssrImportedModules.forEach((importer) => {
     if (seen.has(importer)) {
@@ -313,9 +315,9 @@ function populateSSRImporters(
 }
 
 function getSSRInvalidatedImporters(module: ModuleNode) {
-  return [
-    ...populateSSRImporters(module, module.lastHMRTimestamp, new Set()),
-  ].map((m) => m.file!)
+  return [...populateSSRImporters(module, module.lastHMRTimestamp)].map(
+    (m) => m.file!,
+  )
 }
 
 export async function handleFileAddUnlink(

packages/vite/src/node/ssr/runtime/hmrHandler.ts

@@ -43,18 +43,28 @@ export async function handleHMRPayload(
       await hmrClient.notifyListeners(payload.event, payload.data)
       break
     }
-    case 'full-reload':
+    case 'full-reload': {
+      const { triggeredBy } = payload
+      const clearEntrypoints = triggeredBy
+        ? [...runtime.entrypoints].filter((entrypoint) =>
+            runtime.moduleCache.isImported({
+              importedId: triggeredBy,
+              importedBy: entrypoint,
+            }),
+          )
+        : [...runtime.entrypoints]
+
+      if (!clearEntrypoints.length) break
+
       hmrClient.logger.debug(`[vite] program reload`)
       await hmrClient.notifyListeners('vite:beforeFullReload', payload)
-      Array.from(runtime.moduleCache.keys()).forEach((id) => {
-        if (!id.includes('node_modules')) {
-          runtime.moduleCache.deleteByModuleId(id)
-        }
-      })
-      for (const id of runtime.entrypoints) {
+      runtime.moduleCache.clear()
+
+      for (const id of clearEntrypoints) {
         await runtime.executeUrl(id)
       }
       break
+    }
     case 'prune':
       await hmrClient.notifyListeners('vite:beforePrune', payload)
       hmrClient.prunePaths(payload.paths)

packages/vite/src/node/ssr/runtime/moduleCache.ts

@@ -65,6 +65,57 @@ export class ModuleCacheMap extends Map<string, ModuleCache> {
     return this.deleteByModuleId(this.normalize(fsPath))
   }
 
+  invalidate(id: string): void {
+    const module = this.get(id)
+    module.evaluated = false
+    module.meta = undefined
+    module.map = undefined
+    module.promise = undefined
+    module.exports = undefined
+    // remove imports in case they are changed,
+    // don't remove the importers because otherwise it will be empty after evaluation
+    // this can create a bug when file was removed but it still triggers full-reload
+    // we are fine with the bug for now because it's not a common case
+    module.imports?.clear()
+  }
+
+  isImported(
+    {
+      importedId,
+      importedBy,
+    }: {
+      importedId: string
+      importedBy: string
+    },
+    seen = new Set<string>(),
+  ): boolean {
+    importedId = this.normalize(importedId)
+    importedBy = this.normalize(importedBy)
+
+    if (importedBy === importedId) return true
+
+    if (seen.has(importedId)) return false
+    seen.add(importedId)
+
+    const fileModule = this.getByModuleId(importedId)
+    const importers = fileModule?.importers
+
+    if (!importers) return false
+
+    if (importers.has(importedBy)) return true
+
+    for (const importer of importers) {
+      if (
+        this.isImported({
+          importedBy: importedBy,
+          importedId: importer,
+        })
+      )
+        return true
+    }
+    return false
+  }
+
   /**
    * Invalidate modules that dependent on the given modules, up to the main entry
    */

packages/vite/src/node/ssr/runtime/runtime.ts

@@ -72,7 +72,7 @@ export class ViteRuntime {
           : options.hmr.logger || console,
         options.hmr.connection,
         ({ acceptedPath, ssrInvalidates }) => {
-          this.moduleCache.delete(acceptedPath)
+          this.moduleCache.invalidate(acceptedPath)
           if (ssrInvalidates) {
             this.invalidateFiles(ssrInvalidates)
           }
@@ -140,7 +140,7 @@ export class ViteRuntime {
     files.forEach((file) => {
       const ids = this.fileToIdMap.get(file)
       if (ids) {
-        ids.forEach((id) => this.moduleCache.deleteByModuleId(id))
+        ids.forEach((id) => this.moduleCache.invalidate(id))
       }
     })
   }

packages/vite/types/hmrPayload.d.ts

@@ -36,6 +36,8 @@ export interface PrunePayload {
 export interface FullReloadPayload {
   type: 'full-reload'
   path?: string
+  /** @internal */
+  triggeredBy?: string
 }
 
 export interface CustomPayload {

playground/hmr-ssr/__tests__/hmr.spec.ts

@@ -506,6 +506,55 @@ describe('acceptExports', () => {
         )
       })
     })
+
+    describe("doesn't reload if files not in the the entrypoint importers chain is changed", async () => {
+      const testFile = 'non-tested/index.js'
+
+      beforeAll(async () => {
+        clientLogs.length = 0
+        // so it's in the module graph
+        await server.transformRequest(testFile, { ssr: true })
+        await server.transformRequest('non-tested/dep.js', { ssr: true })
+      })
+
+      test('does not full reload', async () => {
+        editFile(
+          testFile,
+          (code) => code + '\n\nexport const query5 = "query5"',
+        )
+        const start = Date.now()
+        // for 2 seconds check that there is no log about the file being reloaded
+        while (Date.now() - start < 2000) {
+          if (
+            clientLogs.some(
+              (log) =>
+                log.match(PROGRAM_RELOAD) ||
+                log.includes('non-tested/index.js'),
+            )
+          ) {
+            throw new Error('File was reloaded')
+          }
+          await new Promise((r) => setTimeout(r, 100))
+        }
+      }, 5_000)
+
+      test('does not update', async () => {
+        editFile('non-tested/dep.js', (code) => code + '//comment')
+        const start = Date.now()
+        // for 2 seconds check that there is no log about the file being reloaded
+        while (Date.now() - start < 2000) {
+          if (
+            clientLogs.some(
+              (log) =>
+                log.match(PROGRAM_RELOAD) || log.includes('non-tested/dep.js'),
+            )
+          ) {
+            throw new Error('File was updated')
+          }
+          await new Promise((r) => setTimeout(r, 100))
+        }
+      }, 5_000)
+    })
   })
 
   test('accepts itself when imported for side effects only (no bindings imported)', async () => {

playground/hmr-ssr/non-tested/dep.js

@@ -0,0 +1,3 @@
+export const test = 'true'
+
+import.meta.hot.accept()

playground/hmr-ssr/non-tested/index.js

@@ -0,0 +1,9 @@
+import { test } from './dep.js'
+
+function main() {
+  test()
+}
+
+main()
+
+import.meta.hot.accept('./dep.js')