fix(dev): prime mtimes cache when starting dev server

packages/nuxi/src/dev/utils.ts

@@ -7,7 +7,7 @@ import type { FSWatcher } from 'node:fs'
 import type { IncomingMessage, RequestListener, ServerResponse } from 'node:http'
 
 import EventEmitter from 'node:events'
-import { existsSync, statSync, watch } from 'node:fs'
+import { existsSync, readdirSync, statSync, watch } from 'node:fs'
 import { mkdir } from 'node:fs/promises'
 import process from 'node:process'
 import { pathToFileURL } from 'node:url'
@@ -70,22 +70,45 @@ export class FileChangeTracker {
   private mtimes = new Map<string, number>()
 
   shouldEmitChange(filePath: string): boolean {
+    const resolved = resolve(filePath)
     try {
-      const stats = statSync(filePath)
+      const stats = statSync(resolved)
       const currentMtime = stats.mtimeMs
-      const lastMtime = this.mtimes.get(filePath)
+      const lastMtime = this.mtimes.get(resolved)
 
-      this.mtimes.set(filePath, currentMtime)
+      this.mtimes.set(resolved, currentMtime)
 
       // emit change for new file or mtime has changed
       return lastMtime === undefined || currentMtime !== lastMtime
     }
     catch {
       // remove from cache if it has been deleted or is inaccessible
-      this.mtimes.delete(filePath)
+      this.mtimes.delete(resolved)
       return true
     }
   }
+
+  prime(filePath: string, recursive: boolean = false): void {
+    const resolved = resolve(filePath)
+    const stat = statSync(resolved)
+    this.mtimes.set(resolved, stat.mtimeMs)
+    if (stat.isDirectory()) {
+      const entries = readdirSync(resolved)
+      for (const entry of entries) {
+        const fullPath = resolve(resolved, entry)
+        try {
+          const stats = statSync(fullPath)
+          this.mtimes.set(fullPath, stats.mtimeMs)
+          if (recursive && stats.isDirectory()) {
+            this.prime(fullPath, recursive)
+          }
+        }
+        catch {
+          // ignore
+        }
+      }
+    }
+  }
 }
 
 type NuxtWithServer = Omit<Nuxt, 'server'> & { server?: NitroDevServer | ReturnType<typeof createDevServer> }
@@ -414,6 +437,7 @@ export class NuxtDevServer extends EventEmitter<DevServerEventMap> {
     // Watch dist directory
     const distDir = resolve(this.#currentNuxt.options.buildDir, 'dist')
     await mkdir(distDir, { recursive: true })
+    this.#fileChangeTracker.prime(distDir)
     this.#distWatcher = watch(distDir)
     this.#distWatcher.on('change', (_event, file: string) => {
       if (!this.#fileChangeTracker.shouldEmitChange(resolve(distDir, file || ''))) {
@@ -510,10 +534,11 @@ function resolveDevServerDefaults(listenOptions: Partial<Pick<ListenOptions, 'ho
 }
 
 function createConfigWatcher(cwd: string, dotenvFileName: string | string[] = '.env', onRestart: () => void, onReload: (file: string) => void) {
+  const fileWatcher = new FileChangeTracker()
+  fileWatcher.prime(cwd)
   const configWatcher = watch(cwd)
   let configDirWatcher = existsSync(resolve(cwd, '.config')) ? createConfigDirWatcher(cwd, onReload) : undefined
   const dotenvFileNames = new Set(Array.isArray(dotenvFileName) ? dotenvFileName : [dotenvFileName])
-  const fileWatcher = new FileChangeTracker()
 
   configWatcher.on('change', (_event, file: string) => {
     if (!fileWatcher.shouldEmitChange(resolve(cwd, file))) {
@@ -543,6 +568,7 @@ function createConfigDirWatcher(cwd: string, onReload: (file: string) => void) {
   const configDir = resolve(cwd, '.config')
   const fileWatcher = new FileChangeTracker()
 
+  fileWatcher.prime(configDir)
   const configDirWatcher = watch(configDir)
   configDirWatcher.on('change', (_event, file: string) => {
     if (!fileWatcher.shouldEmitChange(resolve(configDir, file))) {

packages/nuxi/test/unit/file-watcher.spec.ts

@@ -1,5 +1,5 @@
 import { existsSync } from 'node:fs'
-import { mkdtemp, rm, utimes, writeFile } from 'node:fs/promises'
+import { mkdir, mkdtemp, rm, utimes, writeFile } from 'node:fs/promises'
 import { tmpdir } from 'node:os'
 import { join } from 'node:path'
 import { afterEach, beforeEach, describe, expect, it } from 'vitest'
@@ -8,12 +8,17 @@ import { FileChangeTracker } from '../../src/dev/utils'
 
 describe('fileWatcher', () => {
   let tempDir: string
+  let tempSubdir: string
   let testFile: string
+  let testSubdirFile: string
   let fileWatcher: FileChangeTracker
 
   beforeEach(async () => {
     tempDir = await mkdtemp(join(tmpdir(), 'nuxt-cli-test-'))
+    tempSubdir = join(tempDir, 'subdir')
+    await mkdir(tempSubdir)
     testFile = join(tempDir, 'test-config.js')
+    testSubdirFile = join(tempSubdir, 'test-subdir-config.js')
     fileWatcher = new FileChangeTracker()
   })
 
@@ -30,6 +35,49 @@ describe('fileWatcher', () => {
     expect(shouldEmit).toBe(true)
   })
 
+  it('should return false for first check of a file if primed', async () => {
+    await writeFile(testFile, 'initial content')
+
+    fileWatcher.prime(testFile)
+    const shouldEmit = fileWatcher.shouldEmitChange(testFile)
+    expect(shouldEmit).toBe(false)
+  })
+
+  it('should return false for first check of nested files if primed in recursive mode', async () => {
+    await writeFile(testFile, 'initial content')
+    await writeFile(testSubdirFile, 'initial content in subdir')
+
+    // Prime the directory in recursive mode
+    fileWatcher.prime(tempDir, true)
+    expect(fileWatcher.shouldEmitChange(testFile)).toBe(false)
+    expect(fileWatcher.shouldEmitChange(testSubdirFile)).toBe(false)
+    expect(fileWatcher.shouldEmitChange(tempDir)).toBe(false)
+    expect(fileWatcher.shouldEmitChange(tempSubdir)).toBe(false)
+  })
+
+  it('should return true for first check of nested files if primed in non-recursive mode', async () => {
+    await writeFile(testFile, 'initial content')
+    await writeFile(testSubdirFile, 'initial content in subdir')
+
+    // Prime the directory in recursive mode
+    fileWatcher.prime(tempDir)
+    expect(fileWatcher.shouldEmitChange(testFile)).toBe(false)
+    expect(fileWatcher.shouldEmitChange(testSubdirFile)).toBe(true)
+    expect(fileWatcher.shouldEmitChange(tempDir)).toBe(false)
+    expect(fileWatcher.shouldEmitChange(tempSubdir)).toBe(false)
+  })
+
+  it('should return false for first check of a file if directory is primed', async () => {
+    await writeFile(testFile, 'initial content')
+
+    fileWatcher.prime(tempDir)
+    const shouldEmit = fileWatcher.shouldEmitChange(testFile)
+    expect(shouldEmit).toBe(false)
+    // Also test the directory itself
+    const dirShouldEmit = fileWatcher.shouldEmitChange(tempDir)
+    expect(dirShouldEmit).toBe(false)
+  })
+
   it('should return false when file has not been modified', async () => {
     await writeFile(testFile, 'initial content')
 
@@ -63,6 +111,27 @@ describe('fileWatcher', () => {
     expect(fileWatcher.shouldEmitChange(testFile)).toBe(false)
   })
 
+  it('should return true only when file has been modified, if primed', async () => {
+    await writeFile(testFile, 'initial content')
+    fileWatcher.prime(testFile)
+
+    // First check
+    expect(fileWatcher.shouldEmitChange(testFile)).toBe(false)
+
+    // No modification - should return false
+    expect(fileWatcher.shouldEmitChange(testFile)).toBe(false)
+
+    // Wait a bit and modify the file
+    await new Promise(resolve => setTimeout(resolve, 10))
+    await writeFile(testFile, 'modified content')
+
+    // Should return true because file was modified
+    expect(fileWatcher.shouldEmitChange(testFile)).toBe(true)
+
+    // Subsequent check without modification should return false
+    expect(fileWatcher.shouldEmitChange(testFile)).toBe(false)
+  })
+
   it('should handle file deletion gracefully', async () => {
     await writeFile(testFile, 'content')
 

packages/nuxt-cli/test/e2e/runtimes.spec.ts

@@ -42,8 +42,8 @@ function createIt(runtimeName: typeof runtimes[number]) {
     const supportMatrix: Record<typeof runtimes[number], SupportStatus> = {
       node: true,
       bun: {
-        start: !platform.windows,
-        fetching: !platform.windows,
+        start: true,
+        fetching: true,
         // https://github.com/nitrojs/nitro/issues/2721
         websockets: false,
       },