Exclude cache from being deleted in dev (#9448)

* Exclude cache from being deleted in dev

* Exclude cache directory from delete

* Fix clean regex and update tests

* Remove extra param comment

packages/next/lib/recursive-delete.ts

@@ -34,22 +34,20 @@ const unlinkFile = async (p: string, t = 1): Promise<void> => {
 /**
  * Recursively delete directory contents
  * @param  {string} dir Directory to delete the contents of
- * @param  {RegExp} [filter] Filter for the relative file path
- * @param  {boolean} [ensure] Ensures that parameter dir exists, this is not passed recursively
+ * @param  {RegExp} [exclude] Exclude based on relative file path
  * @param  {string} [previousPath] Ensures that parameter dir exists, this is not passed recursively
  * @returns Promise void
  */
 export async function recursiveDelete(
   dir: string,
-  filter?: RegExp,
-  previousPath: string = '',
-  ensure?: boolean
+  exclude?: RegExp,
+  previousPath: string = ''
 ): Promise<void> {
   let result
   try {
     result = await readdir(dir)
   } catch (e) {
-    if (e.code === 'ENOENT' && !ensure) {
+    if (e.code === 'ENOENT') {
       return
     }
     throw e
@@ -65,17 +63,13 @@ export async function recursiveDelete(
         return
       }
 
-      if (pathStat.isDirectory()) {
-        const pp = join(previousPath, part)
-        await recursiveDelete(absolutePath, filter, pp)
-
-        if (!filter || filter.test(pp)) {
-          return rmdir(absolutePath)
-        }
-        return
+      const pp = join(previousPath, part)
+      if (pathStat.isDirectory() && (!exclude || !exclude.test(pp))) {
+        await recursiveDelete(absolutePath, exclude, pp)
+        return rmdir(absolutePath)
       }
 
-      if (!filter || filter.test(join(previousPath, part))) {
+      if (!exclude || !exclude.test(pp)) {
         return unlinkFile(absolutePath)
       }
     })

packages/next/server/hot-reloader.ts

@@ -236,7 +236,7 @@ export default class HotReloader {
   }
 
   async clean() {
-    return recursiveDelete(join(this.dir, this.config.distDir))
+    return recursiveDelete(join(this.dir, this.config.distDir), /^cache/)
   }
 
   async getWebpackConfig() {

test/isolated/_resolvedata/cache/test.txt

@@ -0,0 +1 @@
+hello world

test/unit/recursive-delete.test.js

@@ -6,13 +6,38 @@ import { join } from 'path'
 
 const resolveDataDir = join(__dirname, '..', 'isolated', '_resolvedata')
 const testResolveDataDir = join(__dirname, '..', 'isolated', 'test_resolvedata')
+const testpreservefileDir = join(__dirname, '..', 'isolated', 'preservefiles')
 
 describe('recursiveDelete', () => {
   it('should work', async () => {
-    await recursiveCopy(resolveDataDir, testResolveDataDir)
+    expect.assertions(1)
+    try {
+      await recursiveCopy(resolveDataDir, testResolveDataDir)
+      await recursiveDelete(testResolveDataDir)
+      const result = await recursiveReadDir(testResolveDataDir, /.*/)
+      expect(result.length).toBe(0)
+    } finally {
+      await recursiveDelete(testResolveDataDir)
+    }
+  })
 
-    await recursiveDelete(testResolveDataDir)
-    const result = await recursiveReadDir(testResolveDataDir, /.*/)
-    expect(result.length).toBe(0)
+  it('should exclude', async () => {
+    expect.assertions(2)
+    try {
+      await recursiveCopy(resolveDataDir, testpreservefileDir, {
+        overwrite: true,
+      })
+      // preserve cache dir
+      await recursiveDelete(testpreservefileDir, /^cache/)
+
+      const result = await recursiveReadDir(testpreservefileDir, /.*/)
+      expect(result.length).toBe(1)
+    } finally {
+      // Ensure test cleanup
+      await recursiveDelete(testpreservefileDir)
+
+      const cleanupResult = await recursiveReadDir(testpreservefileDir, /.*/)
+      expect(cleanupResult.length).toBe(0)
+    }
   })
 })