From ff90a3ab44117c65e3ecd2d35030f1d81ca5e187 Mon Sep 17 00:00:00 2001
From: Christian Mortaro <christian.mortaro@gmail.com>
Date: Sat, 4 Mar 2023 17:01:25 -0300
Subject: [PATCH] fix: add writeToDisk support for clean: true

---
 src/index.js                        |  4 +--
 src/utils/setupWriteToDisk.js       | 14 +++++++++
 test/utils/setupWriteToDisk.test.js | 44 +++++++++++++++++++++++++++++
 3 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/src/index.js b/src/index.js
index 0d6d6dec0..92760a763 100644
--- a/src/index.js
+++ b/src/index.js
@@ -183,12 +183,12 @@ function wdm(compiler, options = {}) {
 
   setupHooks(context);
 
+  setupOutputFileSystem(context);
+
   if (options.writeToDisk) {
     setupWriteToDisk(context);
   }
 
-  setupOutputFileSystem(context);
-
   // Start watching
   if (/** @type {Compiler} */ (context.compiler).watching) {
     context.watching = /** @type {Compiler} */ (context.compiler).watching;
diff --git a/src/utils/setupWriteToDisk.js b/src/utils/setupWriteToDisk.js
index 4ac3af302..1a9caebc3 100644
--- a/src/utils/setupWriteToDisk.js
+++ b/src/utils/setupWriteToDisk.js
@@ -21,6 +21,20 @@ function setupWriteToDisk(context) {
     (context.compiler).compilers || [context.compiler];
 
   for (const compiler of compilers) {
+    if (compiler.outputFileSystem && compiler.options.output.clean) {
+      /** @type {Compiler["outputFileSystem"]} */
+      const { unlink: originalUnlink } = compiler.outputFileSystem;
+      if (originalUnlink) {
+        compiler.outputFileSystem.unlink = (
+          /** @type {String} */ originalPath,
+          /** @type {(arg0?: null | NodeJS.ErrnoException) => void} */ originalCallback
+        ) => {
+          fs.unlink(originalPath, () => {});
+          originalUnlink(originalPath, originalCallback);
+        };
+      }
+    }
+
     compiler.hooks.emit.tap(
       "DevMiddleware",
       /**
diff --git a/test/utils/setupWriteToDisk.test.js b/test/utils/setupWriteToDisk.test.js
index 74a281609..e409d013f 100644
--- a/test/utils/setupWriteToDisk.test.js
+++ b/test/utils/setupWriteToDisk.test.js
@@ -5,6 +5,7 @@ import setupWriteToDisk from "../../src/utils/setupWriteToDisk";
 
 const mkdirSpy = jest.spyOn(fs, "mkdir");
 const writeFileSpy = jest.spyOn(fs, "writeFile");
+const unlinkFileSpy = jest.spyOn(fs, "unlink");
 
 describe("setupWriteToDisk", () => {
   let context;
@@ -41,6 +42,7 @@ describe("setupWriteToDisk", () => {
     getPath.mockClear();
     mkdirSpy.mockClear();
     writeFileSpy.mockClear();
+    unlinkFileSpy.mockClear();
   });
 
   const runAssetEmitted = (...args) => {
@@ -180,4 +182,46 @@ describe("setupWriteToDisk", () => {
       expect(cb.mock.calls).toMatchSnapshot();
     });
   });
+
+  const cleanOptions = [
+    {
+      title: "true",
+      value: true,
+    },
+    {
+      title: "false",
+      value: false,
+    },
+    {
+      title: "an object",
+      value: { keep: () => true },
+    },
+  ];
+
+  cleanOptions.forEach((cleanOption) => {
+    it(`calls node fs unlink when using memfs and clean is ${cleanOption.title}`, (done) => {
+      const unlink = jest.fn((_, callback) => callback());
+      context.compiler.outputFileSystem = { unlink };
+      context.compiler.options = {
+        output: {
+          clean: cleanOption.value,
+        },
+      };
+      context.options = {
+        writeToDisk: true,
+      };
+      setupWriteToDisk(context);
+
+      context.compiler.outputFileSystem.unlink("/target/path/file", () => {
+        // the memfs unlink should always be called
+        expect(unlink.mock.calls.length).toEqual(1);
+
+        // the fs unlink should be called when the clean value is truthy
+        const expectedCallCount = cleanOption.value ? 1 : 0;
+        expect(unlinkFileSpy.mock.calls.length).toEqual(expectedCallCount);
+
+        done();
+      });
+    });
+  });
 });