Repository: webpack-contrib/copy-webpack-plugin (js)

Issue:
After each code change, the copy operation of the "copy-webpack-plugin" plug-in is executed at the same time as the recompilation operation.
webpack: v4.43.0
webpack-dev-server: v3.11.0
copy-webpack-plugin: v6.0.2
html-webpack-plugin v4.3.0
Windows 10 professional edition 1902 18363.900
node.js: v14.4.0
npm: v6.14.5

Describe the bug:
1、
After each code change, the copy operation of the "copy-webpack-plugin" plug-in is executed at the same time as the recompilation operation.
![image](https://user-images.githubusercontent.com/12012671/84560498-6bd42480-ad77-11ea-99e3-3c619292c512.png)

To Reproduce:
1、The configuration of "copy-webpack-plugin" is:
![image](https://user-images.githubusercontent.com/12012671/84560514-adfd6600-ad77-11ea-91f1-48aaac850431.png)
2、The configuration of "html-webpack-plugin" is:
![image](https://user-images.githubusercontent.com/12012671/84560600-3c71e780-ad78-11ea-9726-5bc75928e36a.png)
3、The configuration of "webpack" is:
![image](https://user-images.githubusercontent.com/12012671/84560630-704d0d00-ad78-11ea-9e39-fb5b5c54d55f.png)

Expected behavior：
1、
After each code change, the recompile operation will not be executed at the same time as the "copy-webpack-plugin" plugin's copy operation.
2、
The "copy-webpack-plugin" plug-in will be re copied only when the copied file changes.


---

This issue was moved from webpack/webpack#11032 by @evilebottnawi. Original issue was by @LP1994.



Pull request:
feat: persistent cache between runs (webpack@5 only)
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This PR contains a:

- [ ] **bugfix**
- [x] new **feature**
- [x] **code refactor**
- [x] **test update** <!-- if bug or feature is checked, this should be too -->
- [ ] **typo fix**
- [x] **metadata update**

### Motivation / Use-Case

fixes #504 

### Breaking Changes

No

### Additional Info

only webpack@5

Patch:
diff --git a/.gitignore b/.gitignore
index 3162bc4..82f19b2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,6 +9,7 @@ npm-debug.log*
 /reports
 /node_modules
 /test/fixtures/\[special\$directory\]
+/test/outputs
 
 .DS_Store
 Thumbs.db
diff --git a/src/index.js b/src/index.js
index fb9e8aa..9ece267 100644
--- a/src/index.js
+++ b/src/index.js
@@ -37,8 +37,58 @@ class CopyPlugin {
     this.options = options.options || {};
   }
 
+  static async createSnapshot(compilation, startTime, dependency) {
+    if (!compilation.fileSystemInfo) {
+      return;
+    }
+
+    // eslint-disable-next-line consistent-return
+    return new Promise((resolve, reject) => {
+      compilation.fileSystemInfo.createSnapshot(
+        startTime,
+        [dependency],
+        // eslint-disable-next-line no-undefined
+        undefined,
+        // eslint-disable-next-line no-undefined
+        undefined,
+        null,
+        (error, snapshot) => {
+          if (error) {
+            reject(error);
+
+            return;
+          }
+
+          resolve(snapshot);
+        }
+      );
+    });
+  }
+
+  static async checkSnapshotValid(compilation, snapshot) {
+    if (!compilation.fileSystemInfo) {
+      return;
+    }
+
+    // eslint-disable-next-line consistent-return
+    return new Promise((resolve, reject) => {
+      compilation.fileSystemInfo.checkSnapshotValid(
+        snapshot,
+        (error, isValid) => {
+          if (error) {
+            reject(error);
+
+            return;
+          }
+
+          resolve(isValid);
+        }
+      );
+    });
+  }
+
   // eslint-disable-next-line class-methods-use-this
-  async runPattern(compiler, compilation, logger, inputPattern) {
+  static async runPattern(compiler, compilation, logger, cache, inputPattern) {
     const pattern =
       typeof inputPattern === 'string'
         ? { from: inputPattern }
@@ -49,7 +99,6 @@ class CopyPlugin {
     pattern.to = path.normalize(
       typeof pattern.to !== 'undefined' ? pattern.to : ''
     );
-
     pattern.context = path.normalize(
       typeof pattern.context !== 'undefined'
         ? !path.isAbsolute(pattern.context)
@@ -266,64 +315,109 @@ class CopyPlugin {
           compilation.fileDependencies.add(file.absoluteFrom);
         }
 
-        logger.debug(`reading "${file.absoluteFrom}" to write to assets`);
+        let source;
 
-        let data;
+        if (cache) {
+          const cacheEntry = await cache.getPromise(file.relativeFrom, null);
 
-        try {
-          data = await readFile(inputFileSystem, file.absoluteFrom);
-        } catch (error) {
-          compilation.errors.push(error);
+          if (cacheEntry) {
+            const isValidSnapshot = await CopyPlugin.checkSnapshotValid(
+              compilation,
+              cacheEntry.snapshot
+            );
 
-          return;
+            if (isValidSnapshot) {
+              ({ source } = cacheEntry);
+            }
+          }
         }
 
-        if (pattern.transform) {
-          logger.log(`transforming content for "${file.absoluteFrom}"`);
-
-          if (pattern.cacheTransform) {
-            const cacheDirectory = pattern.cacheTransform.directory
-              ? pattern.cacheTransform.directory
-              : typeof pattern.cacheTransform === 'string'
-              ? pattern.cacheTransform
-              : findCacheDir({ name: 'copy-webpack-plugin' }) || os.tmpdir();
-            let defaultCacheKeys = {
-              version,
-              transform: pattern.transform,
-              contentHash: crypto.createHash('md4').update(data).digest('hex'),
-            };
-
-            if (typeof pattern.cacheTransform.keys === 'function') {
-              defaultCacheKeys = await pattern.cacheTransform.keys(
-                defaultCacheKeys,
-                file.absoluteFrom
-              );
-            } else {
-              defaultCacheKeys = {
-                ...defaultCacheKeys,
-                ...pattern.cacheTransform.keys,
+        if (!source) {
+          let startTime;
+
+          if (cache) {
+            startTime = Date.now();
+          }
+
+          logger.debug(`reading "${file.absoluteFrom}" to write to assets`);
+
+          let data;
+
+          try {
+            data = await readFile(inputFileSystem, file.absoluteFrom);
+          } catch (error) {
+            compilation.errors.push(error);
+
+            return;
+          }
+
+          if (pattern.transform) {
+            logger.log(`transforming content for "${file.absoluteFrom}"`);
+
+            if (pattern.cacheTransform) {
+              const cacheDirectory = pattern.cacheTransform.directory
+                ? pattern.cacheTransform.directory
+                : typeof pattern.cacheTransform === 'string'
+                ? pattern.cacheTransform
+                : findCacheDir({ name: 'copy-webpack-plugin' }) || os.tmpdir();
+              let defaultCacheKeys = {
+                version,
+                transform: pattern.transform,
+                contentHash: crypto
+                  .createHash('md4')
+                  .update(data)
+                  .digest('hex'),
               };
-            }
 
-            const cacheKeys = serialize(defaultCacheKeys);
+              if (typeof pattern.cacheTransform.keys === 'function') {
+                defaultCacheKeys = await pattern.cacheTransform.keys(
+                  defaultCacheKeys,
+                  file.absoluteFrom
+                );
+              } else {
+                defaultCacheKeys = {
+                  ...defaultCacheKeys,
+                  ...pattern.cacheTransform.keys,
+                };
+              }
 
-            try {
-              const result = await cacache.get(cacheDirectory, cacheKeys);
+              const cacheKeys = serialize(defaultCacheKeys);
 
-              logger.debug(
-                `getting cached transformation for "${file.absoluteFrom}"`
-              );
+              try {
+                const result = await cacache.get(cacheDirectory, cacheKeys);
 
-              ({ data } = result);
-            } catch (_ignoreError) {
-              data = await pattern.transform(data, file.absoluteFrom);
+                logger.debug(
+                  `getting cached transformation for "${file.absoluteFrom}"`
+                );
 
-              logger.debug(`caching transformation for "${file.absoluteFrom}"`);
+                ({ data } = result);
+              } catch (_ignoreError) {
+                data = await pattern.transform(data, file.absoluteFrom);
+
+                logger.debug(
+                  `caching transformation for "${file.absoluteFrom}"`
+                );
 
-              await cacache.put(cacheDirectory, cacheKeys, data);
+                await cacache.put(cacheDirectory, cacheKeys, data);
+              }
+            } else {
+              data = await pattern.transform(data, file.absoluteFrom);
             }
-          } else {
-            data = await pattern.transform(data, file.absoluteFrom);
+          }
+
+          source = new RawSource(data);
+
+          if (cache) {
+            const snapshot = await CopyPlugin.createSnapshot(
+              compilation,
+              startTime,
+              file.relativeFrom
+            );
+
+            await cache.storePromise(file.relativeFrom, null, {
+              source,
+              snapshot,
+            });
           }
         }
 
@@ -349,7 +443,7 @@ class CopyPlugin {
             { resourcePath: file.absoluteFrom },
             file.webpackTo,
             {
-              content: data,
+              content: source.source(),
               context: pattern.context,
             }
           );
@@ -374,7 +468,7 @@ class CopyPlugin {
         }
 
         // eslint-disable-next-line no-param-reassign
-        file.data = data;
+        file.source = source;
         // eslint-disable-next-line no-param-reassign
         file.targetPath = normalizePath(file.webpackTo);
         // eslint-disable-next-line no-param-reassign
@@ -392,6 +486,10 @@ class CopyPlugin {
 
     compiler.hooks.thisCompilation.tap(pluginName, (compilation) => {
       const logger = compilation.getLogger('copy-webpack-plugin');
+      const cache = compilation.getCache
+        ? compilation.getCache('CopyWebpackPlugin')
+        : // eslint-disable-next-line no-undefined
+          undefined;
 
       compilation.hooks.additionalAssets.tapAsync(
         'copy-webpack-plugin',
@@ -404,7 +502,13 @@ class CopyPlugin {
             assets = await Promise.all(
               this.patterns.map((item) =>
                 limit(async () =>
-                  this.runPattern(compiler, compilation, logger, item)
+                  CopyPlugin.runPattern(
+                    compiler,
+                    compilation,
+                    logger,
+                    cache,
+                    item
+                  )
                 )
               )
             );
@@ -426,12 +530,10 @@ class CopyPlugin {
                 absoluteFrom,
                 targetPath,
                 webpackTo,
-                data,
+                source,
                 force,
               } = asset;
 
-              const source = new RawSource(data);
-
               // For old version webpack 4
               /* istanbul ignore if */
               if (typeof compilation.emitAsset !== 'function') {


Test patch:
diff --git a/test/CopyPlugin.test.js b/test/CopyPlugin.test.js
index f7273a7..898f060 100644
--- a/test/CopyPlugin.test.js
+++ b/test/CopyPlugin.test.js
@@ -1,6 +1,7 @@
 import path from 'path';
 
 import webpack from 'webpack';
+import del from 'del';
 
 import CopyPlugin from '../src';
 
@@ -633,9 +634,72 @@ describe('CopyPlugin', () => {
         .then(done)
         .catch(done);
     });
+  });
+
+  describe('cache', () => {
+    it('should work with the "memory" cache', async () => {
+      const compiler = getCompiler({
+        cache: {
+          type: 'memory',
+        },
+      });
+
+      new CopyPlugin({
+        patterns: [
+          {
+            from: path.resolve(__dirname, './fixtures/directory'),
+          },
+        ],
+      }).apply(compiler);
+
+      const { stats } = await compile(compiler);
+
+      if (webpack.version[0] === '4') {
+        expect(
+          Object.keys(stats.compilation.assets).filter(
+            (assetName) => stats.compilation.assets[assetName].emitted
+          ).length
+        ).toBe(5);
+      } else {
+        expect(stats.compilation.emittedAssets.size).toBe(5);
+      }
+
+      expect(readAssets(compiler, stats)).toMatchSnapshot('assets');
+      expect(stats.compilation.errors).toMatchSnapshot('errors');
+      expect(stats.compilation.warnings).toMatchSnapshot('warnings');
+
+      await new Promise(async (resolve) => {
+        const { stats: newStats } = await compile(compiler);
+
+        if (webpack.version[0] === '4') {
+          expect(
+            Object.keys(newStats.compilation.assets).filter(
+              (assetName) => newStats.compilation.assets[assetName].emitted
+            ).length
+          ).toBe(4);
+        } else {
+          expect(newStats.compilation.emittedAssets.size).toBe(0);
+        }
 
-    it('should work and do not emit unchanged assets', async () => {
-      const compiler = getCompiler();
+        expect(readAssets(compiler, newStats)).toMatchSnapshot('assets');
+        expect(newStats.compilation.errors).toMatchSnapshot('errors');
+        expect(newStats.compilation.warnings).toMatchSnapshot('warnings');
+
+        resolve();
+      });
+    });
+
+    it('should work with the "filesystem" cache', async () => {
+      const cacheDirectory = path.resolve(__dirname, './outputs/.cache');
+
+      await del(cacheDirectory);
+
+      const compiler = getCompiler({
+        cache: {
+          type: 'filesystem',
+          cacheDirectory,
+        },
+      });
 
       new CopyPlugin({
         patterns: [
@@ -671,7 +735,7 @@ describe('CopyPlugin', () => {
             ).length
           ).toBe(4);
         } else {
-          expect(newStats.compilation.emittedAssets.size).toBe(4);
+          expect(newStats.compilation.emittedAssets.size).toBe(0);
         }
 
         expect(readAssets(compiler, newStats)).toMatchSnapshot('assets');
diff --git a/test/__snapshots__/CopyPlugin.test.js.snap b/test/__snapshots__/CopyPlugin.test.js.snap
index 4c768dc..9f77923 100644
--- a/test/__snapshots__/CopyPlugin.test.js.snap
+++ b/test/__snapshots__/CopyPlugin.test.js.snap
@@ -1,5 +1,61 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`CopyPlugin cache should work with the "filesystem" cache: assets 1`] = `
+Object {
+  ".dottedfile": "dottedfile contents
+",
+  "directoryfile.txt": "new",
+  "nested/deep-nested/deepnested.txt": "",
+  "nested/nestedfile.txt": "",
+}
+`;
+
+exports[`CopyPlugin cache should work with the "filesystem" cache: assets 2`] = `
+Object {
+  ".dottedfile": "dottedfile contents
+",
+  "directoryfile.txt": "new",
+  "nested/deep-nested/deepnested.txt": "",
+  "nested/nestedfile.txt": "",
+}
+`;
+
+exports[`CopyPlugin cache should work with the "filesystem" cache: errors 1`] = `Array []`;
+
+exports[`CopyPlugin cache should work with the "filesystem" cache: errors 2`] = `Array []`;
+
+exports[`CopyPlugin cache should work with the "filesystem" cache: warnings 1`] = `Array []`;
+
+exports[`CopyPlugin cache should work with the "filesystem" cache: warnings 2`] = `Array []`;
+
+exports[`CopyPlugin cache should work with the "memory" cache: assets 1`] = `
+Object {
+  ".dottedfile": "dottedfile contents
+",
+  "directoryfile.txt": "new",
+  "nested/deep-nested/deepnested.txt": "",
+  "nested/nestedfile.txt": "",
+}
+`;
+
+exports[`CopyPlugin cache should work with the "memory" cache: assets 2`] = `
+Object {
+  ".dottedfile": "dottedfile contents
+",
+  "directoryfile.txt": "new",
+  "nested/deep-nested/deepnested.txt": "",
+  "nested/nestedfile.txt": "",
+}
+`;
+
+exports[`CopyPlugin cache should work with the "memory" cache: errors 1`] = `Array []`;
+
+exports[`CopyPlugin cache should work with the "memory" cache: errors 2`] = `Array []`;
+
+exports[`CopyPlugin cache should work with the "memory" cache: warnings 1`] = `Array []`;
+
+exports[`CopyPlugin cache should work with the "memory" cache: warnings 2`] = `Array []`;
+
 exports[`CopyPlugin logging should logging when "from" is a directory: logs 1`] = `
 Object {
   "logs": Array [
@@ -76,31 +132,3 @@ Object {
   ],
 }
 `;
-
-exports[`CopyPlugin watch mode should work and do not emit unchanged assets: assets 1`] = `
-Object {
-  ".dottedfile": "dottedfile contents
-",
-  "directoryfile.txt": "new",
-  "nested/deep-nested/deepnested.txt": "",
-  "nested/nestedfile.txt": "",
-}
-`;
-
-exports[`CopyPlugin watch mode should work and do not emit unchanged assets: assets 2`] = `
-Object {
-  ".dottedfile": "dottedfile contents
-",
-  "directoryfile.txt": "new",
-  "nested/deep-nested/deepnested.txt": "",
-  "nested/nestedfile.txt": "",
-}
-`;
-
-exports[`CopyPlugin watch mode should work and do not emit unchanged assets: errors 1`] = `Array []`;
-
-exports[`CopyPlugin watch mode should work and do not emit unchanged assets: errors 2`] = `Array []`;
-
-exports[`CopyPlugin watch mode should work and do not emit unchanged assets: warnings 1`] = `Array []`;
-
-exports[`CopyPlugin watch mode should work and do not emit unchanged assets: warnings 2`] = `Array []`;