fix: ensure unique ident when cloning rules, fix webpack 5 compatibility (#1653)

* chore: lockfile maintenance

* chore: update memfs to ^3.1.2

Fixes a bug in `mkdir('/')`, which causes tests fail to run in webpack 5

* test: setup webpack 5 test

* fix: fix webpack 5 compatibility and add test for it

* ci: fix yaml grammar

Author: haoqunjiang

Diff for: .circleci/config.yml

@@ -27,3 +27,7 @@ jobs:
 
       # run tests!
       - run: yarn test
+
+      - run: npx json -f package.json -I -e "this.resolutions = {}, this.resolutions.webpack = '^5.0.0-0', this.devDependencies.webpack = '^5.0.0-0' "
+      - run: yarn install
+      - run: yarn test

Diff for: lib/plugin-webpack5.js

@@ -128,8 +128,9 @@ class VueLoaderPlugin {
   }
 }
 
+let uid = 0
 function cloneRule (rawRule, refs) {
-  const rules = ruleSetCompiler.compileRules('ruleSet', [{
+  const rules = ruleSetCompiler.compileRules(`clonedRuleSet-${++uid}`, [{
     rules: [rawRule]
   }], refs)
   let currentResource

Diff for: package.json

@@ -66,13 +66,14 @@
     "eslint": "^4.19.0",
     "eslint-plugin-vue-libs": "^2.1.0",
     "file-loader": "^1.1.11",
-    "html-webpack-plugin": "^3.1.0",
+    "html-webpack-plugin": "4.0.0-beta.14",
     "javascript-stringify": "^1.6.0",
     "jest": "^23.5.0",
     "jsdom": "^11.6.2",
+    "json": "^9.0.6",
     "lint-staged": "^7.0.0",
     "markdown-loader": "^2.0.2",
-    "memfs": "^3.0.3",
+    "memfs": "^3.1.2",
     "mini-css-extract-plugin": "^0.4.1",
     "node-sass": "^4.7.2",
     "normalize-newline": "^3.0.0",

Diff for: test/core.spec.js

@@ -144,3 +144,33 @@ test('script import', done => {
     done()
   })
 })
+
+// #1620
+test('cloned rules should not intefere with each other', done => {
+  mockBundleAndRun({
+    entry: 'basic.vue',
+    module: {
+      rules: [{
+        test: /\.js$/,
+        use: [
+          {
+            loader: 'babel-loader',
+            options: {}
+          }
+        ]
+      }, {
+        test: /\.some-random-extension$/,
+        use: [
+          {
+            loader: 'css-loader',
+            options: {
+              url: true
+            }
+          }
+        ]
+      }]
+    }
+  }, () => {
+    done()
+  })
+})

Diff for: test/utils.js

@@ -39,7 +39,11 @@ const baseConfig = {
   plugins: [
     new VueLoaderPlugin(),
     new webpack.optimize.ModuleConcatenationPlugin()
-  ]
+  ],
+  // https://github.com/webpack/webpack/issues/10542
+  optimization: {
+    usedExports: false
+  }
 }
 
 function genId (file) {