Adding conformance webpack plugin

packages/next/build/webpack-config.ts

@@ -44,6 +44,9 @@ import { ProfilingPlugin } from './webpack/plugins/profiling-plugin'
 import { ReactLoadablePlugin } from './webpack/plugins/react-loadable-plugin'
 import { ServerlessPlugin } from './webpack/plugins/serverless-plugin'
 import { TerserPlugin } from './webpack/plugins/terser-webpack-plugin/src/index'
+import WebpackConformancePlugin, {
+  MinificationConformanceCheck,
+} from './webpack/plugins/webpack-conformance-plugin'
 
 type ExcludesFalse = <T>(x: T | false) => x is T
 
@@ -825,6 +828,11 @@ export default async function getBaseWebpackConfig(
           chunkFilename: (inputChunkName: string) =>
             inputChunkName.replace(/\.js$/, '.module.js'),
         }),
+      config.experimental.conformance &&
+        !dev &&
+        new WebpackConformancePlugin({
+          tests: [new MinificationConformanceCheck()],
+        }),
     ].filter((Boolean as any) as ExcludesFalse),
   }
 

packages/next/build/webpack/plugins/webpack-conformance-plugin/TestInterface.ts

@@ -0,0 +1,36 @@
+import { NodePath } from 'ast-types/lib/node-path'
+
+export interface IConformanceAnomaly {
+  message: string
+  stack_trace?: string
+}
+
+export enum IConformanceTestStatus {
+  SUCCESS,
+  FAILED,
+}
+export interface IConformanceTestResult {
+  result: IConformanceTestStatus
+  warnings?: Array<IConformanceAnomaly>
+  errors?: Array<IConformanceAnomaly>
+}
+
+export interface IParsedModuleDetails {
+  request: string
+}
+
+export type NodeInspector = (
+  node: NodePath,
+  details: IParsedModuleDetails
+) => IConformanceTestResult
+
+export interface IGetAstNodeResult {
+  visitor: string
+  inspectNode: NodeInspector
+}
+
+export interface IWebpackConformanceTest {
+  buildStared?: (options: any) => IConformanceTestResult
+  getAstNode?: () => IGetAstNodeResult[]
+  buildCompleted?: (assets: any) => IConformanceTestResult
+}

packages/next/build/webpack/plugins/webpack-conformance-plugin/checks/minification-conformance-check.ts

@@ -0,0 +1,27 @@
+import {
+  IWebpackConformanceTest,
+  IConformanceTestResult,
+  IConformanceTestStatus,
+} from '../TestInterface'
+import { CONFORMANCE_ERROR_PREFIX } from '../constants'
+
+export class MinificationConformanceCheck implements IWebpackConformanceTest {
+  public buildStared(options: any): IConformanceTestResult {
+    // TODO(prateekbh@): Implement warning for using Terser maybe?
+
+    if (options.optimization.minimize === false) {
+      return {
+        result: IConformanceTestStatus.FAILED,
+        errors: [
+          {
+            message: `${CONFORMANCE_ERROR_PREFIX}: Minification is disabled for this build.\nDisabling minification can result in serious performance degradation.`,
+          },
+        ],
+      }
+    } else {
+      return {
+        result: IConformanceTestStatus.SUCCESS,
+      }
+    }
+  }
+}

packages/next/build/webpack/plugins/webpack-conformance-plugin/constants.ts

@@ -0,0 +1,8 @@
+import chalk from 'chalk'
+
+const { red, yellow } = chalk
+
+export const CONFORMANCE_ERROR_PREFIX: string = red('[BUILD CONFORMANCE ERROR]')
+export const CONFORMANCE_WARNING_PREFIX: string = yellow(
+  '[BUILD CONFORMANCE WARNING]'
+)

packages/next/build/webpack/plugins/webpack-conformance-plugin/index.ts

@@ -0,0 +1,149 @@
+import { Compiler, compilation } from 'webpack'
+import {
+  IConformanceTestResult,
+  IWebpackConformanceTest,
+  IConformanceAnomaly,
+  IGetAstNodeResult,
+  NodeInspector,
+  IConformanceTestStatus,
+} from './TestInterface'
+import { NodePath } from 'ast-types/lib/node-path'
+import { visit } from 'recast'
+
+export { MinificationConformanceCheck } from './checks/minification-conformance-check'
+// export { ReactSyncScriptsConformanceTest } from './tests/react-sync-scripts-conformance';
+
+export interface IWebpackConformancePluginOptions {
+  tests: IWebpackConformanceTest[]
+}
+
+interface VisitorMap {
+  [key: string]: (path: NodePath) => void
+}
+
+export default class WebpackConformancePlugin {
+  private tests: IWebpackConformanceTest[]
+  private errors: Array<IConformanceAnomaly>
+  private warnings: Array<IConformanceAnomaly>
+  private compiler?: Compiler
+
+  constructor(options: IWebpackConformancePluginOptions) {
+    this.tests = []
+    if (options.tests) {
+      this.tests.push(...options.tests)
+    }
+    this.errors = []
+    this.warnings = []
+  }
+
+  private gatherResults(results: Array<IConformanceTestResult>): void {
+    results.forEach(result => {
+      if (result.result === 'FAILED') {
+        result.errors && this.errors.push(...result.errors)
+        result.warnings && this.warnings.push(...result.warnings)
+      }
+    })
+  }
+
+  private buildStartedHandler = (
+    compilation: compilation.Compilation,
+    callback: () => void
+  ) => {
+    const buildStartedResults: IConformanceTestResult[] = this.tests.map(
+      test => {
+        if (test.buildStared && this.compiler) {
+          return test.buildStared(this.compiler.options)
+        }
+        return {
+          result: IConformanceTestStatus.SUCCESS,
+        } as IConformanceTestResult
+      }
+    )
+
+    this.gatherResults(buildStartedResults)
+    callback()
+  }
+
+  private buildCompletedHandler = (
+    compilation: compilation.Compilation,
+    cb: () => void
+  ): void => {
+    const buildCompletedResults: IConformanceTestResult[] = this.tests.map(
+      test => {
+        if (test.buildCompleted) {
+          return test.buildCompleted(compilation.assets)
+        }
+        return {
+          result: IConformanceTestStatus.SUCCESS,
+        } as IConformanceTestResult
+      }
+    )
+
+    this.gatherResults(buildCompletedResults)
+    compilation.errors.push(...this.errors)
+    compilation.warnings.push(...this.warnings)
+    cb()
+  }
+
+  private parserHandler = (factory: compilation.NormalModuleFactory): void => {
+    const JS_TYPES = ['auto', 'esm', 'dynamic']
+    const collectedVisitors: Map<string, [NodeInspector?]> = new Map()
+    // Collect all intereseted visitors from all tests.
+    this.tests.forEach(test => {
+      if (test.getAstNode) {
+        const getAstNodeCallbacks: IGetAstNodeResult[] = test.getAstNode()
+        getAstNodeCallbacks.forEach(result => {
+          if (!collectedVisitors.has(result.visitor)) {
+            collectedVisitors.set(result.visitor, [])
+          }
+          // @ts-ignore
+          collectedVisitors.get(result.visitor).push(result.inspectNode)
+        })
+      }
+    })
+
+    // Do an extra walk per module and add interested visitors to the walk.
+    for (const type of JS_TYPES) {
+      factory.hooks.parser
+        .for('javascript/' + type)
+        .tap(this.constructor.name, parser => {
+          parser.hooks.program.tap(this.constructor.name, (ast: any) => {
+            const visitors: VisitorMap = {}
+            const that = this
+            for (const visitorKey of collectedVisitors.keys()) {
+              visitors[visitorKey] = function(path: NodePath) {
+                const callbacks = collectedVisitors.get(visitorKey) || []
+                callbacks.forEach(cb => {
+                  if (!cb) {
+                    return
+                  }
+                  const { request } = parser.state.module
+                  const outcome = cb(path, { request })
+                  that.gatherResults([outcome])
+                })
+                this.traverse(path)
+                return false
+              }
+            }
+            visit(ast, visitors)
+          })
+        })
+    }
+  }
+
+  public apply(compiler: Compiler) {
+    this.compiler = compiler
+    compiler.hooks.make.tapAsync(
+      this.constructor.name,
+      this.buildStartedHandler
+    )
+    compiler.hooks.emit.tapAsync(
+      this.constructor.name,
+      this.buildCompletedHandler
+    )
+    compiler.hooks.normalModuleFactory.tap(
+      this.constructor.name,
+      this.parserHandler
+    )
+  }
+}

packages/next/package.json

@@ -122,6 +122,7 @@
     "raw-body": "2.4.0",
     "react-error-overlay": "5.1.6",
     "react-is": "16.8.6",
+    "recast": "0.18.5",
     "resolve-url-loader": "3.1.1",
     "sass-loader": "8.0.2",
     "send": "0.17.1",
@@ -185,6 +186,7 @@
     "@types/webpack-sources": "0.1.5",
     "@zeit/ncc": "0.18.5",
     "arg": "4.1.0",
+    "ast-types": "0.13.2",
     "babel-plugin-dynamic-import-node": "2.3.0",
     "nanoid": "2.0.3",
     "resolve": "1.11.0",

yarn.lock

@@ -3395,6 +3395,11 @@ assign-symbols@^1.0.0:
   resolved "https://registry.yarnpkg.com/assign-symbols/-/assign-symbols-1.0.0.tgz#59667f41fadd4f20ccbc2bb96b8d4f7f78ec0367"
   integrity sha1-WWZ/QfrdTyDMvCu5a41Pf3jsA2c=
 
+ast-types@0.13.2:
+  version "0.13.2"
+  resolved "https://registry.yarnpkg.com/ast-types/-/ast-types-0.13.2.tgz#df39b677a911a83f3a049644fb74fdded23cea48"
+  integrity sha512-uWMHxJxtfj/1oZClOxDEV1sQ1HCDkA4MG8Gr69KKeBjEVH0R84WlejZ0y2DcwyBlpAEMltmVYkVgqfLFb2oyiA==
+
 astral-regex@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/astral-regex/-/astral-regex-1.0.0.tgz#6c8c3fb827dd43ee3918f27b82782ab7658a6fd9"
@@ -6072,7 +6077,7 @@ esprima@^3.1.3:
   resolved "https://registry.yarnpkg.com/esprima/-/esprima-3.1.3.tgz#fdca51cee6133895e3c88d535ce49dbff62a4633"
   integrity sha1-/cpRzuYTOJXjyI1TXOSdv/YqRjM=
 
-esprima@^4.0.0:
+esprima@^4.0.0, esprima@~4.0.0:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/esprima/-/esprima-4.0.1.tgz#13b04cdb3e6c5d19df91ab6987a8695619b0aa71"
   integrity sha512-eGuFFw7Upda+g4p+QHvnW0RyTX/SVeJBDM/gCtMARO0cLuT2HcEKnTPvhjV6aGeqrCB/sbNop0Kszm0jsaWU4A==
@@ -12230,7 +12235,7 @@ pretty-hrtime@^1.0.3:
   resolved "https://registry.yarnpkg.com/pretty-hrtime/-/pretty-hrtime-1.0.3.tgz#b7e3ea42435a4c9b2759d99e0f201eb195802ee1"
   integrity sha1-t+PqQkNaTJsnWdmeDyAesZWALuE=
 
-private@^0.1.6:
+private@^0.1.6, private@^0.1.8:
   version "0.1.8"
   resolved "https://registry.yarnpkg.com/private/-/private-0.1.8.tgz#2381edb3689f7a53d653190060fcf822d2f368ff"
   integrity sha512-VvivMrbvd2nKkiG38qjULzlc+4Vx4wm/whI9pQD35YrARNnhxeiRktSOhSukRLFNlzg6Br/cJPet5J/u19r/mg==
@@ -12753,6 +12758,16 @@ realpath-native@^1.1.0:
   dependencies:
     util.promisify "^1.0.0"
 
+recast@0.18.5:
+  version "0.18.5"
+  resolved "https://registry.yarnpkg.com/recast/-/recast-0.18.5.tgz#9d5adbc07983a3c8145f3034812374a493e0fe4d"
+  integrity sha512-sD1WJrpLQAkXGyQZyGzTM75WJvyAd98II5CHdK3IYbt/cZlU0UzCRVU11nUFNXX9fBVEt4E9ajkMjBlUlG+Oog==
+  dependencies:
+    ast-types "0.13.2"
+    esprima "~4.0.0"
+    private "^0.1.8"
+    source-map "~0.6.1"
+
 redent@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/redent/-/redent-1.0.0.tgz#cf916ab1fd5f1f16dfb20822dd6ec7f730c2afde"