Polish webpack message output (#5174)

* Only install react-scripts in CI mode

* Link locally

* Re-enable all output tests

*  Polish webpack output

* Test sass support message

* Add more tests, but disabled

* Format missing default export error

* Format aliased import

* Why was node-sass required? Odd

* Format webpack rejection error

* Re-enable unknown package test

* Format file not found error and catch module scope plugin error

* Re-disable case sensitive paths

* Intercept and format case sensitive path errors

* Test out of scope message formatting

* Run behavior on macOS

* Run behavior on Node 8 and 10, only Node 8 for macOS

* Add some debugging

* Update matcher

* Only check stderr

* Remove old snapshot

* More debug

* Remove debug

* Add new debug

* Disable test on linux

* Add comment for future

packages/react-dev-utils/eslintFormatter.js

@@ -42,6 +42,9 @@ function formatter(results) {
       }
 
       let line = message.line || 0;
+      if (message.column) {
+        line += ':' + message.column;
+      }
       let position = chalk.bold('Line ' + line + ':');
       return [
         '',

packages/react-dev-utils/formatWebpackMessages.js

@@ -7,15 +7,8 @@
 
 'use strict';
 
-// WARNING: this code is untranspiled and is used in browser too.
-// Please make sure any changes are in ES5 or contribute a Babel compile step.
-
-// Some custom utilities to prettify Webpack output.
-// This is quite hacky and hopefully won't be needed when Webpack fixes this.
-// https://github.com/webpack/webpack/issues/2878
-
-var chalk = require('chalk');
-var friendlySyntaxErrorLabel = 'Syntax error:';
+const chalk = require('chalk');
+const friendlySyntaxErrorLabel = 'Syntax error:';
 
 function isLikelyASyntaxError(message) {
   return message.indexOf(friendlySyntaxErrorLabel) !== -1;
@@ -24,159 +17,108 @@ function isLikelyASyntaxError(message) {
 // Cleans up webpack error messages.
 // eslint-disable-next-line no-unused-vars
 function formatMessage(message, isError) {
-  var lines = message.split('\n');
+  let lines = message.split('\n');
 
-  // Strip `WorkerError` header off message before parsing
-  // https://github.com/webpack-contrib/thread-loader/blob/6fb5daff313c4839196cf533bdcdf14815a386d2/src/WorkerError.js
-  lines = lines.filter(function(message) {
-    return message.indexOf('Thread Loader (Worker') === -1;
-  });
-
-  // Add empty line for errors from third-party webpack plugins
-  if (lines.length < 2) {
-    lines[1] = '';
-  }
+  // Strip Webpack-added headers off errors/warnings
+  // https://github.com/webpack/webpack/blob/master/lib/ModuleError.js
+  lines = lines.filter(line => !/Module [A-z ]+\(from/.test(line));
 
-  // Strip `ModuleWarning` head off message before parsing (because of ESLint)
-  // https://github.com/webpack/webpack/blob/c77030573de96b8293c69dd396492f8e2d46561e/lib/ModuleWarning.js
-  var moduleWarningPrefix = 'Module Warning: ';
-  if (lines[1].indexOf(moduleWarningPrefix) === 0) {
-    lines[1] = lines[1].slice(moduleWarningPrefix.length);
-  } else if (lines[1].match(/Module Warning \(from.*?\):/)) {
-    lines.splice(1, 1);
-  }
-
-  // Strip `ModuleError` header off message before parsing
-  // https://github.com/webpack/webpack/blob/c77030573de96b8293c69dd396492f8e2d46561e/lib/ModuleError.js
-  var moduleErrorPrefix = 'Module Error: ';
-  if (lines[1].indexOf(moduleErrorPrefix) === 0) {
-    lines[1] = lines[1].slice(moduleErrorPrefix.length);
-  } else if (lines[1].match(/Module Error \(from.*?\):/)) {
-    lines.splice(1, 1);
-  }
+  // Transform parsing error into syntax error
+  // TODO: move this to our ESLint formatter?
+  lines = lines.map(line => {
+    const parsingError = /Line (\d+):(?:(\d+):)?\s*Parsing error: (.+)$/.exec(
+      line
+    );
+    if (!parsingError) {
+      return line;
+    }
+    const [, errorLine, errorColumn, errorMessage] = parsingError;
+    return `${friendlySyntaxErrorLabel} ${errorMessage} (${errorLine}:${errorColumn})`;
+  });
 
-  // Simplify `ModuleBuildError` before parsing (these may be nested so we use a while loop)
-  // https://github.com/webpack/webpack/blob/c77030573de96b8293c69dd396492f8e2d46561e/lib/ModuleBuildError.js
-  while (
-    lines.length > 2 &&
-    lines[1].match(/Module build failed \(from.*?\):/)
-  ) {
-    lines.splice(1, 1);
-    lines[1] = 'Module build failed: ' + lines[1];
-  }
+  message = lines.join('\n');
+  // Smoosh syntax errors (commonly found in CSS)
+  message = message.replace(
+    /SyntaxError\s+\((\d+):(\d+)\)\s*(.+?)\n/g,
+    `${friendlySyntaxErrorLabel} $3 ($1:$2)\n`
+  );
+  // Remove columns from ESLint formatter output (we added these for more
+  // accurate syntax errors)
+  message = message.replace(/Line (\d+):\d+:/g, 'Line $1:');
+  // Clean up export errors
+  message = message.replace(
+    /^.*export '(.+?)' was not found in '(.+?)'.*$/gm,
+    `Attempted import error: '$1' is not exported from '$2'.`
+  );
+  message = message.replace(
+    /^.*export 'default' \(imported as '(.+?)'\) was not found in '(.+?)'.*$/gm,
+    `Attempted import error: '$2' does not contain a default export (imported as '$1').`
+  );
+  message = message.replace(
+    /^.*export '(.+?)' \(imported as '(.+?)'\) was not found in '(.+?)'.*$/gm,
+    `Attempted import error: '$1' is not exported from '$3' (imported as '$2').`
+  );
+  lines = message.split('\n');
 
-  if (lines.length > 2 && lines[1] === '') {
-    // Remove extra newline.
+  // Remove leading newline
+  if (lines.length > 2 && lines[1].trim() === '') {
     lines.splice(1, 1);
   }
-
-  // Remove webpack-specific loader notation from filename.
-  // Before:
-  // ./~/css-loader!./~/postcss-loader!./src/App.css
-  // After:
-  // ./src/App.css
-  if (lines[0].lastIndexOf('!') !== -1) {
-    lines[0] = lines[0].substr(lines[0].lastIndexOf('!') + 1);
-  }
-
-  lines = lines.filter(function(line) {
-    // Webpack adds a list of entry points to warning messages:
-    //  @ ./src/index.js
-    //  @ multi react-scripts/~/react-dev-utils/webpackHotDevClient.js ...
-    // It is misleading (and unrelated to the warnings) so we clean it up.
-    // It is only useful for syntax errors but we have beautiful frames for them.
-    return line.indexOf(' @ ') !== 0;
-  });
-
-  // line #0 is filename
-  // line #1 is the main error message
-  if (!lines[0] || !lines[1]) {
-    return lines.join('\n');
-  }
+  // Clean up file name
+  lines[0] = lines[0].replace(/^(.*) \d+:\d+-\d+$/, '$1');
 
   // Cleans up verbose "module not found" messages for files and packages.
-  if (lines[1].indexOf('Module not found: ') === 0) {
+  if (lines[1] && lines[1].indexOf('Module not found: ') === 0) {
     lines = [
       lines[0],
-      // Clean up message because "Module not found: " is descriptive enough.
       lines[1]
-        .replace("Cannot resolve 'file' or 'directory' ", '')
-        .replace('Cannot resolve module ', '')
         .replace('Error: ', '')
-        .replace('[CaseSensitivePathsPlugin] ', ''),
+        .replace('Module not found: Cannot find file:', 'Cannot find file:'),
     ];
   }
 
-  if (lines[1].match(/Cannot find module.+node-sass/)) {
-    lines[1] =
-      'To import Sass files in this project, you need to install node-sass.\n';
+  // Add helpful message for users trying to use Sass for the first time
+  if (lines[1] && lines[1].match(/Cannot find module.+node-sass/)) {
+    lines[1] = 'To import Sass files, you first need to install node-sass.\n';
     lines[1] +=
-      'Please run `npm i node-sass --save` or `yarn add node-sass` inside your workspace.';
-  }
-
-  // Cleans up syntax error messages.
-  if (lines[1].indexOf('Module build failed: ') === 0) {
-    lines[1] = lines[1].replace(
-      'Module build failed: Syntax Error ',
-      friendlySyntaxErrorLabel
-    );
-    lines[1] = lines[1].replace(
-      /Module build failed: .*?: /,
-      friendlySyntaxErrorLabel + ' '
-    );
-    lines[1] = lines[1].trim();
-
-    if (lines[1] === friendlySyntaxErrorLabel && lines[2] === '') {
-      lines.splice(2, 1);
-      if (lines.length > 2) {
-        lines[1] += ' ' + lines[2];
-        lines.splice(2, 1);
-      }
-    }
-  }
-
-  // Clean up export errors.
-  // TODO: we should really send a PR to Webpack for this.
-  var exportError = /\s*(.*?)\s*(?:")?export '(.+?)' was not found in '(.+?)'/;
-  if (lines[1].match(exportError)) {
-    lines[1] = lines[1].replace(
-      exportError,
-      "$1  '$3' does not contain an export named '$2'."
-    );
+      'Run `npm install node-sass` or `yarn add node-sass` inside your workspace.';
   }
 
   lines[0] = chalk.inverse(lines[0]);
 
-  // Reassemble the message.
   message = lines.join('\n');
   // Internal stacks are generally useless so we strip them... with the
   // exception of stacks containing `webpack:` because they're normally
-  // from user code generated by WebPack. For more information see
+  // from user code generated by Webpack. For more information see
   // https://github.com/facebook/create-react-app/pull/1050
   message = message.replace(
     /^\s*at\s((?!webpack:).)*:\d+:\d+[\s)]*(\n|$)/gm,
     ''
   ); // at ... ...:x:y
   message = message.replace(/^\s*at\s<anonymous>(\n|$)/gm, ''); // at <anonymous>
+  lines = message.split('\n');
 
+  // Remove duplicated newlines
+  lines = lines.filter(
+    (line, index, arr) =>
+      index === 0 || line.trim() !== '' || line.trim() !== arr[index - 1].trim()
+  );
+
+  // Reassemble the message
+  message = lines.join('\n');
   return message.trim();
 }
 
 function formatWebpackMessages(json) {
-  var formattedErrors = json.errors.map(function(message) {
+  const formattedErrors = json.errors.map(function(message) {
     return formatMessage(message, true);
   });
-  var formattedWarnings = json.warnings.map(function(message) {
+  const formattedWarnings = json.warnings.map(function(message) {
     return formatMessage(message, false);
   });
-  var result = {
-    errors: formattedErrors,
-    warnings: formattedWarnings,
-  };
+  const result = { errors: formattedErrors, warnings: formattedWarnings };
   if (result.errors.some(isLikelyASyntaxError)) {
     // If there are any syntax errors, show just them.
-    // This prevents a confusing ESLint parsing error
-    // preceding a much more useful Babel syntax error.
     result.errors = result.errors.filter(isLikelyASyntaxError);
   }
   return result;

packages/react-dev-utils/package.json

@@ -29,6 +29,7 @@
     "InterpolateHtmlPlugin.js",
     "launchEditor.js",
     "launchEditorEndpoint.js",
+    "ModuleNotFoundPlugin.js",
     "ModuleScopePlugin.js",
     "noopServiceWorkerMiddleware.js",
     "openBrowser.js",
@@ -48,6 +49,7 @@
     "detect-port-alt": "1.1.6",
     "escape-string-regexp": "1.0.5",
     "filesize": "3.6.1",
+    "find-up": "3.0.0",
     "global-modules": "1.0.0",
     "gzip-size": "5.0.0",
     "inquirer": "6.2.0",

packages/react-scripts/config/webpack.config.dev.js

@@ -20,6 +20,7 @@ const getClientEnvironment = require('./env');
 const paths = require('./paths');
 const ManifestPlugin = require('webpack-manifest-plugin');
 const getCacheIdentifier = require('react-dev-utils/getCacheIdentifier');
+const ModuleNotFoundPlugin = require('react-dev-utils/ModuleNotFoundPlugin');
 
 // Webpack uses `publicPath` to determine where the app is being served from.
 // In development, we always serve from the root. This makes config easier.
@@ -372,6 +373,9 @@ module.exports = {
     // <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico">
     // In development, this will be an empty string.
     new InterpolateHtmlPlugin(HtmlWebpackPlugin, env.raw),
+    // This gives some necessary context to module not found errors, such as
+    // the requesting resource.
+    new ModuleNotFoundPlugin(paths.appPath),
     // Makes some environment variables available to the JS code, for example:
     // if (process.env.NODE_ENV === 'development') { ... }. See `./env.js`.
     new webpack.DefinePlugin(env.stringified),

packages/react-scripts/config/webpack.config.prod.js

@@ -24,6 +24,7 @@ const getCSSModuleLocalIdent = require('react-dev-utils/getCSSModuleLocalIdent')
 const paths = require('./paths');
 const getClientEnvironment = require('./env');
 const getCacheIdentifier = require('react-dev-utils/getCacheIdentifier');
+const ModuleNotFoundPlugin = require('react-dev-utils/ModuleNotFoundPlugin');
 
 // Webpack uses `publicPath` to determine where the app is being served from.
 // It requires a trailing slash, or the file assets will get an incorrect path.
@@ -459,6 +460,9 @@ module.exports = {
     // In production, it will be an empty string unless you specify "homepage"
     // in `package.json`, in which case it will be the pathname of that URL.
     new InterpolateHtmlPlugin(HtmlWebpackPlugin, env.raw),
+    // This gives some necessary context to module not found errors, such as
+    // the requesting resource.
+    new ModuleNotFoundPlugin(paths.appPath),
     // Makes some environment variables available to the JS code, for example:
     // if (process.env.NODE_ENV === 'production') { ... }. See `./env.js`.
     // It is absolutely essential that NODE_ENV was set to production here.

packages/react-scripts/scripts/build.js

@@ -141,12 +141,20 @@ function build(previousFileSizes) {
   let compiler = webpack(config);
   return new Promise((resolve, reject) => {
     compiler.run((err, stats) => {
+      let messages;
       if (err) {
-        return reject(err);
+        if (!err.message) {
+          return reject(err);
+        }
+        messages = formatWebpackMessages({
+          errors: [err.message],
+          warnings: [],
+        });
+      } else {
+        messages = formatWebpackMessages(
+          stats.toJson({ all: false, warnings: true, errors: true })
+        );
       }
-      const messages = formatWebpackMessages(
-        stats.toJson({ all: false, warnings: true, errors: true })
-      );
       if (messages.errors.length) {
         // Only keep the first error. Others are often indicative
         // of the same problem, but confuse the reader with noise.

tasks/e2e-behavior.sh

@@ -96,10 +96,10 @@ git clean -df
 # ******************************************************************************
 
 # Smoke tests
-./node_modules/.bin/jest --config fixtures/smoke/jest.config.js
+CI=true ./node_modules/.bin/jest --config fixtures/smoke/jest.config.js
 
 # Output tests
-./node_modules/.bin/jest --config fixtures/output/jest.config.js
+CI=true ./node_modules/.bin/jest --config fixtures/output/jest.config.js
 
 # Cleanup
 cleanup