First version of WatchPackageJsonPlugin. It takes care of recompiling…

… erroneous files when package.json is changed, because it might resolve the issue.

packages/react-dev-utils/WatchPackageJsonPlugin.js

@@ -0,0 +1,51 @@
+'use strict';
+
+// This Webpack plugin ensures that package.json is watched for changes and
+// that appropriate actions are triggered, e.g. an eslint-loader recheck.
+
+class WatchPackageJsonPlugin {
+  constructor(packageJsonPath) {
+    this.packageJsonPath = packageJsonPath;
+    this.erroneousFiles = [];
+  }
+
+  apply(compiler) {
+    compiler.plugin('compilation', compilation => {
+      const timestamp = compilation.fileTimestamps[this.packageJsonPath] || 0;
+
+      if (timestamp > this.previousTimestamp && this.erroneousFiles.length) {
+        this.erroneousFiles.forEach(filename => {
+          compilation.fileTimestamps[filename] = timestamp;
+        });
+      }
+    });
+
+    compiler.plugin('emit', (compilation, callback) => {
+      // Add package.json to the list of watched files. This needs to be done
+      // for every compilation run since the list is rebuilt every time.
+      compilation.fileDependencies.push(this.packageJsonPath);
+
+      this.previousTimestamp = compilation.fileTimestamps[
+        this.packageJsonPath
+      ] || 0;
+
+      // First we extract all files related to any occurred errors. Then
+      // we remove any request params that could have been added by a plugin,
+      // loader or the user.
+      this.erroneousFiles = compilation.errors
+        .reduce(
+          (acc, error) => {
+            acc.push.apply(acc, error.dependencies);
+
+            return acc;
+          },
+          []
+        )
+        .map(entry => entry.request.replace(/\?.*$/));
+
+      callback();
+    });
+  }
+}
+
+module.exports = WatchPackageJsonPlugin;

packages/react-dev-utils/package.json

@@ -23,6 +23,7 @@
     "openChrome.applescript",
     "prompt.js",
     "WatchMissingNodeModulesPlugin.js",
+    "WatchPackageJsonPlugin.js",
     "webpackHotDevClient.js"
   ],
   "dependencies": {

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

@@ -16,6 +16,7 @@ const HtmlWebpackPlugin = require('html-webpack-plugin');
 const CaseSensitivePathsPlugin = require('case-sensitive-paths-webpack-plugin');
 const InterpolateHtmlPlugin = require('react-dev-utils/InterpolateHtmlPlugin');
 const WatchMissingNodeModulesPlugin = require('react-dev-utils/WatchMissingNodeModulesPlugin');
+const WatchPackageJsonPlugin = require('react-dev-utils/WatchPackageJsonPlugin');
 const getClientEnvironment = require('./env');
 const paths = require('./paths');
 
@@ -244,6 +245,9 @@ module.exports = {
     // makes the discovery automatic so you don't have to restart.
     // See https://github.com/facebookincubator/create-react-app/issues/186
     new WatchMissingNodeModulesPlugin(paths.appNodeModules),
+    // This Webpack plugin ensures that package.json is watched for changes and
+    // that appropriate actions are triggered, e.g. an eslint-loader recheck.
+    new WatchPackageJsonPlugin(paths.appPackageJson),
   ],
   // Some libraries import Node modules but don't use them in the browser.
   // Tell Webpack to provide empty mocks for them so importing them works.