Try to fix CI (facebook#3806)

* Try to fix CI

* Bump Jest elsewhere

* Bump Babel elsewhere

* Fix CI on Windows by writing .cmd file back

Author: gaearon

package.json

@@ -26,7 +26,7 @@
     "autoprefixer": "7.2.5",
     "babel-core": "7.0.0-bridge.0",
     "babel-eslint": "8.2.1",
-    "babel-jest": "22.0.6",
+    "babel-jest": "22.1.0",
     "babel-loader": "8.0.0-beta.0",
     "babel-preset-react-app": "^3.1.1",
     "case-sensitive-paths-webpack-plugin": "2.1.1",
@@ -45,7 +45,7 @@
     "file-loader": "1.1.6",
     "fs-extra": "5.0.0",
     "html-webpack-plugin": "2.30.1",
-    "jest": "22.0.6",
+    "jest": "22.1.1",
     "object-assign": "4.1.1",
     "postcss-flexbugs-fixes": "3.2.0",
     "postcss-loader": "2.0.10",

scripts/eject.js

@@ -237,21 +237,35 @@ inquirer
     }
 
     if (fs.existsSync(paths.yarnLockFile)) {
-      // TODO: this is disabled for three reasons.
-      //
-      // 1. It produces garbage warnings on Windows on some systems:
-      //    https://github.com/facebookincubator/create-react-app/issues/2030
-      //
-      // 2. For the above reason, it breaks Windows CI:
-      //    https://github.com/facebookincubator/create-react-app/issues/2624
-      //
-      // 3. It is wrong anyway: re-running yarn will respect the lockfile
-      //    rather than package.json we just updated. Instead we should have
-      //    updated the lockfile. So we might as well not do it while it's broken.
-      //    https://github.com/facebookincubator/create-react-app/issues/2627
-      //
-      // console.log(cyan('Running yarn...'));
-      // spawnSync('yarnpkg', [], { stdio: 'inherit' });
+      const windowsCmdFilePath = path.join(
+        appPath,
+        'node_modules',
+        '.bin',
+        'react-scripts.cmd'
+      );
+      let windowsCmdFileContent;
+      if (process.platform === 'win32') {
+        // https://github.com/facebookincubator/create-react-app/pull/3806#issuecomment-357781035
+        // Yarn is diligent about cleaning up after itself, but this causes the react-scripts.cmd file
+        // to be deleted while it is running. This trips Windows up after the eject completes.
+        // We'll read the batch file and later "write it back" to match npm behavior.
+        try {
+          windowsCmdFileContent = fs.readFileSync(windowsCmdFilePath);
+        } catch (err) {
+          // If this fails we're not worse off than if we didn't try to fix it.
+        }
+      }
+
+      console.log(cyan('Running yarn...'));
+      spawnSync('yarnpkg', ['--cwd', process.cwd()], { stdio: 'inherit' });
+
+      if (windowsCmdFileContent && !fs.existsSync(windowsCmdFilePath)) {
+        try {
+          fs.writeFileSync(windowsCmdFilePath, windowsCmdFileContent);
+        } catch (err) {
+          // If this fails we're not worse off than if we didn't try to fix it.
+        }
+      }
     } else {
       console.log(cyan('Running npm install...'));
       spawnSync('npm', ['install', '--loglevel', 'error'], {