Ejecting should ensure you have clean git status

packages/react-scripts/scripts/eject.js

@@ -21,6 +21,7 @@ const path = require('path');
 const spawnSync = require('cross-spawn').sync;
 const chalk = require('chalk');
 const prompt = require('react-dev-utils/prompt');
+const execSync = require('child_process').execSync;
 const paths = require('../config/paths');
 const createJestConfig = require('./utils/createJestConfig');
 
@@ -36,6 +37,31 @@ prompt(
     process.exit(1);
   }
 
+  // Make sure there are no dirty git status
+  const git = fs.existsSync(path.join(process.cwd(), '.git'));
+
+  function statusSync() {
+    let stdout = execSync(`git status -s`).toString();
+    let status = { dirty: 0, untracked: 0 };
+    stdout.trim().split(/\r?\n/).forEach(file => {
+      if (file.substr(0, 2) === '??') status.untracked++;
+      else status.dirty++;
+    });
+    return status;
+  }
+
+  if (git) {
+    let status = statusSync();
+    if (status.dirty) {
+      console.error(
+        `Git repository has ${status.dirty} dirty ${status.dirty > 1 ? 'files' : 'file'}. ` +
+          'We cannot continue as you would lose all the changes in that file or directory. ' +
+          'Please push commit before and run this command again.'
+      );
+      process.exit(1);
+    }
+  }
+
   console.log('Ejecting...');
 
   const ownPath = paths.ownPath;