[clint] Unblock Github Copilot by trying a shallow-clone workaround

Author: clintandrewhall

packages/eui/scripts/test-staged.js

@@ -1,6 +1,48 @@
 const { execSync } = require('child_process');
 
+const isShallowClone = () => {
+  try {
+    return execSync('git rev-parse --is-shallow-repository', { 
+      encoding: 'utf8' 
+    }).trim() === 'true';
+  } catch (e) {
+    return false;
+  }
+};
+
+const tryUnshallow = () => {
+  if (!isShallowClone()) return true;
+  
+  console.log('📦 Shallow clone detected, fetching full history...');
+  try {
+    execSync('git fetch --unshallow origin', { stdio: 'inherit' });
+    execSync('git fetch origin main:main', { stdio: 'inherit' });
+    console.log('✅ Successfully fetched full history');
+    return true;
+  } catch (e) {
+    console.warn('⚠️  Could not fetch full history');
+    return false;
+  }
+};
+
+const canUseChangedSince = () => {
+  try {
+    execSync('git merge-base HEAD main', { stdio: 'ignore' });
+    return true;
+  } catch (e) {
+    return false;
+  }
+};
+
+// Main logic: try to use --changedSince, fall back to all tests if needed
 // https://jestjs.io/docs/cli#--changedsince
-execSync(`yarn test-unit --changedSince main`, {
-  stdio: 'inherit',
-});
+if (tryUnshallow() || canUseChangedSince()) {
+  execSync(`yarn test-unit --changedSince main`, {
+    stdio: 'inherit',
+  });
+} else {
+  console.warn('⚠️  Running all tests (cannot determine changed files)');
+  execSync(`yarn test-unit`, {
+    stdio: 'inherit',
+  });
+}