fix(@angular/cli): revert package.json changes if installation tasks fail during update

packages/angular/cli/src/commands/update/cli.ts

@@ -541,6 +541,14 @@ export default class UpdateCommandModule extends CommandModule<UpdateCommandArgs
       return 1;
     }
 
+    const packageJsonPath = path.join(this.context.root, 'package.json');
+    let originalPackageJsonContent: string | undefined;
+    try {
+      originalPackageJsonContent = await fs.readFile(packageJsonPath, 'utf8');
+    } catch {
+      // Ignore backup errors.
+    }
+
     try {
       await applyUpdatePlan(this.context.root, plan, logger);
     } catch (error) {
@@ -559,6 +567,11 @@ export default class UpdateCommandModule extends CommandModule<UpdateCommandArgs
     const tasks = new Listr([
       {
         title: 'Cleaning node modules directory',
+        skip() {
+          return packageManager.name !== 'npm'
+            ? 'Cleaning not required for this package manager.'
+            : false;
+        },
         async task(_, task) {
           try {
             await fs.rm(path.join(commandRoot, 'node_modules'), {
@@ -596,6 +609,16 @@ export default class UpdateCommandModule extends CommandModule<UpdateCommandArgs
         Module._pathCache = Object.create(null);
       }
     } catch (e) {
+      if (originalPackageJsonContent !== undefined) {
+        try {
+          await fs.writeFile(packageJsonPath, originalPackageJsonContent, 'utf8');
+          logger.info('Restored package.json to its original state.');
+        } catch (restoreError) {
+          assertIsError(restoreError);
+          logger.error(`Failed to restore package.json: ${restoreError.message}`);
+        }
+      }
+
       if (e instanceof CommandError) {
         return 1;
       }