fix(@schematics/angular): prevent crash in getDecoratorMetadata with undefined expressions

packages/schematics/angular/utility/ast-utils.ts

@@ -323,20 +323,21 @@ export function getDecoratorMetadata(
     .filter((node) => {
       return (
         node.kind == ts.SyntaxKind.Decorator &&
+        (node as ts.Decorator).expression &&
         (node as ts.Decorator).expression.kind == ts.SyntaxKind.CallExpression
       );
     })
     .map((node) => (node as ts.Decorator).expression as ts.CallExpression)
     .filter((expr) => {
-      if (expr.expression.kind == ts.SyntaxKind.Identifier) {
+      if (expr.expression && expr.expression.kind == ts.SyntaxKind.Identifier) {
         const id = expr.expression as ts.Identifier;
 
         return id.text == identifier && angularImports[id.text] === module;
       } else if (expr.expression.kind == ts.SyntaxKind.PropertyAccessExpression) {
         // This covers foo.NgModule when importing * as foo.
         const paExpr = expr.expression as ts.PropertyAccessExpression;
         // If the left expression is not an identifier, just give up at that point.
-        if (paExpr.expression.kind !== ts.SyntaxKind.Identifier) {
+        if (!paExpr.expression || paExpr.expression.kind !== ts.SyntaxKind.Identifier) {
           return false;
         }
 

packages/schematics/angular/utility/ast-utils_spec.ts

@@ -16,6 +16,7 @@ import {
   addRouteDeclarationToModule,
   addSymbolToNgModuleMetadata,
   findNodes,
+  getDecoratorMetadata,
   hasTopLevelIdentifier,
   insertAfterLastOccurrence,
   insertImport,
@@ -839,4 +840,53 @@ describe('ast utils', () => {
       expect(hasTopLevelIdentifier(source, 'FooInterface', '@foo/interfaces')).toBe(false);
     });
   });
+
+  describe('getDecoratorMetadata', () => {
+    const filePath = './src/app.module.ts';
+
+    it('should return decorator metadata for a valid NgModule', () => {
+      const fileContent = `
+        import { NgModule } from '@angular/core';
+
+        @NgModule({
+          declarations: [],
+          imports: []
+        })
+        export class AppModule { }
+      `;
+      const source = getTsSource(filePath, fileContent);
+      const nodes = getDecoratorMetadata(source, 'NgModule', '@angular/core');
+
+      expect(nodes.length).toBe(1);
+      expect(nodes[0].kind).toBe(ts.SyntaxKind.ObjectLiteralExpression);
+    });
+
+    it('should not crash when processing files without decorators', () => {
+      const fileContent = `
+        export const environment = {
+          production: false
+        };
+      `;
+      const source = getTsSource(filePath, fileContent);
+      const nodes = getDecoratorMetadata(source, 'NgModule', '@angular/core');
+
+      expect(nodes.length).toBe(0);
+    });
+
+    it('should handle namespace imports correctly', () => {
+      const fileContent = `
+        import * as ng from '@angular/core';
+
+        @ng.NgModule({
+          declarations: []
+        })
+        export class AppModule { }
+      `;
+      const source = getTsSource(filePath, fileContent);
+      const nodes = getDecoratorMetadata(source, 'NgModule', '@angular/core');
+
+      expect(nodes.length).toBe(1);
+      expect(nodes[0].kind).toBe(ts.SyntaxKind.ObjectLiteralExpression);
+    });
+  });
 });