Autocomplete nested objects bug fix

src/autocomplete/ResourceSectionCompletionProvider.ts

@@ -55,7 +55,8 @@ export class ResourceSectionCompletionProvider implements CompletionProvider {
                 ?.getCompletions(context, params) as CompletionItem[];
         } else if (
             context.entitySection === 'Properties' ||
-            ResourceAttributesSet.has(context.entitySection as string)
+            ResourceAttributesSet.has(context.entitySection as string) ||
+            (context.matchPathWithLogicalId(TopLevelSection.Resources, 'Properties') && context.propertyPath.length > 3)
         ) {
             const schemaPropertyCompletions = this.resourceProviders
                 .get(ResourceCompletionType.Property)

tst/e2e/autocomplete/Autocomplete.test.ts

@@ -1451,6 +1451,47 @@ O`,
             };
             template.executeScenario(scenario);
         });
+
+        it('test nested object property completion', () => {
+            const template = new TemplateBuilder(DocumentType.YAML);
+            const scenario: TemplateScenario = {
+                name: 'Nested object property completion',
+                steps: [
+                    {
+                        action: 'type',
+                        content: `AWSTemplateFormatVersion: '2010-09-09'
+Resources:
+  MyBucket:
+    Type: AWS::S3::Bucket
+    Properties:
+      NotificationConfiguration:
+        `,
+                        position: { line: 0, character: 0 },
+                        description: 'Test autocomplete in nested object within Properties',
+                        verification: {
+                            position: { line: 6, character: 8 },
+                            expectation: CompletionExpectationBuilder.create()
+                                .expectContainsItems([
+                                    'TopicConfigurations',
+                                    'QueueConfigurations',
+                                    'LambdaConfigurations',
+                                    'EventBridgeConfiguration',
+                                ])
+                                .build(),
+                        },
+                    },
+                    {
+                        action: 'type',
+                        content: `TopicConfigurations:
+          - Topic: arn:aws:sns:us-east-1:123456789012:my-topic
+            Event: s3:ObjectCreated:*`,
+                        position: { line: 6, character: 8 },
+                        description: 'Complete the nested object structure',
+                    },
+                ],
+            };
+            template.executeScenario(scenario);
+        });
     });
 
     describe('JSON', () => {
@@ -1479,5 +1520,43 @@ O`,
             };
             template.executeScenario(scenario);
         });
+
+        it('test nested object property completion', () => {
+            const template = new TemplateBuilder(DocumentType.JSON, '');
+            const scenario: TemplateScenario = {
+                name: 'Nested object property completion',
+                steps: [
+                    {
+                        action: 'type',
+                        position: { line: 0, character: 0 },
+                        content: `{
+  "AWSTemplateFormatVersion": "2010-09-09",
+  "Resources": {
+    "MyBucket": {
+      "Type": "AWS::S3::Bucket",
+      "Properties": {
+        "NotificationConfiguration": {
+          ""
+        }
+      }
+    }
+  }
+}`,
+                        verification: {
+                            position: { line: 7, character: 11 },
+                            expectation: CompletionExpectationBuilder.create()
+                                .expectContainsItems([
+                                    'TopicConfigurations',
+                                    'QueueConfigurations',
+                                    'LambdaConfigurations',
+                                    'EventBridgeConfiguration',
+                                ])
+                                .build(),
+                        },
+                    },
+                ],
+            };
+            template.executeScenario(scenario);
+        });
     });
 });

tst/unit/autocomplete/ResourceSectionCompletionProvider.test.ts

@@ -221,6 +221,37 @@ describe('ResourceSectionCompletionProvider', () => {
         spy.mockRestore();
     });
 
+    test('should delegate to property provider when in nested object within Properties (matchPathWithLogicalIds)', async () => {
+        const mockContext = createResourceContext('MyBucket', {
+            text: 'Topic',
+            propertyPath: ['Resources', 'MyBucket', 'Properties', 'NotificationConfiguration', 'Topic'],
+            data: {
+                Type: 'AWS::S3::Bucket',
+                Properties: {
+                    NotificationConfiguration: {},
+                },
+            },
+        });
+
+        const mockSchemas = createMockResourceSchemas();
+        setupMockSchemas(mockSchemas);
+
+        const propertyProvider = resourceProviders.get('Property' as any)!;
+        const mockCompletions = [
+            { label: 'TopicConfigurations', kind: CompletionItemKind.Property },
+            { label: 'QueueConfigurations', kind: CompletionItemKind.Property },
+            { label: 'LambdaConfigurations', kind: CompletionItemKind.Property },
+            { label: 'EventBridgeConfiguration', kind: CompletionItemKind.Property },
+        ];
+        const spy = vi.spyOn(propertyProvider, 'getCompletions').mockReturnValue(mockCompletions);
+
+        const result = await provider.getCompletions(mockContext, mockParams);
+
+        expect(spy).toHaveBeenCalledWith(mockContext, mockParams);
+        expect(result).toEqual(mockCompletions);
+        spy.mockRestore();
+    });
+
     test('should return empty array when no provider matches', async () => {
         const mockContext = createResourceContext('MyResource', {
             text: '',