From 7f7f09a8a758686e65518ea95f9cf085f4a7a32c Mon Sep 17 00:00:00 2001
From: Calvin Combs <comcalvi@amazon.com>
Date: Thu, 17 Aug 2023 13:34:40 -0700
Subject: [PATCH 1/4] tmp

---
 packages/aws-cdk/lib/cdk-toolkit.ts | 2 +-
 packages/aws-cdk/test/diff.test.ts  | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/aws-cdk/lib/cdk-toolkit.ts b/packages/aws-cdk/lib/cdk-toolkit.ts
index 1117271325e69..2a716c6096346 100644
--- a/packages/aws-cdk/lib/cdk-toolkit.ts
+++ b/packages/aws-cdk/lib/cdk-toolkit.ts
@@ -143,7 +143,7 @@ export class CdkToolkit {
         const currentTemplate = await this.props.deployments.readCurrentTemplateWithNestedStacks(stack, options.compareAgainstProcessedTemplate);
         diffs += options.securityOnly
           ? numberFromBool(printSecurityDiff(currentTemplate, stack, RequireApproval.Broadening))
-          : printStackDiff(currentTemplate, stack, strict, contextLines, quiet, stream);
+          : printStackDiff(currentTemplate, stack, strict, contextLines, quiet, stream) > 0 ? 1 : 0;
       }
     }
 
diff --git a/packages/aws-cdk/test/diff.test.ts b/packages/aws-cdk/test/diff.test.ts
index 789c80c9a1e06..2779ab1feb37d 100644
--- a/packages/aws-cdk/test/diff.test.ts
+++ b/packages/aws-cdk/test/diff.test.ts
@@ -85,6 +85,8 @@ describe('non-nested stacks', () => {
     expect(exitCode).toBe(0);
   });
 
+  test('diff reports correct number of stack diffs')
+
   test('exits with 1 with diffs and fail set to true', async () => {
     // GIVEN
     const buffer = new StringWritable();

From 3a04dfd59e6a3680daaa23f0042ce74d9097ba28 Mon Sep 17 00:00:00 2001
From: Calvin Combs <comcalvi@amazon.com>
Date: Fri, 18 Aug 2023 09:42:56 -0700
Subject: [PATCH 2/4] testing + correct nested stack counting

---
 packages/aws-cdk/lib/api/deployments.ts       |  10 +-
 .../aws-cdk/lib/api/nested-stack-helpers.ts   |  28 +++++
 packages/aws-cdk/lib/cdk-toolkit.ts           |  16 ++-
 .../api/cloudformation-deployments.test.ts    |  16 ++-
 packages/aws-cdk/test/diff.test.ts            | 103 +++++++++++++-----
 5 files changed, 134 insertions(+), 39 deletions(-)

diff --git a/packages/aws-cdk/lib/api/deployments.ts b/packages/aws-cdk/lib/api/deployments.ts
index a375bf25c4f65..cab9eb922a66d 100644
--- a/packages/aws-cdk/lib/api/deployments.ts
+++ b/packages/aws-cdk/lib/api/deployments.ts
@@ -6,7 +6,7 @@ import { ISDK } from './aws-auth/sdk';
 import { CredentialsOptions, SdkForEnvironment, SdkProvider } from './aws-auth/sdk-provider';
 import { deployStack, DeployStackResult, destroyStack, makeBodyParameterAndUpload, DeploymentMethod } from './deploy-stack';
 import { HotswapMode } from './hotswap/common';
-import { loadCurrentTemplateWithNestedStacks, loadCurrentTemplate } from './nested-stack-helpers';
+import { loadCurrentTemplateWithNestedStacks, loadCurrentTemplate, flattenNestedStackNames, TemplateWithNestedStackCount } from './nested-stack-helpers';
 import { ToolkitInfo } from './toolkit-info';
 import { CloudFormationStack, Template, ResourcesToImport, ResourceIdentifierSummaries } from './util/cloudformation';
 import { StackActivityProgress } from './util/cloudformation/stack-activity-monitor';
@@ -300,9 +300,13 @@ export class Deployments {
   public async readCurrentTemplateWithNestedStacks(
     rootStackArtifact: cxapi.CloudFormationStackArtifact,
     retrieveProcessedTemplate: boolean = false,
-  ): Promise<Template> {
+  ): Promise<TemplateWithNestedStackCount> {
     const sdk = (await this.prepareSdkWithLookupOrDeployRole(rootStackArtifact)).stackSdk;
-    return (await loadCurrentTemplateWithNestedStacks(rootStackArtifact, sdk, retrieveProcessedTemplate)).deployedTemplate;
+    const templateWithNestedStacks = await loadCurrentTemplateWithNestedStacks(rootStackArtifact, sdk, retrieveProcessedTemplate);
+    return {
+      deployedTemplate: templateWithNestedStacks.deployedTemplate,
+      nestedStackCount: flattenNestedStackNames(templateWithNestedStacks.nestedStackNames).length,
+    };
   }
 
   public async readCurrentTemplate(stackArtifact: cxapi.CloudFormationStackArtifact): Promise<Template> {
diff --git a/packages/aws-cdk/lib/api/nested-stack-helpers.ts b/packages/aws-cdk/lib/api/nested-stack-helpers.ts
index 6703bf48cb4a5..8b0050e3f673e 100644
--- a/packages/aws-cdk/lib/api/nested-stack-helpers.ts
+++ b/packages/aws-cdk/lib/api/nested-stack-helpers.ts
@@ -15,6 +15,11 @@ export interface NestedStackNames {
   readonly nestedChildStackNames: { [logicalId: string]: NestedStackNames };
 }
 
+export interface TemplateWithNestedStackCount {
+  readonly deployedTemplate: Template;
+  readonly nestedStackCount: number;
+}
+
 /**
  * Reads the currently deployed template from CloudFormation and adds a
  * property, `NestedTemplate`, to any nested stacks that appear in either
@@ -40,6 +45,19 @@ export async function loadCurrentTemplateWithNestedStacks(
   };
 }
 
+export function flattenNestedStackNames(nestedStackNames: { [nestedStackLogicalId: string]: NestedStackNames }): string[] {
+  const nameList = [];
+  for (const key of Object.keys(nestedStackNames)) {
+    nameList.push(key);
+
+    if (Object.keys(nestedStackNames[key].nestedChildStackNames).length !== 0) {
+      countNestedStacksHelper(nestedStackNames[key].nestedChildStackNames, nameList);
+    }
+  }
+
+  return nameList;
+}
+
 /**
  * Returns the currently deployed template from CloudFormation that corresponds to `stackArtifact`.
  */
@@ -135,6 +153,16 @@ function isCdkManagedNestedStack(stackResource: any): stackResource is NestedSta
   return stackResource.Type === 'AWS::CloudFormation::Stack' && stackResource.Metadata && stackResource.Metadata['aws:asset:path'];
 }
 
+function countNestedStacksHelper(nestedStackNames: { [logicalId: string]: NestedStackNames }, nameList: string[]) {
+  for (const key of Object.keys(nestedStackNames)) {
+    nameList.push(key);
+
+    if (Object.keys(nestedStackNames[key].nestedChildStackNames).length !== 0) {
+      countNestedStacksHelper(nestedStackNames[key].nestedChildStackNames, nameList);
+    }
+  }
+}
+
 interface StackTemplates {
   readonly generatedTemplate: any;
   readonly deployedTemplate: any;
diff --git a/packages/aws-cdk/lib/cdk-toolkit.ts b/packages/aws-cdk/lib/cdk-toolkit.ts
index 2a716c6096346..a34c3d78e9cd0 100644
--- a/packages/aws-cdk/lib/cdk-toolkit.ts
+++ b/packages/aws-cdk/lib/cdk-toolkit.ts
@@ -140,10 +140,18 @@ export class CdkToolkit {
           stream.write(format('Stack %s\n', chalk.bold(stack.displayName)));
         }
 
-        const currentTemplate = await this.props.deployments.readCurrentTemplateWithNestedStacks(stack, options.compareAgainstProcessedTemplate);
-        diffs += options.securityOnly
-          ? numberFromBool(printSecurityDiff(currentTemplate, stack, RequireApproval.Broadening))
-          : printStackDiff(currentTemplate, stack, strict, contextLines, quiet, stream) > 0 ? 1 : 0;
+        const templateWithNames = await this.props.deployments.readCurrentTemplateWithNestedStacks(
+          stack, options.compareAgainstProcessedTemplate,
+        );
+        const currentTemplate = templateWithNames.deployedTemplate;
+        const nestedStackCount = templateWithNames.nestedStackCount;
+
+        const stackCount =
+        options.securityOnly
+          ? (numberFromBool(printSecurityDiff(currentTemplate, stack, RequireApproval.Broadening)) > 0 ? 1 : 0)
+          : (printStackDiff(currentTemplate, stack, strict, contextLines, quiet, stream) > 0 ? 1 : 0);
+
+        diffs += stackCount + nestedStackCount;
       }
     }
 
diff --git a/packages/aws-cdk/test/api/cloudformation-deployments.test.ts b/packages/aws-cdk/test/api/cloudformation-deployments.test.ts
index 95a7a767c3f9a..fdb4b8a5eb0e5 100644
--- a/packages/aws-cdk/test/api/cloudformation-deployments.test.ts
+++ b/packages/aws-cdk/test/api/cloudformation-deployments.test.ts
@@ -246,9 +246,11 @@ test('readCurrentTemplateWithNestedStacks() can handle non-Resources in the temp
   );
 
   // WHEN
-  const deployedTemplate = await deployments.readCurrentTemplateWithNestedStacks(rootStack);
+  const nestedStackCount = (await deployments.readCurrentTemplateWithNestedStacks(rootStack)).nestedStackCount;
+  const deployedTemplate = (await deployments.readCurrentTemplateWithNestedStacks(rootStack)).deployedTemplate;
 
   // THEN
+  expect(nestedStackCount).toEqual(1);
   expect(deployedTemplate).toEqual({
     Resources: {
       NestedStack: {
@@ -451,9 +453,11 @@ test('readCurrentTemplateWithNestedStacks() with a 3-level nested + sibling stru
   );
 
   // WHEN
-  const deployedTemplate = await deployments.readCurrentTemplateWithNestedStacks(rootStack);
+  const nestedStackCount = (await deployments.readCurrentTemplateWithNestedStacks(rootStack)).nestedStackCount;
+  const deployedTemplate = (await deployments.readCurrentTemplateWithNestedStacks(rootStack)).deployedTemplate;
 
   // THEN
+  expect(nestedStackCount).toEqual(3);
   expect(deployedTemplate).toEqual({
     Resources: {
       NestedStack: {
@@ -608,9 +612,11 @@ test('readCurrentTemplateWithNestedStacks() on an undeployed parent stack with a
   });
 
   // WHEN
-  const deployedTemplate = await deployments.readCurrentTemplateWithNestedStacks(rootStack);
+  const nestedStackCount = (await deployments.readCurrentTemplateWithNestedStacks(rootStack)).nestedStackCount;
+  const deployedTemplate = (await deployments.readCurrentTemplateWithNestedStacks(rootStack)).deployedTemplate;
 
   // THEN
+  expect(nestedStackCount).toEqual(2);
   expect(deployedTemplate).toEqual({
     Resources: {
       NestedStack: {
@@ -781,9 +787,11 @@ test('readCurrentTemplateWithNestedStacks() succesfully ignores stacks without m
   ));
 
   // WHEN
-  const deployedTemplate = await deployments.readCurrentTemplateWithNestedStacks(rootStack);
+  const nestedStackCount = (await deployments.readCurrentTemplateWithNestedStacks(rootStack)).nestedStackCount;
+  const deployedTemplate = (await deployments.readCurrentTemplateWithNestedStacks(rootStack)).deployedTemplate;
 
   // THEN
+  expect(nestedStackCount).toEqual(1);
   expect(deployedTemplate).toEqual({
     Resources: {
       WithMetadata: {
diff --git a/packages/aws-cdk/test/diff.test.ts b/packages/aws-cdk/test/diff.test.ts
index 2779ab1feb37d..02ad58989a695 100644
--- a/packages/aws-cdk/test/diff.test.ts
+++ b/packages/aws-cdk/test/diff.test.ts
@@ -54,9 +54,15 @@ describe('non-nested stacks', () => {
     // Default implementations
     cloudFormation.readCurrentTemplateWithNestedStacks.mockImplementation((stackArtifact: CloudFormationStackArtifact) => {
       if (stackArtifact.stackName === 'D') {
-        return Promise.resolve({ resource: 'D' });
+        return Promise.resolve({
+          deployedTemplate: { resource: 'D' },
+          nestedStackCount: 0,
+        });
       }
-      return Promise.resolve({});
+      return Promise.resolve({
+        deployedTemplate: {},
+        nestedStackCount: 0,
+      });
     });
     cloudFormation.deployStack.mockImplementation((options) => Promise.resolve({
       noOp: true,
@@ -85,7 +91,42 @@ describe('non-nested stacks', () => {
     expect(exitCode).toBe(0);
   });
 
-  test('diff reports correct number of stack diffs')
+  test('diff number of stack diffs, not resource diffs', async () => {
+    // GIVEN
+    cloudExecutable = new MockCloudExecutable({
+      stacks: [{
+        stackName: 'A',
+        template: { resourceA: 'A', resourceB: 'B' },
+      },
+      {
+        stackName: 'B',
+        template: { resourceC: 'C' },
+      }],
+    });
+
+    toolkit = new CdkToolkit({
+      cloudExecutable,
+      deployments: cloudFormation,
+      configuration: cloudExecutable.configuration,
+      sdkProvider: cloudExecutable.sdkProvider,
+    });
+
+    const buffer = new StringWritable();
+
+    // WHEN
+    const exitCode = await toolkit.diff({
+      stackNames: ['A', 'B'],
+      stream: buffer,
+    });
+
+    // THEN
+    const plainTextOutput = buffer.data.replace(/\x1B\[[0-?]*[ -/]*[@-~]/g, '');
+    expect(plainTextOutput).toContain('Stack A');
+    expect(plainTextOutput).toContain('Stack B');
+
+    expect(buffer.data.trim()).toContain('✨  Number of stacks with differences: 2');
+    expect(exitCode).toBe(0);
+  });
 
   test('exits with 1 with diffs and fail set to true', async () => {
     // GIVEN
@@ -211,46 +252,52 @@ describe('nested stacks', () => {
           },
         };
         return Promise.resolve({
-          Resources: {
-            AdditionChild: {
-              Type: 'AWS::CloudFormation::Stack',
-              Resources: {
-                SomeResource: {
-                  Type: 'AWS::Something',
+          deployedTemplate: {
+            Resources: {
+              AdditionChild: {
+                Type: 'AWS::CloudFormation::Stack',
+                Resources: {
+                  SomeResource: {
+                    Type: 'AWS::Something',
+                  },
                 },
               },
-            },
-            DeletionChild: {
-              Type: 'AWS::CloudFormation::Stack',
-              Resources: {
-                SomeResource: {
-                  Type: 'AWS::Something',
-                  Properties: {
-                    Prop: 'value-to-be-removed',
+              DeletionChild: {
+                Type: 'AWS::CloudFormation::Stack',
+                Resources: {
+                  SomeResource: {
+                    Type: 'AWS::Something',
+                    Properties: {
+                      Prop: 'value-to-be-removed',
+                    },
                   },
                 },
               },
-            },
-            ChangedChild: {
-              Type: 'AWS::CloudFormation::Stack',
-              Resources: {
-                SomeResource: {
-                  Type: 'AWS::Something',
-                  Properties: {
-                    Prop: 'old-value',
+              ChangedChild: {
+                Type: 'AWS::CloudFormation::Stack',
+                Resources: {
+                  SomeResource: {
+                    Type: 'AWS::Something',
+                    Properties: {
+                      Prop: 'old-value',
+                    },
                   },
                 },
               },
             },
           },
+          nestedStackCount: 3,
         });
       }
-      return Promise.resolve({});
+      return Promise.resolve({
+        deployedTemplate: {},
+        nestedStackCount: 0,
+      });
     });
   });
 
   test('diff can diff nested stacks', async () => {
-    // GIVEN
+  // GIVEN
     const buffer = new StringWritable();
 
     // WHEN
@@ -281,7 +328,7 @@ Resources
                  └─ [+] new-value
 
 
-✨  Number of stacks with differences: 3`);
+✨  Number of stacks with differences: 4`);
 
     expect(exitCode).toBe(0);
   });

From 63aa27f87e3546b5b092020437d04946cd496faa Mon Sep 17 00:00:00 2001
From: Calvin Combs <comcalvi@amazon.com>
Date: Fri, 18 Aug 2023 10:01:56 -0700
Subject: [PATCH 3/4] whitespace

---
 packages/aws-cdk/test/diff.test.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/aws-cdk/test/diff.test.ts b/packages/aws-cdk/test/diff.test.ts
index 02ad58989a695..47a6f5f44515c 100644
--- a/packages/aws-cdk/test/diff.test.ts
+++ b/packages/aws-cdk/test/diff.test.ts
@@ -204,7 +204,7 @@ describe('nested stacks', () => {
     cloudExecutable = new MockCloudExecutable({
       stacks: [{
         stackName: 'Parent',
-        template: { },
+        template: {},
       }],
     });
 
@@ -297,7 +297,7 @@ describe('nested stacks', () => {
   });
 
   test('diff can diff nested stacks', async () => {
-  // GIVEN
+    // GIVEN
     const buffer = new StringWritable();
 
     // WHEN

From 936e277edfae65246769d7c5bb07ffa8cf9f9449 Mon Sep 17 00:00:00 2001
From: Calvin Combs <comcalvi@amazon.com>
Date: Mon, 21 Aug 2023 10:11:55 -0700
Subject: [PATCH 4/4] rename helper method

---
 packages/aws-cdk/lib/api/nested-stack-helpers.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/aws-cdk/lib/api/nested-stack-helpers.ts b/packages/aws-cdk/lib/api/nested-stack-helpers.ts
index 8b0050e3f673e..acbbb1e2a9245 100644
--- a/packages/aws-cdk/lib/api/nested-stack-helpers.ts
+++ b/packages/aws-cdk/lib/api/nested-stack-helpers.ts
@@ -51,7 +51,7 @@ export function flattenNestedStackNames(nestedStackNames: { [nestedStackLogicalI
     nameList.push(key);
 
     if (Object.keys(nestedStackNames[key].nestedChildStackNames).length !== 0) {
-      countNestedStacksHelper(nestedStackNames[key].nestedChildStackNames, nameList);
+      flattenNestedStacksHelper(nestedStackNames[key].nestedChildStackNames, nameList);
     }
   }
 
@@ -153,12 +153,12 @@ function isCdkManagedNestedStack(stackResource: any): stackResource is NestedSta
   return stackResource.Type === 'AWS::CloudFormation::Stack' && stackResource.Metadata && stackResource.Metadata['aws:asset:path'];
 }
 
-function countNestedStacksHelper(nestedStackNames: { [logicalId: string]: NestedStackNames }, nameList: string[]) {
+function flattenNestedStacksHelper(nestedStackNames: { [logicalId: string]: NestedStackNames }, nameList: string[]) {
   for (const key of Object.keys(nestedStackNames)) {
     nameList.push(key);
 
     if (Object.keys(nestedStackNames[key].nestedChildStackNames).length !== 0) {
-      countNestedStacksHelper(nestedStackNames[key].nestedChildStackNames, nameList);
+      flattenNestedStacksHelper(nestedStackNames[key].nestedChildStackNames, nameList);
     }
   }
 }