fix(cli): diff allow specifying changeSet via cdk.json

packages/@aws-cdk-testing/cli-integ/tests/cli-integ-tests/cli.integtest.ts

@@ -749,6 +749,27 @@ integTest('enableDiffNoFail', withDefaultFixture(async (fixture) => {
   type DiffParameters = { fail?: boolean; enableDiffNoFail: boolean };
 }));
 
+integTest('cdk diff should not show verbose messages by default', withDefaultFixture(async (fixture) => {
+  const diff = await fixture.cdk(['diff', fixture.fullStackName('test-1')], { verbose: false });
+  expect(diff).not.toContain('Hold on while we create a read-only change set');
+}));
+
+integTest('cdk diff should only show verbose messages in --verbose mode', withDefaultFixture(async (fixture) => {
+  const diff = await fixture.cdk(['diff', fixture.fullStackName('test-1')], { verbose: true });
+  expect(diff).toContain('Hold on while we create a read-only change set');
+}));
+
+integTest('cdk diff should allow configuring whether to use changesets via cdk.json', withDefaultFixture(async (fixture) => {
+  const cdkJson = JSON.parse(await fs.readFile(path.join(fixture.integTestDir, 'cdk.json'), 'utf8'));
+  cdkJson.diff = {
+    changeSet: false,
+  };
+  await fs.writeFile(path.join(fixture.integTestDir, 'cdk.json'), JSON.stringify(cdkJson));
+
+  const diff = await fixture.cdk(['diff', fixture.fullStackName('test-1')], { verbose: true });
+  expect(diff).not.toContain('Hold on while we create a read-only change set');
+}));
+
 integTest('cdk diff --fail on multiple stacks exits with error if any of the stacks contains a diff', withDefaultFixture(async (fixture) => {
   // GIVEN
   const diff1 = await fixture.cdk(['diff', fixture.fullStackName('test-1')]);

packages/aws-cdk/README.md

@@ -169,6 +169,16 @@ The `change-set` flag will make `diff` create a change set and extract resource
 The `--no-change-set` mode will consider any change to a property that requires replacement to be a resource replacement,
 even if the change is purely cosmetic (like replacing a resource reference with a hardcoded arn).
 
+The `change-set` option can be set in the `cdk.json` file.
+
+```json
+{
+  "diff": {
+    "changeSet": false
+  }
+}
+```
+
 ### `cdk deploy`
 
 Deploys a stack of your CDK app to its environment. During the deployment, the toolkit will output progress

packages/aws-cdk/lib/api/util/cloudformation.ts

@@ -341,7 +341,7 @@ async function uploadBodyParameterAndCreateChangeSet(options: PrepareChangeSetOp
     const exists = (await CloudFormationStack.lookup(cfn, options.stack.stackName, false)).exists;
 
     const executionRoleArn = preparedSdk.cloudFormationRoleArn;
-    options.stream.write('Hold on while we create a read-only change set to get a diff with accurate replacement information (use --no-change-set to use a less accurate but faster template-only diff)\n');
+    debug('Hold on while we create a read-only change set to get a diff with accurate replacement information (use --no-change-set to use a less accurate but faster template-only diff)');
 
     return await createChangeSet({
       cfn,

packages/aws-cdk/lib/cli.ts

@@ -514,7 +514,7 @@ export async function exec(args: string[], synthesizer?: Synthesizer): Promise<n
           stream: args.ci ? process.stdout : undefined,
           compareAgainstProcessedTemplate: args.processed,
           quiet: args.quiet,
-          changeSet: args['change-set'],
+          changeSet: configuration.settings.get(['diff', 'changeSet']) ?? args['change-set'],
         });
 
       case 'bootstrap':