Revert "fix(cli): always exit with 0 on cdk diff (#4650)" (#4708)

This change includes a breaking change in our stable APIs.
We will have to discuss this furthre in order to make a decision
to actually break.

This reverts commit 4f765b2.

packages/aws-cdk/bin/cdk.ts

@@ -67,7 +67,6 @@ async function parseCommandLineArguments() {
       .option('context-lines', { type: 'number', desc: 'Number of context lines to include in arbitrary JSON diff rendering', default: 3, requiresArg: true })
       .option('template', { type: 'string', desc: 'The path to the CloudFormation template to compare with', requiresArg: true })
       .option('strict', { type: 'boolean', desc: 'Do not filter out AWS::CDK::Metadata resources', default: false }))
-      .option('fail', { type: 'boolean', desc: 'Fail with exit code 1 in case of diff', default: false })
     .command('metadata [STACK]', 'Returns all metadata associated with this stack')
     .command('init [TEMPLATE]', 'Create a new, empty CDK project from a template. Invoked without TEMPLATE, the app template will be used.', yargs => yargs
       .option('language', { type: 'string', alias: 'l', desc: 'The language to be used for the new project (default can be configured in ~/.cdk.json)', choices: initTemplateLanuages })
@@ -184,8 +183,7 @@ async function initCommandLine() {
           exclusively: args.exclusively,
           templatePath: args.template,
           strict: args.strict,
-          contextLines: args.contextLines,
-          fail: args.fail
+          contextLines: args.contextLines
         });
 
       case 'bootstrap':

packages/aws-cdk/lib/cdk-toolkit.ts

@@ -51,7 +51,7 @@ export class CdkToolkit {
     const contextLines = options.contextLines || 3;
     const stream = options.stream || process.stderr;
 
-    let diffs = 0;
+    let ret = 0;
     if (options.templatePath !== undefined) {
       // Compare single stack against fixed template
       if (stacks.length !== 1) {
@@ -62,17 +62,19 @@ export class CdkToolkit {
         throw new Error(`There is no file at ${options.templatePath}`);
       }
       const template = deserializeStructure(await fs.readFile(options.templatePath, { encoding: 'UTF-8' }));
-      diffs = printStackDiff(template, stacks[0], strict, contextLines, stream);
+      ret = printStackDiff(template, stacks[0], strict, contextLines, options.stream);
     } else {
       // Compare N stacks against deployed templates
       for (const stack of stacks) {
         stream.write(format('Stack %s\n', colors.bold(stack.name)));
         const currentTemplate = await this.provisioner.readCurrentTemplate(stack);
-        diffs = printStackDiff(currentTemplate, stack, strict, contextLines, stream);
+        if (printStackDiff(currentTemplate, stack, !!options.strict, options.contextLines || 3, stream) !== 0) {
+          ret = 1;
+        }
       }
     }
 
-    return diffs && options.fail ? 1 : 0;
+    return ret;
   }
 
   public async deploy(options: DeployOptions) {
@@ -245,13 +247,6 @@ export interface DiffOptions {
    * @default stderr
    */
   stream?: NodeJS.WritableStream;
-
-  /**
-   * Whether to fail with exit code 1 in case of diff
-   *
-   * @default false
-   */
-  fail?: boolean;
 }
 
 export interface DeployOptions {

packages/aws-cdk/test/integ/cli/test-cdk-diff.sh

@@ -6,14 +6,11 @@ source ${scriptdir}/common.bash
 
 setup
 
-cdk diff ${STACK_NAME_PREFIX}-test-1 2>&1 | grep "AWS::SNS::Topic"
-cdk diff ${STACK_NAME_PREFIX}-test-2 2>&1 | grep "AWS::SNS::Topic"
+function cdk_diff() {
+    cdk diff $1 2>&1 || true
+}
 
-fail=0
-cdk diff --fail ${STACK_NAME_PREFIX}-test-1 2>&1 || fail=1
-
-if [ $fail -ne 1 ]; then
-  fail 'cdk diff with --fail does not fail'
-fi
+cdk_diff ${STACK_NAME_PREFIX}-test-1 | grep "AWS::SNS::Topic"
+cdk_diff ${STACK_NAME_PREFIX}-test-2 | grep "AWS::SNS::Topic"
 
 echo "✅  success"

packages/aws-cdk/test/integ/cli/test-cdk-iam-diff.sh

@@ -7,7 +7,7 @@ source ${scriptdir}/common.bash
 setup
 
 function nonfailing_diff() {
-    cdk diff $1 2>&1 | strip_color_codes
+    ( cdk diff $1 2>&1 || true ) | strip_color_codes
 }
 
 assert "nonfailing_diff ${STACK_NAME_PREFIX}-iam-test" <<HERE

packages/aws-cdk/test/test.diff.ts

@@ -53,32 +53,6 @@ export = {
     test.ok(plainTextOutput.indexOf('Stack A') > -1, `Did not contain "Stack A": ${plainTextOutput}`);
     test.ok(plainTextOutput.indexOf('Stack B') > -1, `Did not contain "Stack B": ${plainTextOutput}`);
 
-    test.equals(0, exitCode);
-
-    test.done();
-  },
-
-  async 'exits with 1 with diffs and fail set to true'(test: Test) {
-    // GIVEN
-    const provisioner: IDeploymentTarget = {
-      async readCurrentTemplate(_stack: cxapi.CloudFormationStackArtifact): Promise<Template> {
-        return {};
-      },
-      async deployStack(_options: DeployStackOptions): Promise<DeployStackResult> {
-        return { noOp: true, outputs: {}, stackArn: ''};
-      }
-    };
-    const toolkit = new CdkToolkit({ appStacks, provisioner });
-    const buffer = new StringWritable();
-
-    // WHEN
-    const exitCode = await toolkit.diff({
-      stackNames: ['A'],
-      stream: buffer,
-      fail: true
-    });
-
-    // THEN
     test.equals(1, exitCode);
 
     test.done();