feat(core): implicit app for root stacks

When a stack is created as the root of the construct tree, we now implicitly create an `App` that serves as its parent scope.

The root stack is created with the ID `Default`, which ensures that `node.uniqueId` of constructs within that stack is preserved.

BREAKING CHANGE: in unit tests, the `node.path` of constructs within stacks created the root of the tree via `new Stack()` will now have a prefix `Default/` which represents an implicit `App` root.

Related: aws/aws-cdk-rfcs#192

packages/@aws-cdk/assert/lib/synth-utils.ts

@@ -4,13 +4,12 @@ import * as core from '@aws-cdk/core';
 import * as cxapi from '@aws-cdk/cx-api';
 
 export class SynthUtils {
+  /**
+   * Returns the cloud assembly template artifact for a stack.
+   */
   public static synthesize(stack: core.Stack, options: core.SynthesisOptions = { }): cxapi.CloudFormationStackArtifact {
     // always synthesize against the root (be it an App or whatever) so all artifacts will be included
-    const root = stack.node.root;
-
-    // if the root is an app, invoke "synth" to avoid double synthesis
-    const assembly = root instanceof core.App ? root.synth() : core.ConstructNode.synth(root.node, options);
-
+    const assembly = synthesizeApp(stack, options);
     return assembly.getStackArtifact(stack.artifactId);
   }
 
@@ -51,10 +50,7 @@ export class SynthUtils {
    */
   public static _synthesizeWithNested(stack: core.Stack, options: core.SynthesisOptions = { }): cxapi.CloudFormationStackArtifact | object {
     // always synthesize against the root (be it an App or whatever) so all artifacts will be included
-    const root = stack.node.root;
-
-    // if the root is an app, invoke "synth" to avoid double synthesis
-    const assembly = root instanceof core.App ? root.synth() : core.ConstructNode.synth(root.node, options);
+    const assembly = synthesizeApp(stack, options);
 
     // if this is a nested stack (it has a parent), then just read the template as a string
     if (stack.nestedStackParent) {
@@ -65,6 +61,24 @@ export class SynthUtils {
   }
 }
 
+/**
+ * Synthesizes the app in which a stack resides and returns the cloud assembly object.
+ */
+function synthesizeApp(stack: core.Stack, options: core.SynthesisOptions) {
+  const root = stack.node.root;
+  if (!core.Stage.isStage(root)) {
+    throw new Error('unexpected: all stacks must be part of a Stage or an App');
+  }
+
+  // to support incremental assertions (i.e. "expect(stack).toNotContainSomething(); doSomething(); expect(stack).toContainSomthing()")
+  const force = true;
+
+  return root.synth({
+    force,
+    ...options,
+  });
+}
+
 export interface SubsetOptions {
   /**
    * Match all resources of the given type

packages/@aws-cdk/aws-apigateway/test/integ.restapi.multistack.expected.json

@@ -120,7 +120,7 @@
           "BooksApi60AC975F"
         ]
       },
-      "BooksApiDeployment86CA39AFc1570c78b1ea90526c0309cd74b7b8d0": {
+      "BooksApiDeployment86CA39AF4ff82f86c127f53c9de94d266b1906be": {
         "Type": "AWS::ApiGateway::Deployment",
         "Properties": {
           "RestApiId": {
@@ -141,7 +141,7 @@
             "Ref": "BooksApi60AC975F"
           },
           "DeploymentId": {
-            "Ref": "BooksApiDeployment86CA39AFc1570c78b1ea90526c0309cd74b7b8d0"
+            "Ref": "BooksApiDeployment86CA39AF4ff82f86c127f53c9de94d266b1906be"
           },
           "StageName": "prod"
         }

packages/@aws-cdk/aws-apigateway/test/test.deployment.ts

@@ -150,16 +150,16 @@ export = {
     // the logical ID changed
     const template = synthesize();
     test.ok(!template.Resources.deployment33381975bba46c5132329b81e7befcbbba5a0e75, 'old resource id is not deleted');
-    test.ok(template.Resources.deployment33381975075f46a4503208d69fcffed2f263c48c,
-      `new resource deployment33381975075f46a4503208d69fcffed2f263c48c is not created, instead found ${Object.keys(template.Resources)}`);
+    test.ok(template.Resources.deployment333819758aa4cdb9d204502b959c4903f4d5d29f,
+      `new resource deployment333819758aa4cdb9d204502b959c4903f4d5d29f is not created, instead found ${Object.keys(template.Resources)}`);
 
     // tokens supported, and are resolved upon synthesis
     const value = 'hello hello';
     deployment.addToLogicalId({ foo: Lazy.stringValue({ produce: () => value }) });
 
     const template2 = synthesize();
-    test.ok(template2.Resources.deployment33381975b6d7672e4c9afd0b741e41d07739786b,
-      `resource deployment33381975b6d7672e4c9afd0b741e41d07739786b not found, instead found ${Object.keys(template2.Resources)}`);
+    test.ok(template2.Resources.deployment333819758d91bed959c6bd6268ba84f6d33e888e,
+      `resource deployment333819758d91bed959c6bd6268ba84f6d33e888e not found, instead found ${Object.keys(template2.Resources)}`);
 
     test.done();
 

packages/@aws-cdk/aws-autoscaling/test/auto-scaling-group.test.ts

@@ -32,7 +32,7 @@ nodeunitShim({
         'MyFleetInstanceSecurityGroup774E8234': {
           'Type': 'AWS::EC2::SecurityGroup',
           'Properties': {
-            'GroupDescription': 'MyFleet/InstanceSecurityGroup',
+            'GroupDescription': 'TestStack/MyFleet/InstanceSecurityGroup',
             'SecurityGroupEgress': [
               {
                 'CidrIp': '0.0.0.0/0',
@@ -43,7 +43,7 @@ nodeunitShim({
             'Tags': [
               {
                 'Key': 'Name',
-                'Value': 'MyFleet',
+                'Value': 'TestStack/MyFleet',
               },
             ],
 
@@ -68,7 +68,7 @@ nodeunitShim({
             'Tags': [
               {
                 'Key': 'Name',
-                'Value': 'MyFleet',
+                'Value': 'TestStack/MyFleet',
               },
             ],
           },
@@ -122,7 +122,7 @@ nodeunitShim({
               {
                 'Key': 'Name',
                 'PropagateAtLaunch': true,
-                'Value': 'MyFleet',
+                'Value': 'TestStack/MyFleet',
               },
             ],
 
@@ -520,7 +520,7 @@ nodeunitShim({
         {
           Key: 'Name',
           PropagateAtLaunch: true,
-          Value: 'MyFleet',
+          Value: 'TestStack/MyFleet',
         },
         {
           Key: 'notsuper',

packages/@aws-cdk/aws-autoscaling/test/scheduled-action.test.ts

@@ -69,7 +69,7 @@ nodeunitShim({
               {
                 Key: 'Name',
                 PropagateAtLaunch: true,
-                Value: 'ASG',
+                Value: 'Default/ASG',
               },
             ],
             VPCZoneIdentifier: [

packages/@aws-cdk/aws-codecommit/test/test.codecommit.ts

@@ -29,7 +29,7 @@ export = {
                     'all',
                   ],
                   DestinationArn: 'arn:aws:sns:*:123456789012:my_topic',
-                  Name: 'MyRepository/arn:aws:sns:*:123456789012:my_topic',
+                  Name: 'Default/MyRepository/arn:aws:sns:*:123456789012:my_topic',
                 },
               ],
             },

packages/@aws-cdk/aws-dynamodb/test/dynamodb.test.ts

@@ -718,7 +718,7 @@ test('if an encryption key is included, encrypt/decrypt permissions are also add
             ],
             'Version': '2012-10-17',
           },
-          'Description': 'Customer-managed key auto-created for encrypting DynamoDB table at Table A',
+          'Description': 'Customer-managed key auto-created for encrypting DynamoDB table at Default/Table A',
           'EnableKeyRotation': true,
         },
         'UpdateReplacePolicy': 'Retain',
@@ -1755,7 +1755,7 @@ describe('grants', () => {
     const user = new iam.User(stack, 'user');
 
     // WHEN
-    expect(() => table.grantTableListStreams(user)).toThrow(/DynamoDB Streams must be enabled on the table my-table/);
+    expect(() => table.grantTableListStreams(user)).toThrow(/DynamoDB Streams must be enabled on the table Default\/my-table/);
   });
 
   test('"grantTableListStreams" allows principal to list all streams for this table', () => {
@@ -1801,7 +1801,7 @@ describe('grants', () => {
     const user = new iam.User(stack, 'user');
 
     // WHEN
-    expect(() => table.grantStreamRead(user)).toThrow(/DynamoDB Streams must be enabled on the table my-table/);
+    expect(() => table.grantStreamRead(user)).toThrow(/DynamoDB Streams must be enabled on the table Default\/my-table/);
   });
 
   test('"grantStreamRead" allows principal to read and describe the table stream"', () => {

packages/@aws-cdk/aws-ec2/test/connections.test.ts

@@ -78,7 +78,7 @@ nodeunitShim({
 
     // THEN
     expect(stack).to(haveResource('AWS::EC2::SecurityGroup', {
-      GroupDescription: 'SecurityGroup1',
+      GroupDescription: 'Default/SecurityGroup1',
       SecurityGroupIngress: [
         {
           Description: 'from 0.0.0.0/0:88',
@@ -91,7 +91,7 @@ nodeunitShim({
     }));
 
     expect(stack).to(haveResource('AWS::EC2::SecurityGroup', {
-      GroupDescription: 'SecurityGroup2',
+      GroupDescription: 'Default/SecurityGroup2',
       SecurityGroupIngress: [
         {
           Description: 'from 0.0.0.0/0:88',

packages/@aws-cdk/aws-ec2/test/userdata.test.ts

@@ -52,7 +52,7 @@ nodeunitShim({
 
     test.equals(rendered, '<powershell>trap {\n' +
         '$success=($PSItem.Exception.Message -eq "Success")\n' +
-        'cfn-signal --stack Stack --resource RESOURCE1989552F --region ${Token[AWS::Region.4]} --success ($success.ToString().ToLower())\n' +
+        'cfn-signal --stack Default --resource RESOURCE1989552F --region ${Token[AWS::Region.4]} --success ($success.ToString().ToLower())\n' +
         'break\n' +
         '}\n' +
         'command1\n' +
@@ -157,7 +157,7 @@ nodeunitShim({
     test.equals(rendered, '#!/bin/bash\n' +
         'function exitTrap(){\n' +
         'exitCode=$?\n' +
-        '/opt/aws/bin/cfn-signal --stack Stack --resource RESOURCE1989552F --region ${Token[AWS::Region.4]} -e $exitCode || echo \'Failed to send Cloudformation Signal\'\n' +
+        '/opt/aws/bin/cfn-signal --stack Default --resource RESOURCE1989552F --region ${Token[AWS::Region.4]} -e $exitCode || echo \'Failed to send Cloudformation Signal\'\n' +
         '}\n' +
         'trap exitTrap EXIT\n' +
         'command1');

packages/@aws-cdk/aws-ec2/test/vpc-endpoint.test.ts

@@ -260,7 +260,7 @@ nodeunitShim({
       }));
 
       expect(stack).to(haveResource('AWS::EC2::SecurityGroup', {
-        GroupDescription: 'VpcNetwork/EcrDocker/SecurityGroup',
+        GroupDescription: 'Default/VpcNetwork/EcrDocker/SecurityGroup',
         VpcId: {
           Ref: 'VpcNetworkB258E83A',
         },

packages/@aws-cdk/aws-ec2/test/vpc.test.ts

@@ -32,11 +32,11 @@ nodeunitShim({
         new Vpc(stack, 'TheVPC');
         expect(stack).to(
           haveResource('AWS::EC2::VPC',
-            hasTags( [ {Key: 'Name', Value: 'TheVPC'} ])),
+            hasTags( [ {Key: 'Name', Value: 'TestStack/TheVPC'} ])),
         );
         expect(stack).to(
           haveResource('AWS::EC2::InternetGateway',
-            hasTags( [ {Key: 'Name', Value: 'TheVPC'} ])),
+            hasTags( [ {Key: 'Name', Value: 'TestStack/TheVPC'} ])),
         );
         test.done();
       },
@@ -458,7 +458,7 @@ nodeunitShim({
       for (let i = 1; i < 4; i++) {
         expect(stack).to(haveResource('AWS::EC2::Subnet', hasTags([{
           Key: 'Name',
-          Value: `VPC/egressSubnet${i}`,
+          Value: `TestStack/VPC/egressSubnet${i}`,
         }, {
           Key: 'aws-cdk:subnet-name',
           Value: 'egress',

packages/@aws-cdk/aws-ecs/test/fargate/test.fargate-service.ts

@@ -66,7 +66,7 @@ export = {
       }));
 
       expect(stack).to(haveResource('AWS::EC2::SecurityGroup', {
-        GroupDescription: 'FargateService/SecurityGroup',
+        GroupDescription: 'Default/FargateService/SecurityGroup',
         SecurityGroupEgress: [
           {
             CidrIp: '0.0.0.0/0',
@@ -897,7 +897,7 @@ export = {
               protocol: ecs.Protocol.TCP,
             })],
           });
-        }, /Container 'FargateTaskDef\/MainContainer' has no mapping for port 8001 and protocol tcp. Did you call "container.addPortMappings\(\)"\?/);
+        }, /Container 'Default\/FargateTaskDef\/MainContainer' has no mapping for port 8001 and protocol tcp. Did you call "container.addPortMappings\(\)"\?/);
 
         test.done();
       },
@@ -932,7 +932,7 @@ export = {
               containerPort: 8002,
             })],
           });
-        }, /Container 'FargateTaskDef\/MainContainer' has no mapping for port 8002 and protocol tcp. Did you call "container.addPortMappings\(\)"\?/);
+        }, /Container 'Default\/FargateTaskDef\/MainContainer' has no mapping for port 8002 and protocol tcp. Did you call "container.addPortMappings\(\)"\?/);
 
         test.done();
       },