fix(core): make IResolvable.creationStack required

packages/@aws-cdk/aws-events/lib/input.ts

@@ -1,5 +1,5 @@
-import { DefaultTokenResolver, IResolvable, IResolveContext,
-  Lazy, Stack, StringConcat, Token, Tokenization } from '@aws-cdk/cdk';
+import { captureStackTrace, DefaultTokenResolver, IResolvable,
+  IResolveContext, Lazy, Stack, StringConcat, Token, Tokenization } from '@aws-cdk/cdk';
 import { IRule } from './rule-ref';
 
 /**
@@ -274,10 +274,12 @@ export class EventField implements IResolvable {
   }
 
   public readonly displayHint: string;
+  public readonly creationStack: string[];
 
   private constructor(public readonly path: string) {
     this.displayHint = this.path.replace(/^[^a-zA-Z0-9_-]+/, '').replace(/[^a-zA-Z0-9_-]/g, '-');
     Object.defineProperty(this, EVENT_FIELD_SYMBOL, { value: true });
+    this.creationStack = captureStackTrace();
   }
 
   public resolve(_ctx: IResolveContext): any {

packages/@aws-cdk/aws-iam/lib/policy-document.ts

@@ -1,5 +1,5 @@
 import cdk = require('@aws-cdk/cdk');
-import { IPostProcessor } from '@aws-cdk/cdk';
+import { captureStackTrace, IPostProcessor } from '@aws-cdk/cdk';
 import { PolicyStatement } from './policy-statement';
 
 /**
@@ -25,10 +25,12 @@ export interface PolicyDocumentProps {
  * A PolicyDocument is a collection of statements
  */
 export class PolicyDocument implements cdk.IResolvable {
+  public readonly creationStack: string[];
   private readonly statements = new Array<PolicyStatement>();
   private readonly autoAssignSids: boolean;
 
   constructor(props: PolicyDocumentProps = {}) {
+    this.creationStack = captureStackTrace();
     this.autoAssignSids = !!props.assignSids;
 
     this.addStatements(...props.statements || []);

packages/@aws-cdk/aws-iam/lib/principals.ts

@@ -1,5 +1,5 @@
 import cdk = require('@aws-cdk/cdk');
-import { Stack } from '@aws-cdk/cdk';
+import { captureStackTrace, Stack } from '@aws-cdk/cdk';
 import { Default, RegionInfo } from '@aws-cdk/region-info';
 import { PolicyStatement } from './policy-statement';
 import { mergePrincipal } from './util';
@@ -312,7 +312,9 @@ export class CompositePrincipal extends PrincipalBase {
  * A lazy token that requires an instance of Stack to evaluate
  */
 class StackDependentToken implements cdk.IResolvable {
+  public readonly creationStack: string[];
   constructor(private readonly fn: (stack: cdk.Stack) => any) {
+    this.creationStack = captureStackTrace();
   }
 
   public resolve(context: cdk.IResolveContext) {
@@ -329,8 +331,10 @@ class StackDependentToken implements cdk.IResolvable {
 }
 
 class ServicePrincipalToken implements cdk.IResolvable {
+  public readonly creationStack: string[];
   constructor(private readonly service: string,
               private readonly opts: ServicePrincipalOpts) {
+    this.creationStack = captureStackTrace();
   }
 
   public resolve(ctx: cdk.IResolveContext) {

packages/@aws-cdk/aws-stepfunctions/lib/json-path.ts

@@ -1,4 +1,4 @@
-import { IResolvable, IResolveContext, Token, Tokenization } from '@aws-cdk/cdk';
+import { captureStackTrace, IResolvable, IResolveContext, Token, Tokenization } from '@aws-cdk/cdk';
 
 const JSON_PATH_TOKEN_SYMBOL = Symbol.for('@aws-cdk/aws-stepfunctions.JsonPathToken');
 
@@ -7,9 +7,11 @@ export class JsonPathToken implements IResolvable {
     return (x as any)[JSON_PATH_TOKEN_SYMBOL] === true;
   }
 
+  public readonly creationStack: string[];
   public displayHint: string;
 
   constructor(public readonly path: string) {
+    this.creationStack = captureStackTrace();
     this.displayHint = path.replace(/^[^a-zA-Z]+/, '');
     Object.defineProperty(this, JSON_PATH_TOKEN_SYMBOL, { value: true });
   }

packages/@aws-cdk/cdk/lib/cfn-element.ts

@@ -77,7 +77,7 @@ export abstract class CfnElement extends Construct {
    *      from the +metadata+ entry typed +aws:cdk:logicalId+, and with the bottom-most
    *      node +internal+ entries filtered.
    */
-  public get creationStackTrace(): string[] | undefined {
+  public get creationStack(): string[] | undefined {
     const trace = this.node.metadata.find(md => md.type === cxapi.LOGICAL_ID_METADATA_KEY)!.trace;
     if (!trace) {
       return undefined;

packages/@aws-cdk/cdk/lib/cfn-resource.ts

@@ -248,7 +248,7 @@ export class CfnResource extends CfnRefElement {
       // Change message
       e.message = `While synthesizing ${this.node.path}: ${e.message}`;
       // Adjust stack trace (make it look like node built it, too...)
-      const trace = this.creationStackTrace;
+      const trace = this.creationStack;
       if (trace) {
         const creationStack = ['--- resource created at ---', ...trace].join('\n  at ');
         const problemTrace = e.stack.substr(e.stack.indexOf(e.message) + e.message.length);

packages/@aws-cdk/cdk/lib/construct.ts

@@ -1,8 +1,8 @@
 import cxapi = require('@aws-cdk/cx-api');
 import { IAspect } from './aspect';
 import { DependableTrait, IDependable } from './dependency';
-import { createStackTrace } from './private/stack-trace';
 import { IResolvable } from './resolvable';
+import { captureStackTrace } from './stack-trace';
 import { Token } from './token';
 import { makeUniqueId } from './uniqueid';
 
@@ -312,7 +312,7 @@ export class ConstructNode {
       return;
     }
 
-    const trace = this.tryGetContext(cxapi.DISABLE_METADATA_STACK_TRACE) ? undefined : createStackTrace(from || this.addMetadata);
+    const trace = this.tryGetContext(cxapi.DISABLE_METADATA_STACK_TRACE) ? undefined : captureStackTrace(from || this.addMetadata);
     this._metadata.push({ type, data, trace });
   }
 

packages/@aws-cdk/cdk/lib/fn.ts

@@ -2,6 +2,7 @@ import { ICfnConditionExpression } from './cfn-condition';
 import { minimalCloudFormationJoin } from './cloudformation-lang';
 import { Intrinsic } from './private/intrinsic';
 import { IResolvable, IResolveContext } from './resolvable';
+import { captureStackTrace } from './stack-trace';
 import { Token } from './token';
 
 // tslint:disable:max-line-length
@@ -630,6 +631,8 @@ class FnValueOfAll extends FnBase {
  * with no delimiter.
  */
 class FnJoin implements IResolvable {
+  public readonly creationStack: string[];
+
   private readonly delimiter: string;
   private readonly listOfValues: any[];
   // Cache for the result of resolveValues() - since it otherwise would be computed several times
@@ -648,6 +651,7 @@ class FnJoin implements IResolvable {
 
     this.delimiter = delimiter;
     this.listOfValues = listOfValues;
+    this.creationStack = captureStackTrace();
   }
 
   public resolve(context: IResolveContext): any {

packages/@aws-cdk/cdk/lib/index.ts

@@ -26,6 +26,7 @@ export * from './cfn-dynamic-reference';
 export * from './tag';
 export * from './removal-policy';
 export * from './arn';
+export * from './stack-trace';
 
 export * from './app';
 export * from './context';

packages/@aws-cdk/cdk/lib/lazy.ts

@@ -1,5 +1,5 @@
-import { createStackTrace } from './private/stack-trace';
 import { IResolvable, IResolveContext } from "./resolvable";
+import { captureStackTrace } from './stack-trace';
 import { Token } from "./token";
 
 /**
@@ -123,7 +123,7 @@ abstract class LazyBase implements IResolvable {
   public readonly creationStack: string[];
 
   constructor() {
-    this.creationStack = createStackTrace();
+    this.creationStack = captureStackTrace();
   }
 
   public abstract resolve(context: IResolveContext): any;

packages/@aws-cdk/cdk/lib/private/cross-environment-token.ts

@@ -2,6 +2,7 @@ import { ArnComponents } from '../arn';
 import { IResolvable, IResolveContext } from '../resolvable';
 import { IResource } from '../resource';
 import { Stack } from '../stack';
+import { captureStackTrace } from '../stack-trace';
 
 /**
  * A Token that represents a reference that spans accounts and/or regions,
@@ -11,6 +12,8 @@ import { Stack } from '../stack';
  * This class is private to the @aws-cdk/cdk package.
  */
 export abstract class CrossEnvironmentToken implements IResolvable {
+  public readonly creationStack: string[];
+
   /**
    * @param regularValue the value used when this is referenced NOT from a cross account and/or region Stack
    * @param crossEnvironmentValue the value used when this is referenced from a cross account and/or region Stack
@@ -20,6 +23,7 @@ export abstract class CrossEnvironmentToken implements IResolvable {
   protected constructor(private readonly regularValue: string, private readonly crossEnvironmentValue: any,
                         private readonly resource: IResource) {
     this.resource = resource;
+    this.creationStack = captureStackTrace();
   }
 
   public resolve(context: IResolveContext): any {

packages/@aws-cdk/cdk/lib/private/intrinsic.ts

@@ -1,6 +1,6 @@
 import { IResolvable, IResolveContext } from "../resolvable";
+import { captureStackTrace } from "../stack-trace";
 import { Token } from "../token";
-import { createStackTrace } from "./stack-trace";
 
 /**
  * Token subclass that represents values intrinsic to the target document language
@@ -25,7 +25,7 @@ export class Intrinsic implements IResolvable {
       throw new Error(`Argument to Intrinsic must be a plain value object, got ${value}`);
     }
 
-    this.creationStack = createStackTrace();
+    this.creationStack = captureStackTrace();
     this.value = value;
   }
 

packages/@aws-cdk/cdk/lib/resolvable.ts

@@ -32,8 +32,11 @@ export interface IResolvable {
   /**
    * The creation stack of this resolvable which will be appended to errors
    * thrown during resolution.
+   *
+   * If this returns an empty array or `undefined` the stack will not be
+   * attached.
    */
-  readonly creationStack?: string[];
+  readonly creationStack: string[] | undefined;
 
   /**
    * Produce the Token's value at resolution time

packages/@aws-cdk/cdk/lib/private/stack-trace.ts → packages/@aws-cdk/cdk/lib/stack-trace.ts

@@ -1,6 +1,6 @@
 // tslint:disable-next-line:ban-types
-export function createStackTrace(below?: Function): string[] {
-  below = below || createStackTrace; // hide myself if nothing else
+export function captureStackTrace(below?: Function): string[] {
+  below = below || captureStackTrace; // hide myself if nothing else
   const object = { stack: '' };
   const previousLimit = Error.stackTraceLimit;
   try {

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

@@ -602,6 +602,8 @@ export = {
 };
 
 class Promise2 implements IResolvable {
+  public readonly creationStack = [];
+
   public resolve() {
     return {
       Data: {
@@ -614,6 +616,7 @@ class Promise2 implements IResolvable {
 }
 
 class Promise1 implements IResolvable {
+  public readonly creationStack = [];
   public p2 = [ new Promise2(), new Promise2() ];
 
   public resolve() {