fix(cdk): CfnMapping.findInMap with tokens (#2531)

Do not validate existence of second key if the first
key is a token.

Fixes #1363

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

@@ -38,8 +38,8 @@ export class CfnMapping extends CfnRefElement {
  throw new Error(`Mapping doesn't contain top-level key '${key1}'`);
  }
 
- // opportunistically check that the key exists (if the key does not contain tokens)
- if (!Token.isToken(key2) && !(key2 in this.mapping[key1])) {
+ // opportunistically check that the second key exists (if the key does not contain tokens)
+ if (!Token.isToken(key1) && !Token.isToken(key2) && !(key2 in this.mapping[key1])) {
  throw new Error(`Mapping doesn't contain second-level key '${key2}'`);
  }
 

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

@@ -62,5 +62,46 @@ export = {
  test.deepEqual(stack.node.resolve(v1), expected);
  test.deepEqual(stack.node.resolve(v2), expected);
  test.done();
- }
+ },
+
+ 'no validation if first key is token and second is a static string'(test: Test) {
+ // GIVEN
+ const stack = new Stack();
+ const mapping = new CfnMapping(stack, 'mapping', {
+ mapping: {
+ 'us-east-1': {
+ size: 12
+ }
+ }
+ });
+
+ // WHEN
+ const v = mapping.findInMap(Aws.region, 'size');
+
+ // THEN
+ test.deepEqual(stack.node.resolve(v), {
+ "Fn::FindInMap": [ 'mapping', { Ref: "AWS::Region" }, "size" ]
+ });
+ test.done();
+ },
+
+ 'validate first key if it is a string and second is a token'(test: Test) {
+ // GIVEN
+ const stack = new Stack();
+ const mapping = new CfnMapping(stack, 'mapping', {
+ mapping: {
+ size: {
+ 'us-east-1': 12
+ }
+ }
+ });
+
+ // WHEN
+ const v = mapping.findInMap('size', Aws.region);
+
+ // THEN
+ test.throws(() => mapping.findInMap('not-found', Aws.region), /Mapping doesn't contain top-level key 'not-found'/);
+ test.deepEqual(stack.node.resolve(v), { 'Fn::FindInMap': [ 'mapping', 'size', { Ref: 'AWS::Region' } ] });
+ test.done();
+ },
 };