From 140268b9298c6b078a37e078ee9756977d0c82e2 Mon Sep 17 00:00:00 2001
From: Mitch Lloyd <mitch.lloyd@gmail.com>
Date: Wed, 8 May 2019 19:01:35 -0700
Subject: [PATCH] Allow CompositePrincipal construction with spread

---
 packages/@aws-cdk/aws-iam/lib/policy-document.ts | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/packages/@aws-cdk/aws-iam/lib/policy-document.ts b/packages/@aws-cdk/aws-iam/lib/policy-document.ts
index 7ebf7565dc6a6..ea315a19d5186 100644
--- a/packages/@aws-cdk/aws-iam/lib/policy-document.ts
+++ b/packages/@aws-cdk/aws-iam/lib/policy-document.ts
@@ -287,11 +287,13 @@ export class CompositePrincipal extends PrincipalBase {
   public readonly assumeRoleAction: string;
   private readonly principals = new Array<PrincipalBase>();
 
-  constructor(principal: PrincipalBase, ...additionalPrincipals: PrincipalBase[]) {
+  constructor(...principals: PrincipalBase[]) {
     super();
-    this.assumeRoleAction = principal.assumeRoleAction;
-    this.addPrincipals(principal);
-    this.addPrincipals(...additionalPrincipals);
+    if (principals.length === 0) {
+      throw new Error('CompositePrincipals must be constructed with at least 1 Principal but none were passed.')
+    }
+    this.assumeRoleAction = principals[0].assumeRoleAction;
+    this.addPrincipals(...principals);
   }
 
   public addPrincipals(...principals: PrincipalBase[]): this {