From 408388c6f157f7b4118cf0f95d38964c6b108578 Mon Sep 17 00:00:00 2001
From: Sarah Heimlich <heimlich@google.com>
Date: Tue, 8 Dec 2020 18:36:05 -0800
Subject: [PATCH] Add error message for CollectionHandle init (#6690)

Add error message for CollectionHandle init

Closes #6690

COPYBARA_INTEGRATE_REVIEW=https://github.com/polymerlabs/arcs/pull/6690 from SHeimlich:collectionHandle dd7e309d7d188d6bccf7a7d196a58e412c4f0772
PiperOrigin-RevId: 346455417
---
 java/arcs/core/entity/CollectionHandle.kt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/java/arcs/core/entity/CollectionHandle.kt b/java/arcs/core/entity/CollectionHandle.kt
index 466950d58bf..2b35c45597c 100644
--- a/java/arcs/core/entity/CollectionHandle.kt
+++ b/java/arcs/core/entity/CollectionHandle.kt
@@ -45,7 +45,9 @@ class CollectionHandle<T : Storable, R : Referencable>(
   private val storageAdapter = config.storageAdapter
 
   init {
-    check(spec.containerType == HandleContainerType.Collection)
+    check(spec.containerType == HandleContainerType.Collection) {
+      "Collection containerType required for CollectionHandle $name, but got ${spec.containerType}."
+    }
   }
 
   // Filter out expired models.