From 24335d0dd71d11a2a9088c05728ed8507062434d Mon Sep 17 00:00:00 2001
From: Richard Moore <github@ricmoo.com>
Date: Thu, 4 Oct 2018 16:46:19 -0400
Subject: [PATCH] Fix for geth-etc (official geth is fine), which returns
 Receipts before the blockHash is synced to the database.

---
 src.ts/providers/base-provider.ts | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src.ts/providers/base-provider.ts b/src.ts/providers/base-provider.ts
index be214f930..db3a8f04e 100644
--- a/src.ts/providers/base-provider.ts
+++ b/src.ts/providers/base-provider.ts
@@ -980,6 +980,9 @@ export class BaseProvider extends Provider {
                             return undefined;
                         }
 
+                        // "geth-etc" returns receipts before they are ready
+                        if (result.blockHash == null) { return undefined; }
+
                         return checkTransactionReceipt(result);
                     });
                 }, { onceBlock: this });