From 0317c192e57d6e7ea5015ee44094a825d843fb25 Mon Sep 17 00:00:00 2001
From: Andreas Schildbach <andreas.schildbach@bloq.com>
Date: Sun, 17 Feb 2019 11:56:25 +0100
Subject: [PATCH] Script: Fix getNumberOfBytesRequiredToSpend() for P2WPKH.

---
 core/src/main/java/org/bitcoinj/script/Script.java | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/core/src/main/java/org/bitcoinj/script/Script.java b/core/src/main/java/org/bitcoinj/script/Script.java
index d22d9e3e4..952c449ca 100644
--- a/core/src/main/java/org/bitcoinj/script/Script.java
+++ b/core/src/main/java/org/bitcoinj/script/Script.java
@@ -619,11 +619,13 @@ public class Script {
             return SIG_SIZE;
         } else if (ScriptPattern.isP2PKH(this)) {
             // scriptSig: <sig> <pubkey>
-            int uncompressedPubKeySize = 65;
+            int uncompressedPubKeySize = 65; // very conservative
             return SIG_SIZE + (pubKey != null ? pubKey.getPubKey().length : uncompressedPubKeySize);
         } else if (ScriptPattern.isP2WPKH(this)) {
             // scriptSig is empty
-            return 0;
+            // witness: <sig> <pubKey>
+            int compressedPubKeySize = 33;
+            return SIG_SIZE + (pubKey != null ? pubKey.getPubKey().length : compressedPubKeySize);
         } else {
             throw new IllegalStateException("Unsupported script type");
         }