From ee1e40f58000921e95f08bcb199a452eb5c4d9b2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C5=91rinc?= <pap.lorinc@gmail.com>
Date: Sat, 3 Jan 2026 20:26:04 +0100
Subject: [PATCH] txdb: assert `CCoinsViewDB::GetCoin` only returns unspent
 coins

The chainstate UTXO database only stores unspent outputs; spent entries are removed.

Assert after reading a `Coin` so corruption or misuse cannot propagate a spent coin through the `GetCoin()` interface.
---
 src/txdb.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/txdb.cpp b/src/txdb.cpp
index 5d61388b078..141c31c5d51 100644
--- a/src/txdb.cpp
+++ b/src/txdb.cpp
@@ -67,7 +67,10 @@ void CCoinsViewDB::ResizeCache(size_t new_cache_size)
 
 std::optional<Coin> CCoinsViewDB::GetCoin(const COutPoint& outpoint) const
 {
-    if (Coin coin; m_db->Read(CoinEntry(&outpoint), coin)) return coin;
+    if (Coin coin; m_db->Read(CoinEntry(&outpoint), coin)) {
+        Assert(!coin.IsSpent()); // The UTXO database should never contain spent coins
+        return coin;
+    }
     return std::nullopt;
 }