Merge #10537: Few Minor per-utxo assert-semantics re-adds and tweak

9417d7a33 Be much more agressive in AccessCoin docs. (Matt Corallo)
f58349ca8 Restore some assert semantics in sigop cost calculations (Matt Corallo)
3533fb4d3 Return a bool in SpendCoin to restore pre-per-utxo assert semantics (Matt Corallo)
ec1271f2b Remove useless mapNextTx lookup in CTxMemPool::TrimToSize. (Matt Corallo)

Tree-SHA512: 158a4bce063eac93e1d50709500a10a7cb1fb3271f10ed445d701852fce713e2bf0da3456088e530ab005f194ef4a2adf0c7cb23226b160cecb37a79561f29ca

1 files changed, 8 insertions, 3 deletions

diff --git a/src/coins.h b/src/coins.h
index dc3210b8ac..4774c9f6a6 100644
--- a/src/coins.h
+++ b/src/coins.h
@@ -224,8 +224,13 @@ public:
 
     /**
      * Return a reference to Coin in the cache, or a pruned one if not found. This is
-     * more efficient than GetCoin. Modifications to other cache entries are
-     * allowed while accessing the returned pointer.
+     * more efficient than GetCoin.
+     *
+     * Generally, do not hold the reference returned for more than a short scope.
+     * While the current implementation allows for modifications to the contents
+     * of the cache while holding the reference, this behavior should not be relied
+     * on! To be safe, best to not hold the returned reference through any other
+     * calls to this cache.
      */
     const Coin& AccessCoin(const COutPoint &output) const;
 
@@ -240,7 +245,7 @@ public:
      * If no unspent output exists for the passed outpoint, this call
      * has no effect.
      */
-    void SpendCoin(const COutPoint &outpoint, Coin* moveto = nullptr);
+    bool SpendCoin(const COutPoint &outpoint, Coin* moveto = nullptr);
 
     /**
      * Push the modifications applied to this cache to its base.