1 files changed, 12 insertions, 3 deletions

diff --git a/src/main.h b/src/main.h
index 1f452b5..30e25ef 100644
--- a/src/main.h
+++ b/src/main.h
@@ -43,15 +43,24 @@ static const unsigned int MAX_BLOCK_SIZE = 1000000;
 static const unsigned int MAX_BLOCK_SIZE_GEN = MAX_BLOCK_SIZE / 2;
 
 // Room for one more transaction in a template that currently weighs
-// nBlockSize bytes?
+// nBlockSize bytes and spends nBlockSigOps signature operations?
 //
 // Asked BEFORE the transaction is appended, never after. A template that has
 // already overshot is one CheckBlock() rejects, and asking afterwards only
 // measures the waste. Both assemblers call this, so neither can drift into a
 // different idea of what fits.
-inline bool BlockTemplateFits(unsigned int nBlockSize, unsigned int nTxSize)
+//
+// Size gets a margin (half the cap); sigops do not. There is no cheap way to
+// spend the sigop budget usefully and no reason to reserve headroom in it, so
+// assembly holds itself to the same number CheckBlock() enforces -- and to the
+// same comparison. CheckBlock() fails on `> MAX_BLOCK_SIGOPS`, so a block
+// sitting exactly on the limit is valid and this has to accept it too.
+// Assembly and validation disagreeing by one is how the size bug started.
+inline bool BlockTemplateFits(unsigned int nBlockSize, unsigned int nBlockSigOps,
+                              unsigned int nTxSize, unsigned int nTxSigOps)
 {
-    return (nBlockSize + nTxSize <= MAX_BLOCK_SIZE_GEN);
+    return (nBlockSize + nTxSize <= MAX_BLOCK_SIZE_GEN &&
+            nBlockSigOps + nTxSigOps <= MAX_BLOCK_SIGOPS);
 }
 static const int64 COIN = 100000000;
 // Total Bitflash emission: identical to Bitcoin (21 million).