From 46745f7f1290c59c2bec0ca76dd138aacb430cef Mon Sep 17 00:00:00 2001
From: Dave Collins <davec@conformal.com>
Date: Wed, 6 May 2026 01:18:38 -0500
Subject: [PATCH] blockchain: Cleanup proof of stake checks.

This performs some light cleanup of the checkProofOfStake function to
make it more consistent with the rest of the code make the error
messages more accurate and useful.
---
 internal/blockchain/validate.go | 48 ++++++++++++++++-----------------
 1 file changed, 23 insertions(+), 25 deletions(-)

diff --git a/internal/blockchain/validate.go b/internal/blockchain/validate.go
index 216377cb9..4d1986eee 100644
--- a/internal/blockchain/validate.go
+++ b/internal/blockchain/validate.go
@@ -629,32 +629,30 @@ func CheckTransaction(tx *wire.MsgTx, params *chaincfg.Params, flags AgendaFlags
 // checkProofOfStake ensures that all ticket purchases in the block pay at least
 // the amount required by the block header stake bits which indicate the target
 // stake difficulty (aka ticket price) as claimed.
-func checkProofOfStake(block *dcrutil.Block, posLimit int64) error {
-	msgBlock := block.MsgBlock()
-	for _, staketx := range block.STransactions() {
-		msgTx := staketx.MsgTx()
-		if stake.IsSStx(msgTx) {
-			commitValue := msgTx.TxOut[0].Value
-
-			// Check for underflow block sbits.
-			if commitValue < msgBlock.Header.SBits {
-				errStr := fmt.Sprintf("Stake tx %v has a "+
-					"commitment value less than the "+
-					"minimum stake difficulty specified in"+
-					" the block (%v)", staketx.Hash(),
-					msgBlock.Header.SBits)
-				return ruleError(ErrNotEnoughStake, errStr)
-			}
+func checkProofOfStake(block *dcrutil.Block, minStakeDiff int64) error {
+	header := &block.MsgBlock().Header
+	for _, stx := range block.STransactions() {
+		msgTx := stx.MsgTx()
+		if !stake.IsSStx(msgTx) {
+			continue
+		}
 
-			// Check if it's above the PoS limit.
-			if commitValue < posLimit {
-				errStr := fmt.Sprintf("Stake tx %v has a "+
-					"commitment value less than the "+
-					"minimum stake difficulty for the "+
-					"network (%v)", staketx.Hash(),
-					posLimit)
-				return ruleError(ErrStakeBelowMinimum, errStr)
-			}
+		// The ticket price must not be below the stake difficulty claimed by
+		// the block header.
+		ticketPaidAmt := msgTx.TxOut[submissionOutputIdx].Value
+		if ticketPaidAmt < header.SBits {
+			str := fmt.Sprintf("ticket %v pays less than the stake difficulty "+
+				"committed to by the block header (%v < %v)", stx.Hash(),
+				ticketPaidAmt, header.SBits)
+			return ruleError(ErrNotEnoughStake, str)
+		}
+
+		// The ticket price must not be below the network minimum.
+		if ticketPaidAmt < minStakeDiff {
+			str := fmt.Sprintf("ticket %v pays less than the network minimum "+
+				"stake difficulty of (%v < %v)", stx.Hash(), ticketPaidAmt,
+				minStakeDiff)
+			return ruleError(ErrStakeBelowMinimum, str)
 		}
 	}