core: respect price bump threshold (#15401)

* core: allow price bump at threshold

* core: test changes to allow price bump at threshold

* core: reinstate tx replacement test underneath threshold

* core: minor test failure message cleanups

2 files changed, 14 insertions, 11 deletions

diff --git a/core/tx_list.go b/core/tx_list.go
index 2935929d7..838433b89 100644
--- a/core/tx_list.go
+++ b/core/tx_list.go
@@ -254,7 +254,10 @@ func (l *txList) Add(tx *types.Transaction, priceBump uint64) (bool, *types.Tran
 	old := l.txs.Get(tx.Nonce())
 	if old != nil {
 		threshold := new(big.Int).Div(new(big.Int).Mul(old.GasPrice(), big.NewInt(100+int64(priceBump))), big.NewInt(100))
-		if threshold.Cmp(tx.GasPrice()) >= 0 {
+		// Have to ensure that the new gas price is higher than the old gas
+		// price as well as checking the percentage threshold to ensure that
+		// this is accurate for low (Wei-level) gas price replacements
+		if old.GasPrice().Cmp(tx.GasPrice()) >= 0 || threshold.Cmp(tx.GasPrice()) > 0 {
 			return false, nil
 		}
 	}
diff --git a/core/tx_pool_test.go b/core/tx_pool_test.go
index eec128cba..737ea4cd3 100644
--- a/core/tx_pool_test.go
+++ b/core/tx_pool_test.go
@@ -1411,10 +1411,10 @@ func TestTransactionReplacement(t *testing.T) {
 	if err := pool.AddRemote(pricedTransaction(0, big.NewInt(100000), big.NewInt(price), key)); err != nil {
 		t.Fatalf("failed to add original proper pending transaction: %v", err)
 	}
-	if err := pool.AddRemote(pricedTransaction(0, big.NewInt(100000), big.NewInt(threshold), key)); err != ErrReplaceUnderpriced {
+	if err := pool.AddRemote(pricedTransaction(0, big.NewInt(100001), big.NewInt(threshold-1), key)); err != ErrReplaceUnderpriced {
 		t.Fatalf("original proper pending transaction replacement error mismatch: have %v, want %v", err, ErrReplaceUnderpriced)
 	}
-	if err := pool.AddRemote(pricedTransaction(0, big.NewInt(100000), big.NewInt(threshold+1), key)); err != nil {
+	if err := pool.AddRemote(pricedTransaction(0, big.NewInt(100000), big.NewInt(threshold), key)); err != nil {
 		t.Fatalf("failed to replace original proper pending transaction: %v", err)
 	}
 	if err := validateEvents(events, 2); err != nil {
@@ -1422,23 +1422,23 @@ func TestTransactionReplacement(t *testing.T) {
 	}
 	// Add queued transactions, ensuring the minimum price bump is enforced for replacement (for ultra low prices too)
 	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100000), big.NewInt(1), key)); err != nil {
-		t.Fatalf("failed to add original queued transaction: %v", err)
+		t.Fatalf("failed to add original cheap queued transaction: %v", err)
 	}
 	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100001), big.NewInt(1), key)); err != ErrReplaceUnderpriced {
-		t.Fatalf("original queued transaction replacement error mismatch: have %v, want %v", err, ErrReplaceUnderpriced)
+		t.Fatalf("original cheap queued transaction replacement error mismatch: have %v, want %v", err, ErrReplaceUnderpriced)
 	}
 	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100000), big.NewInt(2), key)); err != nil {
-		t.Fatalf("failed to replace original queued transaction: %v", err)
+		t.Fatalf("failed to replace original cheap queued transaction: %v", err)
 	}
 
 	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100000), big.NewInt(price), key)); err != nil {
-		t.Fatalf("failed to add original queued transaction: %v", err)
+		t.Fatalf("failed to add original proper queued transaction: %v", err)
 	}
-	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100001), big.NewInt(threshold), key)); err != ErrReplaceUnderpriced {
-		t.Fatalf("original queued transaction replacement error mismatch: have %v, want %v", err, ErrReplaceUnderpriced)
+	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100001), big.NewInt(threshold-1), key)); err != ErrReplaceUnderpriced {
+		t.Fatalf("original proper queued transaction replacement error mismatch: have %v, want %v", err, ErrReplaceUnderpriced)
 	}
-	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100000), big.NewInt(threshold+1), key)); err != nil {
-		t.Fatalf("failed to replace original queued transaction: %v", err)
+	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100000), big.NewInt(threshold), key)); err != nil {
+		t.Fatalf("failed to replace original proper queued transaction: %v", err)
 	}
 
 	if err := validateEvents(events, 0); err != nil {