More verbose error message for unsupported or invalid tx type

txpool/txpool.go

@@ -557,7 +557,8 @@ func (p *TxPool) validateTx(tx *types.Transaction) error {
 	if tx.Type == types.StateTx {
 		metrics.IncrCounter([]string{txPoolMetrics, "invalid_tx_type"}, 1)
 
-		return ErrInvalidTxType
+		return fmt.Errorf("%w: type %d rejected, state transactions are not expected to be added to the pool",
+			ErrInvalidTxType, tx.Type)
 	}
 
 	// Check the transaction size to overcome DOS Attacks
@@ -622,7 +623,7 @@ func (p *TxPool) validateTx(tx *types.Transaction) error {
 		if !forks.London {
 			metrics.IncrCounter([]string{txPoolMetrics, "tx_type"}, 1)
 
-			return ErrTxTypeNotSupported
+			return fmt.Errorf("%w: type %d rejected, london hardfork is not enabled", ErrTxTypeNotSupported, tx.Type)
 		}
 
 		// DynamicFeeTx should be rejected if TxHashWithType fork is registered but not enabled for current block

txpool/txpool_test.go

@@ -143,9 +143,35 @@ func TestAddTxErrors(t *testing.T) {
 		tx := newTx(defaultAddr, 0, 1)
 		tx.Type = types.StateTx
 
-		assert.ErrorIs(t,
-			pool.addTx(local, signTx(tx)),
-			ErrInvalidTxType,
+		err := pool.addTx(local, signTx(tx))
+
+		assert.ErrorContains(t,
+			err,
+			ErrInvalidTxType.Error(),
+		)
+		assert.ErrorContains(t,
+			err,
+			"state transactions are not expected to be added to the pool",
+		)
+	})
+
+	t.Run("ErrTxTypeNotSupported London hardfork not enabled", func(t *testing.T) {
+		t.Parallel()
+		pool := setupPool()
+		pool.forks.RemoveFork(chain.London)
+
+		tx := newTx(defaultAddr, 0, 1)
+		tx.Type = types.DynamicFeeTx
+
+		err := pool.addTx(local, signTx(tx))
+
+		assert.ErrorContains(t,
+			err,
+			ErrTxTypeNotSupported.Error(),
+		)
+		assert.ErrorContains(t,
+			err,
+			"london hardfork is not enabled",
 		)
 	})