core, graphql, internal: expose effectiveGasPrice in receipts

graphql/graphql.go

@@ -236,6 +236,21 @@ func (t *Transaction) GasPrice(ctx context.Context) (hexutil.Big, error) {
 	}
 }
 
+func (t *Transaction) EffectiveGasPrice(ctx context.Context) (*hexutil.Big, error) {
+	tx, err := t.resolve(ctx)
+	if err != nil || tx == nil {
+		return nil, err
+	}
+	header, err := t.block.resolveHeader(ctx)
+	if err != nil || header == nil {
+		return nil, err
+	}
+	if header.BaseFee == nil {
+		return (*hexutil.Big)(tx.GasPrice()), nil
+	}
+	return (*hexutil.Big)(math.BigMin(new(big.Int).Add(tx.GasTipCap(), header.BaseFee), tx.GasFeeCap())), nil
+}
+
 func (t *Transaction) MaxFeePerGas(ctx context.Context) (*hexutil.Big, error) {
 	tx, err := t.resolve(ctx)
 	if err != nil || tx == nil {

graphql/schema.go

@@ -118,6 +118,13 @@ const schema string = `
         # this transaction. If the transaction has not yet been mined, this field
         # will be null.
         cumulativeGasUsed: Long
+        # EffectiveGasPrice is actual value per gas deducted from the sender's
+        # account. Before EIP-1559, this is equal to the transaction's gas price.
+        # After EIP-1559, it is baseFeePerGas + min(maxFeePerGas - baseFeePerGas,
+        # maxPriorityFeePerGas). Legacy transactions and EIP-2930 transactions are
+        # coerced into the EIP-1559 format by setting both maxFeePerGas and
+        # maxPriorityFeePerGas as the transaction's gas price.
+        effectiveGasPrice: BigInt
         # CreatedContract is the account that was created by a contract creation
         # transaction. If the transaction was not a contract creation transaction,
         # or it has not yet been mined, this field will be null.