From 84f37d3915cfd254eb27bd25feff535e53a2fc1e Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 12 Mar 2026 16:24:50 +0000
Subject: [PATCH] cmd/pushtx: add tx cost display to catch insufficient funds
 before broadcast

Co-authored-by: drQedwards <213266729+drQedwards@users.noreply.github.com>
---
 cmd/pushtx/main.go      |  8 ++++++++
 cmd/pushtx/main_test.go | 14 ++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/cmd/pushtx/main.go b/cmd/pushtx/main.go
index e4a8ff226a..bc0953c615 100644
--- a/cmd/pushtx/main.go
+++ b/cmd/pushtx/main.go
@@ -156,9 +156,17 @@ func printTxSummary(tx *types.Transaction) {
 	fmt.Println("  Value:    ", formatWei(tx.Value()))
 	fmt.Println("  Gas limit:", tx.Gas())
 	fmt.Println("  Gas price:", formatGwei(tx.GasPrice()))
+	fmt.Println("  Tx cost:  ", formatWei(txCost(tx)))
 	fmt.Println("  Chain ID: ", tx.ChainId())
 }
 
+// txCost returns value + gas * gasPrice, i.e. the total ETH the sender
+// must hold for the transaction to be accepted by the network.
+func txCost(tx *types.Transaction) *big.Int {
+	gasCost := new(big.Int).Mul(new(big.Int).SetUint64(tx.Gas()), tx.GasPrice())
+	return new(big.Int).Add(tx.Value(), gasCost)
+}
+
 // formatWei converts a wei amount to a human-readable string showing
 // both the wei value and the ETH equivalent.
 func formatWei(wei *big.Int) string {
diff --git a/cmd/pushtx/main_test.go b/cmd/pushtx/main_test.go
index 0459602928..f5b6c0eb78 100644
--- a/cmd/pushtx/main_test.go
+++ b/cmd/pushtx/main_test.go
@@ -272,6 +272,20 @@ func TestFormatGwei(t *testing.T) {
 	}
 }
 
+func TestTxCost(t *testing.T) {
+	tx := types.NewTx(&types.LegacyTx{
+		GasPrice: big.NewInt(1_000_000_000), // 1 Gwei
+		Gas:      21055,
+		Value:    new(big.Int).Mul(big.NewInt(10), big.NewInt(1e18)), // 10 ETH
+	})
+	got := txCost(tx)
+	// Expected: 10 ETH + 21055 * 1 Gwei = 10000000000000000000 + 21055000000000 = 10000021055000000000
+	want, _ := new(big.Int).SetString("10000021055000000000", 10)
+	if got.Cmp(want) != 0 {
+		t.Errorf("txCost = %s, want %s", got, want)
+	}
+}
+
 func TestRunEqualsSyntax(t *testing.T) {
 	srv := fakeRPC(t, false)
 	defer srv.Close()