From 8e95477065dc765f3be83c71baeeb4e508330ee8 Mon Sep 17 00:00:00 2001
From: Nate Maninger <me@n8m.us>
Date: Fri, 23 Aug 2024 10:59:02 -0700
Subject: [PATCH] fix panic when mining v2 transactions at the allow height

---
 miner.go      | 19 ++++++-----
 miner_test.go | 92 ++++++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 98 insertions(+), 13 deletions(-)

diff --git a/miner.go b/miner.go
index 91395ae..85ad705 100644
--- a/miner.go
+++ b/miner.go
@@ -55,9 +55,10 @@ retry:
 		}},
 	}
 
-	if cs.Index.Height >= cs.Network.HardforkV2.AllowHeight {
+	childHeight := cs.Index.Height + 1
+	if childHeight >= cs.Network.HardforkV2.AllowHeight {
 		b.V2 = &types.V2BlockData{
-			Height: cs.Index.Height + 1,
+			Height: childHeight,
 		}
 	}
 
@@ -69,14 +70,14 @@ retry:
 		b.Transactions = append(b.Transactions, txn)
 		b.MinerPayouts[0].Value = b.MinerPayouts[0].Value.Add(txn.TotalFees())
 	}
-	for _, txn := range v2Txns {
-		if weight += cs.V2TransactionWeight(txn); weight > cs.MaxBlockWeight() {
-			break
-		}
-		b.V2.Transactions = append(b.V2.Transactions, txn)
-		b.MinerPayouts[0].Value = b.MinerPayouts[0].Value.Add(txn.MinerFee)
-	}
 	if b.V2 != nil {
+		for _, txn := range v2Txns {
+			if weight += cs.V2TransactionWeight(txn); weight > cs.MaxBlockWeight() {
+				break
+			}
+			b.V2.Transactions = append(b.V2.Transactions, txn)
+			b.MinerPayouts[0].Value = b.MinerPayouts[0].Value.Add(txn.MinerFee)
+		}
 		b.V2.Commitment = cs.Commitment(cs.TransactionsCommitment(b.Transactions, b.V2Transactions()), addr)
 	}
 	found := FindBlockNonce(cs, &b, timeout)
diff --git a/miner_test.go b/miner_test.go
index 2bb4c73..8f5b47c 100644
--- a/miner_test.go
+++ b/miner_test.go
@@ -1,16 +1,17 @@
-package coreutils
+package coreutils_test
 
 import (
 	"testing"
 	"time"
 
 	"go.sia.tech/core/types"
+	"go.sia.tech/coreutils"
 	"go.sia.tech/coreutils/chain"
+	"go.sia.tech/coreutils/testutil"
 )
 
 func TestMiner(t *testing.T) {
-	n, genesisBlock := chain.TestnetZen()
-	n.InitialTarget = types.BlockID{0xFF}
+	n, genesisBlock := testutil.Network()
 
 	sk := types.GeneratePrivateKey()
 	genesisBlock.Transactions = []types.Transaction{{
@@ -59,7 +60,7 @@ func TestMiner(t *testing.T) {
 	}
 
 	// assert the minerpayout includes the txn fee
-	b, found := MineBlock(cm, types.VoidAddress, time.Second)
+	b, found := coreutils.MineBlock(cm, types.VoidAddress, time.Second)
 	if !found {
 		t.Fatal("PoW failed")
 	} else if len(b.MinerPayouts) != 1 {
@@ -68,3 +69,86 @@ func TestMiner(t *testing.T) {
 		t.Fatal("unexpected miner payout", b.MinerPayouts[0].Value.ExactString())
 	}
 }
+
+func TestV2MineBlocks(t *testing.T) {
+	n, genesisBlock := testutil.V2Network()
+	n.HardforkV2.AllowHeight = 5
+	n.HardforkV2.RequireHeight = 10
+	n.InitialTarget = types.BlockID{0xFF}
+
+	genesisBlock.Transactions = []types.Transaction{{
+		SiacoinOutputs: []types.SiacoinOutput{
+			{
+				Address: types.AnyoneCanSpend().Address(),
+				Value:   types.Siacoins(10),
+			},
+		},
+	}}
+
+	store, tipState, err := chain.NewDBStore(chain.NewMemDB(), n, genesisBlock)
+	if err != nil {
+		t.Fatal(err)
+	}
+	cm := chain.NewManager(store, tipState)
+
+	mineBlocks := func(t *testing.T, n int) {
+		for ; n > 0; n-- {
+			b, ok := coreutils.MineBlock(cm, types.VoidAddress, time.Second)
+			if !ok {
+				t.Fatal("failed to mine block")
+			} else if err := cm.AddBlocks([]types.Block{b}); err != nil {
+				t.Fatal(err)
+			}
+		}
+	}
+
+	// mine until just before the allow height
+	mineBlocks(t, 4)
+
+	elements := make(map[types.Hash256]types.SiacoinElement)
+	_, applied, err := cm.UpdatesSince(types.ChainIndex{}, 500)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, cau := range applied {
+		cau.ForEachSiacoinElement(func(sce types.SiacoinElement, created, spent bool) {
+			switch {
+			case created && spent:
+				return
+			case sce.SiacoinOutput.Address != types.AnyoneCanSpend().Address():
+				return
+			case created:
+				elements[sce.ID] = sce
+			case spent:
+				delete(elements, sce.ID)
+			}
+		})
+
+		for k, v := range elements {
+			cau.UpdateElementProof(&v.StateElement)
+			elements[k] = v
+		}
+	}
+
+	var se types.SiacoinElement
+	for _, v := range elements {
+		se = v
+		break
+	}
+
+	txn := types.V2Transaction{
+		MinerFee: se.SiacoinOutput.Value,
+		SiacoinInputs: []types.V2SiacoinInput{{
+			Parent:          se,
+			SatisfiedPolicy: types.SatisfiedPolicy{Policy: types.AnyoneCanSpend()},
+		}},
+	}
+
+	// add the transaction to the pool
+	_, err = cm.AddV2PoolTransactions(cm.Tip(), []types.V2Transaction{txn})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	mineBlocks(t, 1)
+}