[NOD-909] Add tests for double spends (#694)

* [NOD-909] Add tests for double spends

* [NOD-909] Add prepareAndProcessBlock that gets parent hashes and transactions as argument

* [NOD-909] Use PrepareAndProcessBlockForTest where possible

* [NOD-909] Use more meaningful names

* [NOD-909] Change a comment

* [NOD-909] Fix comment

* [NOD-909] Fix comment

blockdag/common_test.go

@@ -172,28 +172,12 @@ func checkRuleError(gotErr, wantErr error) error {
 	return nil
 }
 
-func prepareAndProcessBlock(t *testing.T, dag *BlockDAG, parents ...*wire.MsgBlock) *wire.MsgBlock {
+func prepareAndProcessBlockByParentMsgBlocks(t *testing.T, dag *BlockDAG, parents ...*wire.MsgBlock) *wire.MsgBlock {
 	parentHashes := make([]*daghash.Hash, len(parents))
 	for i, parent := range parents {
 		parentHashes[i] = parent.BlockHash()
 	}
-	daghash.Sort(parentHashes)
-	block, err := PrepareBlockForTest(dag, parentHashes, nil)
-	if err != nil {
-		t.Fatalf("error in PrepareBlockForTest: %s", err)
-	}
-	utilBlock := util.NewBlock(block)
-	isOrphan, isDelayed, err := dag.ProcessBlock(utilBlock, BFNoPoWCheck)
-	if err != nil {
-		t.Fatalf("unexpected error in ProcessBlock: %s", err)
-	}
-	if isDelayed {
-		t.Fatalf("block is too far in the future")
-	}
-	if isOrphan {
-		t.Fatalf("block was unexpectedly orphan")
-	}
-	return block
+	return PrepareAndProcessBlockForTest(t, dag, parentHashes, nil)
 }
 
 func nodeByMsgBlock(t *testing.T, dag *BlockDAG, block *wire.MsgBlock) *blockNode {

blockdag/dag_test.go

@@ -688,7 +688,7 @@ func TestConfirmations(t *testing.T) {
 	chainBlocks := make([]*wire.MsgBlock, 5)
 	chainBlocks[0] = dag.dagParams.GenesisBlock
 	for i := uint32(1); i < 5; i++ {
-		chainBlocks[i] = prepareAndProcessBlock(t, dag, chainBlocks[i-1])
+		chainBlocks[i] = prepareAndProcessBlockByParentMsgBlocks(t, dag, chainBlocks[i-1])
 	}
 
 	// Make sure that each one of the chain blocks has the expected confirmations number
@@ -707,8 +707,8 @@ func TestConfirmations(t *testing.T) {
 
 	branchingBlocks := make([]*wire.MsgBlock, 2)
 	// Add two branching blocks
-	branchingBlocks[0] = prepareAndProcessBlock(t, dag, chainBlocks[1])
-	branchingBlocks[1] = prepareAndProcessBlock(t, dag, branchingBlocks[0])
+	branchingBlocks[0] = prepareAndProcessBlockByParentMsgBlocks(t, dag, chainBlocks[1])
+	branchingBlocks[1] = prepareAndProcessBlockByParentMsgBlocks(t, dag, branchingBlocks[0])
 
 	// Check that the genesis has a confirmations number == len(chainBlocks)
 	genesisConfirmations, err = dag.blockConfirmations(dag.genesis)
@@ -738,7 +738,7 @@ func TestConfirmations(t *testing.T) {
 	// Generate 100 blocks to force the "main" chain to become red
 	branchingChainTip := branchingBlocks[1]
 	for i := uint32(0); i < 100; i++ {
-		nextBranchingChainTip := prepareAndProcessBlock(t, dag, branchingChainTip)
+		nextBranchingChainTip := prepareAndProcessBlockByParentMsgBlocks(t, dag, branchingChainTip)
 		branchingChainTip = nextBranchingChainTip
 	}
 
@@ -797,7 +797,7 @@ func TestAcceptingBlock(t *testing.T) {
 	chainBlocks := make([]*wire.MsgBlock, numChainBlocks)
 	chainBlocks[0] = dag.dagParams.GenesisBlock
 	for i := uint32(1); i <= numChainBlocks-1; i++ {
-		chainBlocks[i] = prepareAndProcessBlock(t, dag, chainBlocks[i-1])
+		chainBlocks[i] = prepareAndProcessBlockByParentMsgBlocks(t, dag, chainBlocks[i-1])
 	}
 
 	// Make sure that each chain block (including the genesis) is accepted by its child
@@ -825,7 +825,7 @@ func TestAcceptingBlock(t *testing.T) {
 
 	// Generate a chain tip that will be in the anticone of the selected tip and
 	// in dag.virtual.blues.
-	branchingChainTip := prepareAndProcessBlock(t, dag, chainBlocks[len(chainBlocks)-3])
+	branchingChainTip := prepareAndProcessBlockByParentMsgBlocks(t, dag, chainBlocks[len(chainBlocks)-3])
 
 	// Make sure that branchingChainTip is not in the selected parent chain
 	isBranchingChainTipInSelectedParentChain, err := dag.IsInSelectedParentChain(branchingChainTip.BlockHash())
@@ -863,7 +863,7 @@ func TestAcceptingBlock(t *testing.T) {
 	intersectionBlock := chainBlocks[1]
 	sideChainTip := intersectionBlock
 	for i := 0; i < len(chainBlocks)-3; i++ {
-		sideChainTip = prepareAndProcessBlock(t, dag, sideChainTip)
+		sideChainTip = prepareAndProcessBlockByParentMsgBlocks(t, dag, sideChainTip)
 	}
 
 	// Make sure that the accepting block of the parent of the branching block didn't change
@@ -879,7 +879,7 @@ func TestAcceptingBlock(t *testing.T) {
 
 	// Make sure that a block that is found in the red set of the selected tip
 	// doesn't have an accepting block
-	prepareAndProcessBlock(t, dag, sideChainTip, chainBlocks[len(chainBlocks)-1])
+	prepareAndProcessBlockByParentMsgBlocks(t, dag, sideChainTip, chainBlocks[len(chainBlocks)-1])
 
 	sideChainTipAcceptingBlock, err := acceptingBlockByMsgBlock(sideChainTip)
 	if err != nil {
@@ -1117,3 +1117,132 @@ func TestIsDAGCurrentMaxDiff(t *testing.T) {
 		}
 	}
 }
+
+func TestDoubleSpends(t *testing.T) {
+	params := dagconfig.SimnetParams
+	params.BlockCoinbaseMaturity = 0
+	// Create a new database and dag instance to run tests against.
+	dag, teardownFunc, err := DAGSetup("TestDoubleSpends", true, Config{
+		DAGParams: &params,
+	})
+	if err != nil {
+		t.Fatalf("Failed to setup dag instance: %v", err)
+	}
+	defer teardownFunc()
+
+	fundingBlock := PrepareAndProcessBlockForTest(t, dag, []*daghash.Hash{params.GenesisHash}, nil)
+	cbTx := fundingBlock.Transactions[0]
+
+	signatureScript, err := txscript.PayToScriptHashSignatureScript(OpTrueScript, nil)
+	if err != nil {
+		t.Fatalf("Failed to build signature script: %s", err)
+	}
+	txIn := &wire.TxIn{
+		PreviousOutpoint: wire.Outpoint{TxID: *cbTx.TxID(), Index: 0},
+		SignatureScript:  signatureScript,
+		Sequence:         wire.MaxTxInSequenceNum,
+	}
+	txOut := &wire.TxOut{
+		ScriptPubKey: OpTrueScript,
+		Value:        uint64(1),
+	}
+	tx1 := wire.NewNativeMsgTx(wire.TxVersion, []*wire.TxIn{txIn}, []*wire.TxOut{txOut})
+
+	doubleSpendTxOut := &wire.TxOut{
+		ScriptPubKey: OpTrueScript,
+		Value:        uint64(2),
+	}
+	doubleSpendTx1 := wire.NewNativeMsgTx(wire.TxVersion, []*wire.TxIn{txIn}, []*wire.TxOut{doubleSpendTxOut})
+
+	blockWithTx1 := PrepareAndProcessBlockForTest(t, dag, []*daghash.Hash{fundingBlock.BlockHash()}, []*wire.MsgTx{tx1})
+
+	// Check that a block will be rejected if it has a transaction that already exists in its past.
+	anotherBlockWithTx1, err := PrepareBlockForTest(dag, []*daghash.Hash{blockWithTx1.BlockHash()}, nil)
+	if err != nil {
+		t.Fatalf("PrepareBlockForTest: %v", err)
+	}
+
+	// Manually add tx1.
+	anotherBlockWithTx1.Transactions = append(anotherBlockWithTx1.Transactions, tx1)
+	anotherBlockWithTx1UtilTxs := make([]*util.Tx, len(anotherBlockWithTx1.Transactions))
+	for i, tx := range anotherBlockWithTx1.Transactions {
+		anotherBlockWithTx1UtilTxs[i] = util.NewTx(tx)
+	}
+	anotherBlockWithTx1.Header.HashMerkleRoot = BuildHashMerkleTreeStore(anotherBlockWithTx1UtilTxs).Root()
+
+	isOrphan, isDelayed, err := dag.ProcessBlock(util.NewBlock(anotherBlockWithTx1), BFNoPoWCheck)
+	if err == nil {
+		t.Errorf("ProcessBlock expected an error")
+	} else {
+		var ruleErr RuleError
+		if ok := errors.As(err, &ruleErr); ok {
+			if ruleErr.ErrorCode != ErrOverwriteTx {
+				t.Errorf("ProcessBlock expected an %v error code but got %v", ErrOverwriteTx, ruleErr.ErrorCode)
+			}
+		} else {
+			t.Errorf("ProcessBlock expected a blockdag.RuleError but got %v", err)
+		}
+	}
+	if isDelayed {
+		t.Fatalf("ProcessBlock: anotherBlockWithTx1 " +
+			"is too far in the future")
+	}
+	if isOrphan {
+		t.Fatalf("ProcessBlock: anotherBlockWithTx1 got unexpectedly orphaned")
+	}
+
+	// Check that a block will be rejected if it has a transaction that double spends
+	// a transaction from its past.
+	blockWithDoubleSpendForTx1, err := PrepareBlockForTest(dag, []*daghash.Hash{blockWithTx1.BlockHash()}, nil)
+	if err != nil {
+		t.Fatalf("PrepareBlockForTest: %v", err)
+	}
+
+	// Manually add a transaction that double spends the block past.
+	blockWithDoubleSpendForTx1.Transactions = append(blockWithDoubleSpendForTx1.Transactions, doubleSpendTx1)
+	blockWithDoubleSpendForTx1UtilTxs := make([]*util.Tx, len(blockWithDoubleSpendForTx1.Transactions))
+	for i, tx := range blockWithDoubleSpendForTx1.Transactions {
+		blockWithDoubleSpendForTx1UtilTxs[i] = util.NewTx(tx)
+	}
+	blockWithDoubleSpendForTx1.Header.HashMerkleRoot = BuildHashMerkleTreeStore(blockWithDoubleSpendForTx1UtilTxs).Root()
+
+	isOrphan, isDelayed, err = dag.ProcessBlock(util.NewBlock(blockWithDoubleSpendForTx1), BFNoPoWCheck)
+	if err == nil {
+		t.Errorf("ProcessBlock expected an error")
+	} else {
+		var ruleErr RuleError
+		if ok := errors.As(err, &ruleErr); ok {
+			if ruleErr.ErrorCode != ErrMissingTxOut {
+				t.Errorf("ProcessBlock expected an %v error code but got %v", ErrMissingTxOut, ruleErr.ErrorCode)
+			}
+		} else {
+			t.Errorf("ProcessBlock expected a blockdag.RuleError but got %v", err)
+		}
+	}
+	if isDelayed {
+		t.Fatalf("ProcessBlock: blockWithDoubleSpendForTx1 " +
+			"is too far in the future")
+	}
+	if isOrphan {
+		t.Fatalf("ProcessBlock: blockWithDoubleSpendForTx1 got unexpectedly orphaned")
+	}
+
+	blockInAnticoneOfBlockWithTx1, err := PrepareBlockForTest(dag, []*daghash.Hash{fundingBlock.BlockHash()}, []*wire.MsgTx{doubleSpendTx1})
+	if err != nil {
+		t.Fatalf("PrepareBlockForTest: %v", err)
+	}
+
+	// Check that a block will not get rejected if it has a transaction that double spends
+	// a transaction from its anticone.
+	isOrphan, isDelayed, err = dag.ProcessBlock(util.NewBlock(blockInAnticoneOfBlockWithTx1), BFNoPoWCheck)
+	if err != nil {
+		t.Fatalf("ProcessBlock: %v", err)
+	}
+	if isDelayed {
+		t.Fatalf("ProcessBlock: blockInAnticoneOfBlockWithTx1 " +
+			"is too far in the future")
+	}
+	if isOrphan {
+		t.Fatalf("ProcessBlock: blockInAnticoneOfBlockWithTx1 got unexpectedly orphaned")
+	}
+}

blockdag/ghostdag_test.go

@@ -293,14 +293,14 @@ func TestBlueAnticoneSizeErrors(t *testing.T) {
 	// Prepare a block chain with size K beginning with the genesis block
 	currentBlockA := dag.dagParams.GenesisBlock
 	for i := dagconfig.KType(0); i < dag.dagParams.K; i++ {
-		newBlock := prepareAndProcessBlock(t, dag, currentBlockA)
+		newBlock := prepareAndProcessBlockByParentMsgBlocks(t, dag, currentBlockA)
 		currentBlockA = newBlock
 	}
 
 	// Prepare another block chain with size K beginning with the genesis block
 	currentBlockB := dag.dagParams.GenesisBlock
 	for i := dagconfig.KType(0); i < dag.dagParams.K; i++ {
-		newBlock := prepareAndProcessBlock(t, dag, currentBlockB)
+		newBlock := prepareAndProcessBlockByParentMsgBlocks(t, dag, currentBlockB)
 		currentBlockB = newBlock
 	}
 
@@ -332,11 +332,11 @@ func TestGHOSTDAGErrors(t *testing.T) {
 	defer teardownFunc()
 
 	// Add two child blocks to the genesis
-	block1 := prepareAndProcessBlock(t, dag, dag.dagParams.GenesisBlock)
-	block2 := prepareAndProcessBlock(t, dag, dag.dagParams.GenesisBlock)
+	block1 := prepareAndProcessBlockByParentMsgBlocks(t, dag, dag.dagParams.GenesisBlock)
+	block2 := prepareAndProcessBlockByParentMsgBlocks(t, dag, dag.dagParams.GenesisBlock)
 
 	// Add a child block to the previous two blocks
-	block3 := prepareAndProcessBlock(t, dag, block1, block2)
+	block3 := prepareAndProcessBlockByParentMsgBlocks(t, dag, block1, block2)
 
 	// Clear the reachability store
 	dag.reachabilityStore.loaded = map[daghash.Hash]*reachabilityData{}

blockdag/test_utils.go

@@ -15,6 +15,7 @@ import (
 	"sort"
 	"strings"
 	"sync"
+	"testing"
 
 	"github.com/kaspanet/kaspad/util/subnetworkid"
 
@@ -279,6 +280,28 @@ func PrepareBlockForTest(dag *BlockDAG, parentHashes []*daghash.Hash, transactio
 	return block, nil
 }
 
+// PrepareAndProcessBlockForTest prepares a block that points to the given parent
+// hashes and process it.
+func PrepareAndProcessBlockForTest(t *testing.T, dag *BlockDAG, parentHashes []*daghash.Hash, transactions []*wire.MsgTx) *wire.MsgBlock {
+	daghash.Sort(parentHashes)
+	block, err := PrepareBlockForTest(dag, parentHashes, transactions)
+	if err != nil {
+		t.Fatalf("error in PrepareBlockForTest: %s", err)
+	}
+	utilBlock := util.NewBlock(block)
+	isOrphan, isDelayed, err := dag.ProcessBlock(utilBlock, BFNoPoWCheck)
+	if err != nil {
+		t.Fatalf("unexpected error in ProcessBlock: %s", err)
+	}
+	if isDelayed {
+		t.Fatalf("block is too far in the future")
+	}
+	if isOrphan {
+		t.Fatalf("block was unexpectedly orphan")
+	}
+	return block
+}
+
 // generateDeterministicExtraNonceForTest returns a unique deterministic extra nonce for coinbase data, in order to create unique coinbase transactions.
 func generateDeterministicExtraNonceForTest() uint64 {
 	extraNonceForTest++

blockdag/validate_test.go

@@ -570,9 +570,9 @@ func TestValidateParents(t *testing.T) {
 	}
 	defer teardownFunc()
 
-	a := prepareAndProcessBlock(t, dag, dag.dagParams.GenesisBlock)
-	b := prepareAndProcessBlock(t, dag, a)
-	c := prepareAndProcessBlock(t, dag, dag.dagParams.GenesisBlock)
+	a := prepareAndProcessBlockByParentMsgBlocks(t, dag, dag.dagParams.GenesisBlock)
+	b := prepareAndProcessBlockByParentMsgBlocks(t, dag, a)
+	c := prepareAndProcessBlockByParentMsgBlocks(t, dag, dag.dagParams.GenesisBlock)
 
 	aNode := nodeByMsgBlock(t, dag, a)
 	bNode := nodeByMsgBlock(t, dag, b)

mempool/mempool_test.go

@@ -795,6 +795,57 @@ func TestDoubleSpends(t *testing.T) {
 	testPoolMembership(tc, tx2, false, true, false)
 }
 
+func TestDoubleSpendsFromDAG(t *testing.T) {
+	tc, spendableOuts, teardownFunc, err := newPoolHarness(t, &dagconfig.SimnetParams, 2, "TestDoubleSpendsFromDAG")
+	if err != nil {
+		t.Fatalf("unable to create test pool: %v", err)
+	}
+	defer teardownFunc()
+	harness := tc.harness
+
+	tx, err := harness.createTx(spendableOuts[0], uint64(txRelayFeeForTest), 1)
+	if err != nil {
+		t.Fatalf("unable to create transaction: %v", err)
+	}
+
+	dag := harness.txPool.cfg.DAG
+	blockdag.PrepareAndProcessBlockForTest(t, dag, dag.TipHashes(), []*wire.MsgTx{tx.MsgTx()})
+
+	// Check that a transaction that double spends the DAG UTXO set is orphaned.
+	doubleSpendTx, err := harness.createTx(spendableOuts[0], uint64(txRelayFeeForTest), 2)
+	if err != nil {
+		t.Fatalf("unable to create transaction: %v", err)
+	}
+
+	_, err = harness.txPool.ProcessTransaction(doubleSpendTx, true, 0)
+	if err != nil {
+		t.Fatalf("ProcessTransaction: %s", err)
+	}
+	testPoolMembership(tc, doubleSpendTx, true, false, false)
+
+	// If you send a transaction that some of its outputs exist in the DAG UTXO
+	// set, it won't be added to the orphan pool, and will completely get rejected
+	// from the mempool.
+	// This happens because transactions with the same ID as old transactions
+	// are not allowed as long as some of the old transaction outputs exist
+	// in the UTXO.
+	_, err = harness.txPool.ProcessTransaction(tx, true, 0)
+	var ruleErr RuleError
+	if ok := errors.As(err, &ruleErr); ok {
+		var txRuleErr TxRuleError
+		if ok := errors.As(ruleErr.Err, &txRuleErr); ok {
+			if txRuleErr.RejectCode != wire.RejectDuplicate {
+				t.Errorf("ProcessTransaction expected an %v reject code but got %v", wire.RejectDuplicate, txRuleErr.RejectCode)
+			}
+		} else {
+			t.Errorf("ProcessTransaction expected a ruleErr.Err to be a TxRuleError but got %v", err)
+		}
+	} else {
+		t.Errorf("ProcessTransaction expected a RuleError but got %v", err)
+	}
+	testPoolMembership(tc, tx, false, false, false)
+}
+
 //TestFetchTransaction checks that FetchTransaction
 //returns only transaction from the main pool and not from the orphan pool
 func TestFetchTransaction(t *testing.T) {