channeldb: add local and remote balance to revocation log

This commit re-adds the LocalBalance and RemoteBalance fields to the
RevocationLog. The channeldb/migration30 is also adjusted so that anyone
who has not yet run the optional migration will not lose these fields if
they run the migration after this commit.

The reason for re-adding these fields is that they are needed if we want
to reconstruct all the info of the lnwallet.BreachRetribution without
having access to the breach spend transaction. In most cases we would
have access to the spend tx since we would see it on-chain at which time
we would want to reconstruct the retribution info. However, for the
watchtower subsystem, we sometimes want to construct the retribution
info withouth having access to the spend transaction.

A user can use the `--no-rev-log-amt-data` flag to opt-out of storing
these amount fields.

channeldb/revocation_log_test.go

@@ -56,10 +56,13 @@ var (
 		0x4, 0x5, 0xfe, 0x0, 0xf, 0x42, 0x40,
 	}
 
+	localBalance  = lnwire.MilliSatoshi(9000)
+	remoteBalance = lnwire.MilliSatoshi(3000)
+
 	testChannelCommit = ChannelCommitment{
 		CommitHeight:  999,
-		LocalBalance:  lnwire.MilliSatoshi(9000),
-		RemoteBalance: lnwire.MilliSatoshi(3000),
+		LocalBalance:  localBalance,
+		RemoteBalance: remoteBalance,
 		CommitFee:     btcutil.Amount(rand.Int63()),
 		FeePerKw:      btcutil.Amount(5000),
 		CommitTx:      channels.TestFundingTx,
@@ -74,13 +77,13 @@ var (
 		}},
 	}
 
-	testRevocationLog = RevocationLog{
+	testRevocationLogNoAmts = RevocationLog{
 		OurOutputIndex:   0,
 		TheirOutputIndex: 1,
 		CommitTxHash:     testChannelCommit.CommitTx.TxHash(),
 		HTLCEntries:      []*HTLCEntry{&testHTLCEntry},
 	}
-	testRevocationLogBytes = []byte{
+	testRevocationLogNoAmtsBytes = []byte{
 		// Body length 42.
 		0x2a,
 		// OurOutputIndex tlv.
@@ -94,6 +97,33 @@ var (
 		0xbd, 0xf7, 0xd3, 0x9b, 0x16, 0x7d, 0x0, 0xff,
 		0xc8, 0x22, 0x51, 0xb1, 0x5b, 0xa0, 0xbf, 0xd,
 	}
+
+	testRevocationLogWithAmts = RevocationLog{
+		OurOutputIndex:   0,
+		TheirOutputIndex: 1,
+		CommitTxHash:     testChannelCommit.CommitTx.TxHash(),
+		HTLCEntries:      []*HTLCEntry{&testHTLCEntry},
+		OurBalance:       &localBalance,
+		TheirBalance:     &remoteBalance,
+	}
+	testRevocationLogWithAmtsBytes = []byte{
+		// Body length 52.
+		0x34,
+		// OurOutputIndex tlv.
+		0x0, 0x2, 0x0, 0x0,
+		// TheirOutputIndex tlv.
+		0x1, 0x2, 0x0, 0x1,
+		// CommitTxHash tlv.
+		0x2, 0x20,
+		0x28, 0x76, 0x2, 0x59, 0x1d, 0x9d, 0x64, 0x86,
+		0x6e, 0x60, 0x29, 0x23, 0x1d, 0x5e, 0xc5, 0xe6,
+		0xbd, 0xf7, 0xd3, 0x9b, 0x16, 0x7d, 0x0, 0xff,
+		0xc8, 0x22, 0x51, 0xb1, 0x5b, 0xa0, 0xbf, 0xd,
+		// OurBalance.
+		0x3, 0x3, 0xfd, 0x23, 0x28,
+		// Remote Balance.
+		0x4, 0x3, 0xfd, 0x0b, 0xb8,
+	}
 )
 
 func TestWriteTLVStream(t *testing.T) {
@@ -208,22 +238,75 @@ func TestSerializeHTLCEntries(t *testing.T) {
 	require.Equal(t, expectedBytes, buf.Bytes())
 }
 
-func TestSerializeRevocationLog(t *testing.T) {
+// TestSerializeAndDeserializeRevLog tests the serialization and deserialization
+// of various forms of the revocation log.
+func TestSerializeAndDeserializeRevLog(t *testing.T) {
 	t.Parallel()
 
-	// Copy the testRevocationLog and testHTLCEntry.
-	rl := testRevocationLog
+	tests := []struct {
+		name        string
+		revLog      RevocationLog
+		revLogBytes []byte
+	}{
+		{
+			name:        "with no amount fields",
+			revLog:      testRevocationLogNoAmts,
+			revLogBytes: testRevocationLogNoAmtsBytes,
+		},
+		{
+			name:        "with amount fields",
+			revLog:      testRevocationLogWithAmts,
+			revLogBytes: testRevocationLogWithAmtsBytes,
+		},
+	}
+
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			testSerializeRevocationLog(
+				t, &test.revLog, test.revLogBytes,
+			)
+
+			testDerializeRevocationLog(
+				t, &test.revLog, test.revLogBytes,
+			)
+		})
+	}
+}
+
+func testSerializeRevocationLog(t *testing.T, rl *RevocationLog,
+	revLogBytes []byte) {
+
+	// Copy the testRevocationLogWithAmts and testHTLCEntry.
 	htlc := testHTLCEntry
 	rl.HTLCEntries = []*HTLCEntry{&htlc}
 
 	// Write the tlv stream.
 	buf := bytes.NewBuffer([]byte{})
-	err := serializeRevocationLog(buf, &rl)
+	err := serializeRevocationLog(buf, rl)
 	require.NoError(t, err)
 
 	// Check the expected bytes on the body of the revocation log.
 	bodyIndex := buf.Len() - len(testHTLCEntryBytes)
-	require.Equal(t, testRevocationLogBytes, buf.Bytes()[:bodyIndex])
+	require.Equal(t, revLogBytes, buf.Bytes()[:bodyIndex])
+}
+
+func testDerializeRevocationLog(t *testing.T, revLog *RevocationLog,
+	revLogBytes []byte) {
+
+	// Construct the full bytes.
+	revLogBytes = append(revLogBytes, testHTLCEntryBytes...)
+
+	// Read the tlv stream.
+	buf := bytes.NewBuffer(revLogBytes)
+	rl, err := deserializeRevocationLog(buf)
+	require.NoError(t, err)
+
+	// Check the bytes are read as expected.
+	require.Len(t, rl.HTLCEntries, 1)
+	require.Equal(t, *revLog, rl)
 }
 
 func TestDerializeHTLCEntriesEmptyRHash(t *testing.T) {
@@ -271,23 +354,6 @@ func TestDerializeHTLCEntries(t *testing.T) {
 	require.Equal(t, &entry, htlcs[0])
 }
 
-func TestDerializeRevocationLog(t *testing.T) {
-	t.Parallel()
-
-	// Construct the full bytes.
-	b := testRevocationLogBytes
-	b = append(b, testHTLCEntryBytes...)
-
-	// Read the tlv stream.
-	buf := bytes.NewBuffer(b)
-	rl, err := deserializeRevocationLog(buf)
-	require.NoError(t, err)
-
-	// Check the bytes are read as expected.
-	require.Len(t, rl.HTLCEntries, 1)
-	require.Equal(t, testRevocationLog, rl)
-}
-
 func TestFetchLogBucket(t *testing.T) {
 	t.Parallel()
 
@@ -374,12 +440,22 @@ func TestPutRevocationLog(t *testing.T) {
 	}{
 		{
 			// Test a normal put operation.
-			name:        "successful put",
+			name:        "successful put with amount data",
 			commit:      testChannelCommit,
 			ourIndex:    0,
 			theirIndex:  1,
 			expectedErr: nil,
-			expectedLog: testRevocationLog,
+			expectedLog: testRevocationLogWithAmts,
+		},
+		{
+			// Test a normal put operation.
+			name:        "successful put with no amount data",
+			commit:      testChannelCommit,
+			ourIndex:    0,
+			theirIndex:  1,
+			noAmtData:   true,
+			expectedErr: nil,
+			expectedLog: testRevocationLogNoAmts,
 		},
 		{
 			// Test our index too big.
@@ -410,12 +486,22 @@ func TestPutRevocationLog(t *testing.T) {
 		},
 		{
 			// Test dust htlc is not saved.
-			name:        "dust htlc not saved",
+			name:        "dust htlc not saved with amout data",
 			commit:      testCommitDust,
 			ourIndex:    0,
 			theirIndex:  1,
 			expectedErr: nil,
-			expectedLog: testRevocationLog,
+			expectedLog: testRevocationLogWithAmts,
+		},
+		{
+			// Test dust htlc is not saved.
+			name:        "dust htlc not saved with no amount data",
+			commit:      testCommitDust,
+			ourIndex:    0,
+			theirIndex:  1,
+			noAmtData:   true,
+			expectedErr: nil,
+			expectedLog: testRevocationLogNoAmts,
 		},
 	}