pass the forensics Id at root level (#107)

consensus/XDPoS/engines/engine_v2/forensics.go

@@ -166,7 +166,6 @@ func (f *Forensics) SendForensicProof(chain consensus.ChainReader, engine *XDPoS
 	}
 
 	content, err := json.Marshal(&types.ForensicsContent{
-		Id:                   generateForensicsId(ancestorHash.Hex(), &lowerRoundQC, &higherRoundQC),
 		DivergingBlockHash:   ancestorHash.Hex(),
 		AcrossEpoch:          accrossEpoches,
 		DivergingBlockNumber: ancestorBlock.Number.Uint64(),
@@ -188,6 +187,7 @@ func (f *Forensics) SendForensicProof(chain consensus.ChainReader, engine *XDPoS
 	}
 
 	forensicsProof := &types.ForensicProof{
+		Id:            generateForensicsId(ancestorHash.Hex(), &lowerRoundQC, &higherRoundQC),
 		ForensicsType: "QC",
 		Content:       string(content),
 	}
@@ -325,8 +325,8 @@ func (f *Forensics) FindAncestorBlockHash(chain consensus.ChainReader, firstBloc
 	lowerBlockNumHash := firstBlockInfo.Hash
 	higherBlockNumberHash := secondBlockInfo.Hash
 
-	var ancestorToLowerBlockNumHashPath []string
+	var lowerBlockNumToAncestorHashPath []string
-	var ancestorToHigherBlockNumHashPath []string
+	var higherBlockToAncestorNumHashPath []string
 	orderSwapped := false
 
 	blockNumberDifference := big.NewInt(0).Sub(secondBlockInfo.Number, firstBlockInfo.Number).Int64()
@@ -336,17 +336,17 @@ func (f *Forensics) FindAncestorBlockHash(chain consensus.ChainReader, firstBloc
 		blockNumberDifference = -blockNumberDifference // and make it positive
 		orderSwapped = true
 	}
-	ancestorToLowerBlockNumHashPath = append(ancestorToLowerBlockNumHashPath, lowerBlockNumHash.Hex())
+	lowerBlockNumToAncestorHashPath = append(lowerBlockNumToAncestorHashPath, lowerBlockNumHash.Hex())
-	ancestorToHigherBlockNumHashPath = append(ancestorToHigherBlockNumHashPath, higherBlockNumberHash.Hex())
+	higherBlockToAncestorNumHashPath = append(higherBlockToAncestorNumHashPath, higherBlockNumberHash.Hex())
 
 	// First, make their block number the same to start with
 	for i := 0; i < int(blockNumberDifference); i++ {
 		ph := chain.GetHeaderByHash(higherBlockNumberHash)
 		if ph == nil {
-			return common.Hash{}, ancestorToLowerBlockNumHashPath, ancestorToHigherBlockNumHashPath, fmt.Errorf("unable to find parent block of hash %v", higherBlockNumberHash)
+			return common.Hash{}, lowerBlockNumToAncestorHashPath, higherBlockToAncestorNumHashPath, fmt.Errorf("unable to find parent block of hash %v", higherBlockNumberHash)
 		}
 		higherBlockNumberHash = ph.ParentHash
-		ancestorToHigherBlockNumHashPath = append(ancestorToHigherBlockNumHashPath, ph.ParentHash.Hex())
+		higherBlockToAncestorNumHashPath = append(higherBlockToAncestorNumHashPath, ph.ParentHash.Hex())
 	}
 
 	// Now, they are on the same starting line, we try find the common ancestor
@@ -354,9 +354,13 @@ func (f *Forensics) FindAncestorBlockHash(chain consensus.ChainReader, firstBloc
 		lowerBlockNumHash = chain.GetHeaderByHash(lowerBlockNumHash).ParentHash
 		higherBlockNumberHash = chain.GetHeaderByHash(higherBlockNumberHash).ParentHash
 		// Append the path
-		ancestorToLowerBlockNumHashPath = append(ancestorToLowerBlockNumHashPath, lowerBlockNumHash.Hex())
+		lowerBlockNumToAncestorHashPath = append(lowerBlockNumToAncestorHashPath, lowerBlockNumHash.Hex())
-		ancestorToHigherBlockNumHashPath = append(ancestorToHigherBlockNumHashPath, higherBlockNumberHash.Hex())
+		higherBlockToAncestorNumHashPath = append(higherBlockToAncestorNumHashPath, higherBlockNumberHash.Hex())
 	}
+
+	// Reverse the list order as it's from ancestor to X block path.
+	ancestorToLowerBlockNumHashPath := reverse(lowerBlockNumToAncestorHashPath)
+	ancestorToHigherBlockNumHashPath := reverse(higherBlockToAncestorNumHashPath)
 	// Swap back the order. We must return in the order that matches what we acceptted in the parameter of firstBlock & secondBlock
 	if orderSwapped {
 		return lowerBlockNumHash, ancestorToHigherBlockNumHashPath, ancestorToLowerBlockNumHashPath, nil
@@ -368,3 +372,11 @@ func generateForensicsId(divergingHash string, qc1 *types.QuorumCert, qc2 *types
 	keysList := []string{divergingHash, qc1.ProposedBlockInfo.Hash.Hex(), qc2.ProposedBlockInfo.Hash.Hex()}
 	return strings.Join(keysList[:], ":")
 }
+
+func reverse(ss []string) []string {
+	last := len(ss) - 1
+	for i := 0; i < len(ss)/2; i++ {
+		ss[i], ss[last-i] = ss[last-i], ss[i]
+	}
+	return ss
+}

consensus/tests/engine_v2_tests/forensics_test.go

@@ -295,7 +295,7 @@ func TestForensicsAcrossEpoch(t *testing.T) {
 			json.Unmarshal([]byte(forensics.ForensicsProof.Content), &content)
 
 			idToCompare := content.DivergingBlockHash + ":" + content.SmallerRoundInfo.QuorumCert.ProposedBlockInfo.Hash.Hex() + ":" + content.LargerRoundInfo.QuorumCert.ProposedBlockInfo.Hash.Hex()
-			assert.Equal(t, idToCompare, content.Id)
+			assert.Equal(t, idToCompare, forensics.ForensicsProof.Id)
 			assert.True(t, content.AcrossEpoch)
 			assert.Equal(t, types.Round(900), content.SmallerRoundInfo.QuorumCert.ProposedBlockInfo.Round)
 			assert.Equal(t, uint64(1800), content.SmallerRoundInfo.QuorumCert.ProposedBlockInfo.Number.Uint64())

core/types/forensics.go

@@ -7,7 +7,6 @@ type ForensicsInfo struct {
 }
 
 type ForensicsContent struct {
-	Id                   string         `json:"id"`
 	DivergingBlockNumber uint64         `json:"divergingBlockNumber"`
 	DivergingBlockHash   string         `json:"divergingBlockHash"`
 	AcrossEpoch          bool           `json:"acrossEpoch"`
@@ -16,6 +15,7 @@ type ForensicsContent struct {
 }
 
 type ForensicProof struct {
+	Id            string `json:"id"`
 	ForensicsType string `json:"forensicsType"` // QC or VOTE
 	Content       string `json:"content"`       // Json string of the forensics data
 }