cmd/evm: add parent uncle hash to difficulty calculation

ethereum · Aug 8, 2021 · 1b4bac6 · 1b4bac6
1 parent 8c5e89c
commit 1b4bac6
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Showing 6 changed files with 55 additions and 12 deletions.
diff --git a/cmd/evm/internal/t8ntool/execution.go b/cmd/evm/internal/t8ntool/execution.go
@@ -74,6 +74,7 @@ type stEnv struct {
 	BlockHashes      map[math.HexOrDecimal64]common.Hash `json:"blockHashes,omitempty"`
 	Ommers           []ommer                             `json:"ommers,omitempty"`
 	BaseFee          *big.Int                            `json:"currentBaseFee,omitempty"`
+	ParentUncleHash  common.Hash                         `json:"parentUncleHash"`
 }
 
 type stEnvMarshaling struct {
@@ -286,10 +287,15 @@ func rlpHash(x interface{}) (h common.Hash) {
 // the caller does not provide an explicit difficulty, but instead provides only
 // parent timestamp + difficulty.
 // Note: this method only works for ethash engine.
-func calcDifficulty(config *params.ChainConfig, number, currentTime, parentTime uint64, parentDifficulty *big.Int) *big.Int {
+func calcDifficulty(config *params.ChainConfig, number, currentTime, parentTime uint64,
+	parentDifficulty *big.Int, parentUncleHash common.Hash) *big.Int {
+	uncleHash := parentUncleHash
+	if uncleHash == (common.Hash{}) {
+		uncleHash = types.EmptyUncleHash
+	}
 	parent := &types.Header{
 		ParentHash: common.Hash{},
-		UncleHash:  types.EmptyUncleHash,
+		UncleHash:  uncleHash,
 		Difficulty: parentDifficulty,
 		Number:     new(big.Int).SetUint64(number - 1),
 		Time:       parentTime,

diff --git a/cmd/evm/internal/t8ntool/gen_stenv.go b/cmd/evm/internal/t8ntool/gen_stenv.go
diff --git a/cmd/evm/internal/t8ntool/transition.go b/cmd/evm/internal/t8ntool/transition.go
@@ -262,7 +262,8 @@ func Main(ctx *cli.Context) error {
 		case env.Timestamp == 0:
 			return NewError(ErrorVMConfig, errors.New("currentDifficulty cannot be calculated if time is set to 0"))
 		}
-		prestate.Env.Difficulty = calcDifficulty(chainConfig, env.Number, env.Timestamp, env.ParentTimestamp, env.ParentDifficulty)
+		prestate.Env.Difficulty = calcDifficulty(chainConfig, env.Number, env.Timestamp,
+			env.ParentTimestamp, env.ParentDifficulty, env.ParentUncleHash)
 	}
 	// Run the test and aggregate the result
 	s, result, err := prestate.Apply(vmConfig, chainConfig, txs, ctx.Int64(RewardFlag.Name), getTracer)

diff --git a/cmd/evm/testdata/14/env.json b/cmd/evm/testdata/14/env.json
@@ -1,8 +1,9 @@
 {
   "currentCoinbase": "0xc94f5374fce5edbc8e2a8697c15331677e6ebf0b",
   "currentGasLimit": "0x750a163df65e8a",
-  "currentNumber": "12301230",
-  "currentTimestamp": "10000",
-  "parentTimestamp" : "999",
-  "parentDifficulty" : "0x2000"
+  "currentBaseFee": "0x500",
+  "currentNumber": "12800000",
+  "currentTimestamp": "10015",
+  "parentTimestamp" : "99999",
+  "parentDifficulty" : "0x2000000000000"
 }
diff --git a/cmd/evm/testdata/14/env.uncles.json b/cmd/evm/testdata/14/env.uncles.json
@@ -0,0 +1,10 @@
+{
+  "currentCoinbase": "0xc94f5374fce5edbc8e2a8697c15331677e6ebf0b",
+  "currentGasLimit": "0x750a163df65e8a",
+  "currentBaseFee": "0x500",
+  "currentNumber": "12800000",
+  "currentTimestamp": "10035",
+  "parentTimestamp" : "99999",
+  "parentDifficulty" : "0x2000000000000",
+  "parentUncleHash" : "0x000000000000000000000000000000000000000000000000000000000000beef"
+}
diff --git a/cmd/evm/testdata/14/readme.md b/cmd/evm/testdata/14/readme.md
@@ -2,11 +2,12 @@
 
 This test shows how the `evm t8n` can be used to calculate the (ethash) difficulty, if none is provided by the caller. 
 
+Calculating it (with an empty set of txs) using `London` rules (and no provided unclehash for the parent block):
 ```
-./evm t8n --input.alloc=./testdata/14/alloc.json --input.txs=./testdata/14/txs.json --input.env=./testdata/14/env.json --output.result=stdout
-INFO [08-08|16:53:45.535] Trie dumping started                     root=6f0588..7f4bdc
-INFO [08-08|16:53:45.535] Trie dumping complete                    accounts=2 elapsed="75.275µs"
-INFO [08-08|16:53:45.535] Wrote file                               file=alloc.json
+[user@work evm]$ ./evm t8n --input.alloc=./testdata/14/alloc.json --input.txs=./testdata/14/txs.json --input.env=./testdata/14/env.json --output.result=stdout --state.fork=London
+INFO [08-08|17:35:46.876] Trie dumping started                     root=6f0588..7f4bdc
+INFO [08-08|17:35:46.876] Trie dumping complete                    accounts=2 elapsed="89.313µs"
+INFO [08-08|17:35:46.877] Wrote file                               file=alloc.json
 {
  "result": {
   "stateRoot": "0x6f058887ca01549716789c380ede95aecc510e6d1fdc4dbf67d053c7c07f4bdc",
@@ -15,7 +16,25 @@ INFO [08-08|16:53:45.535] Wrote file                               file=alloc.js
   "logsHash": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
   "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
   "receipts": [],
-  "currentDifficulty": 2361183241434822737920
+  "currentDifficulty": 3311729559732224
+ }
+}
+```
+Same thing, but this time providing a non-empty (and non-`emptyKeccak`) unclehash, which leads to a slightly different result:
+```
+[user@work evm]$ ./evm t8n --input.alloc=./testdata/14/alloc.json --input.txs=./testdata/14/txs.json --input.env=./testdata/14/env.uncles.json --output.result=stdout --state.fork=London
+INFO [08-08|17:35:49.232] Trie dumping started                     root=6f0588..7f4bdc
+INFO [08-08|17:35:49.232] Trie dumping complete                    accounts=2 elapsed="83.069µs"
+INFO [08-08|17:35:49.233] Wrote file                               file=alloc.json
+{
+ "result": {
+  "stateRoot": "0x6f058887ca01549716789c380ede95aecc510e6d1fdc4dbf67d053c7c07f4bdc",
+  "txRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+  "receiptRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+  "logsHash": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
+  "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+  "receipts": [],
+  "currentDifficulty": 3311179803918336
  }
 }
 ```