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cmd/evm: add difficulty calculation to t8n tool (ethereum#23353)
This PR adds functionality to the evm t8n to calculate ethash difficulty. If the caller does not provide a currentDifficulty, but instead provides the parentTimestamp (well, semi-optional, will default to 0 if not given), and parentDifficulty, we can calculate it for him. The caller can also provide a parentUncleHash. In most, but not all cases, the parent uncle hash also affects the formula. If no such hash is provided (or, if the empty all-zero hash is provided), it's assumed that there were no uncles.
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-40
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8 files changed

+172
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lines changed

‎cmd/evm/internal/t8ntool/execution.go

+49-21
Original file line numberDiff line numberDiff line change
@@ -23,6 +23,7 @@ import (
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2424
"github.com/ethereum/go-ethereum/common"
2525
"github.com/ethereum/go-ethereum/common/math"
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"github.com/ethereum/go-ethereum/consensus/ethash"
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"github.com/ethereum/go-ethereum/consensus/misc"
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"github.com/ethereum/go-ethereum/core"
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"github.com/ethereum/go-ethereum/core/rawdb"
@@ -46,13 +47,14 @@ type Prestate struct {
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// ExecutionResult contains the execution status after running a state test, any
4748
// error that might have occurred and a dump of the final state if requested.
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type ExecutionResult struct {
49-
StateRoot common.Hash `json:"stateRoot"`
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TxRoot common.Hash `json:"txRoot"`
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ReceiptRoot common.Hash `json:"receiptRoot"`
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LogsHash common.Hash `json:"logsHash"`
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Bloom types.Bloom `json:"logsBloom" gencodec:"required"`
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Receipts types.Receipts `json:"receipts"`
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Rejected []*rejectedTx `json:"rejected,omitempty"`
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StateRoot common.Hash `json:"stateRoot"`
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TxRoot common.Hash `json:"txRoot"`
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ReceiptRoot common.Hash `json:"receiptRoot"`
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LogsHash common.Hash `json:"logsHash"`
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Bloom types.Bloom `json:"logsBloom" gencodec:"required"`
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Receipts types.Receipts `json:"receipts"`
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Rejected []*rejectedTx `json:"rejected,omitempty"`
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Difficulty *math.HexOrDecimal256 `json:"currentDifficulty" gencodec:"required"`
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}
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5860
type ommer struct {
@@ -62,23 +64,28 @@ type ommer struct {
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//go:generate gencodec -type stEnv -field-override stEnvMarshaling -out gen_stenv.go
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type stEnv struct {
65-
Coinbase common.Address `json:"currentCoinbase" gencodec:"required"`
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Difficulty *big.Int `json:"currentDifficulty" gencodec:"required"`
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GasLimit uint64 `json:"currentGasLimit" gencodec:"required"`
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Number uint64 `json:"currentNumber" gencodec:"required"`
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Timestamp uint64 `json:"currentTimestamp" gencodec:"required"`
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BlockHashes map[math.HexOrDecimal64]common.Hash `json:"blockHashes,omitempty"`
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Ommers []ommer `json:"ommers,omitempty"`
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BaseFee *big.Int `json:"currentBaseFee,omitempty"`
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Coinbase common.Address `json:"currentCoinbase" gencodec:"required"`
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Difficulty *big.Int `json:"currentDifficulty"`
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ParentDifficulty *big.Int `json:"parentDifficulty"`
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GasLimit uint64 `json:"currentGasLimit" gencodec:"required"`
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Number uint64 `json:"currentNumber" gencodec:"required"`
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Timestamp uint64 `json:"currentTimestamp" gencodec:"required"`
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ParentTimestamp uint64 `json:"parentTimestamp,omitempty"`
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BlockHashes map[math.HexOrDecimal64]common.Hash `json:"blockHashes,omitempty"`
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Ommers []ommer `json:"ommers,omitempty"`
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BaseFee *big.Int `json:"currentBaseFee,omitempty"`
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ParentUncleHash common.Hash `json:"parentUncleHash"`
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}
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type stEnvMarshaling struct {
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Coinbase common.UnprefixedAddress
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Difficulty *math.HexOrDecimal256
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GasLimit math.HexOrDecimal64
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Number math.HexOrDecimal64
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Timestamp math.HexOrDecimal64
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BaseFee *math.HexOrDecimal256
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Coinbase common.UnprefixedAddress
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Difficulty *math.HexOrDecimal256
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ParentDifficulty *math.HexOrDecimal256
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GasLimit math.HexOrDecimal64
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Number math.HexOrDecimal64
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Timestamp math.HexOrDecimal64
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ParentTimestamp math.HexOrDecimal64
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BaseFee *math.HexOrDecimal256
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}
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type rejectedTx struct {
@@ -247,6 +254,7 @@ func (pre *Prestate) Apply(vmConfig vm.Config, chainConfig *params.ChainConfig,
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LogsHash: rlpHash(statedb.Logs()),
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Receipts: receipts,
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Rejected: rejectedTxs,
257+
Difficulty: (*math.HexOrDecimal256)(vmContext.Difficulty),
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}
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return statedb, execRs, nil
252260
}
@@ -274,3 +282,23 @@ func rlpHash(x interface{}) (h common.Hash) {
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hw.Sum(h[:0])
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return h
276284
}
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// calcDifficulty is based on ethash.CalcDifficulty. This method is used in case
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// the caller does not provide an explicit difficulty, but instead provides only
288+
// parent timestamp + difficulty.
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// Note: this method only works for ethash engine.
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func calcDifficulty(config *params.ChainConfig, number, currentTime, parentTime uint64,
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parentDifficulty *big.Int, parentUncleHash common.Hash) *big.Int {
292+
uncleHash := parentUncleHash
293+
if uncleHash == (common.Hash{}) {
294+
uncleHash = types.EmptyUncleHash
295+
}
296+
parent := &types.Header{
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ParentHash: common.Hash{},
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UncleHash: uncleHash,
299+
Difficulty: parentDifficulty,
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Number: new(big.Int).SetUint64(number - 1),
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Time: parentTime,
302+
}
303+
return ethash.CalcDifficulty(config, currentTime, parent)
304+
}

‎cmd/evm/internal/t8ntool/gen_stenv.go

+36-19
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‎cmd/evm/internal/t8ntool/transition.go

+14
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@@ -252,6 +252,20 @@ func Main(ctx *cli.Context) error {
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return NewError(ErrorVMConfig, errors.New("EIP-1559 config but missing 'currentBaseFee' in env section"))
253253
}
254254
}
255+
if env := prestate.Env; env.Difficulty == nil {
256+
// If difficulty was not provided by caller, we need to calculate it.
257+
switch {
258+
case env.ParentDifficulty == nil:
259+
return NewError(ErrorVMConfig, errors.New("currentDifficulty was not provided, and cannot be calculated due to missing parentDifficulty"))
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case env.Number == 0:
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return NewError(ErrorVMConfig, errors.New("currentDifficulty needs to be provided for block number 0"))
262+
case env.Timestamp <= env.ParentTimestamp:
263+
return NewError(ErrorVMConfig, fmt.Errorf("currentDifficulty cannot be calculated -- currentTime (%d) needs to be after parent time (%d)",
264+
env.Timestamp, env.ParentTimestamp))
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}
266+
prestate.Env.Difficulty = calcDifficulty(chainConfig, env.Number, env.Timestamp,
267+
env.ParentTimestamp, env.ParentDifficulty, env.ParentUncleHash)
268+
}
255269
// Run the test and aggregate the result
256270
s, result, err := prestate.Apply(vmConfig, chainConfig, txs, ctx.Int64(RewardFlag.Name), getTracer)
257271
if err != nil {

‎cmd/evm/testdata/14/alloc.json

+12
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@@ -0,0 +1,12 @@
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{
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"a94f5374fce5edbc8e2a8697c15331677e6ebf0b": {
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"balance": "0x5ffd4878be161d74",
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"code": "0x",
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"nonce": "0xac",
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"storage": {}
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},
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"0x8a8eafb1cf62bfbeb1741769dae1a9dd47996192":{
9+
"balance": "0xfeedbead",
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"nonce" : "0x00"
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}
12+
}

‎cmd/evm/testdata/14/env.json

+9
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@@ -0,0 +1,9 @@
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{
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"currentCoinbase": "0xc94f5374fce5edbc8e2a8697c15331677e6ebf0b",
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"currentGasLimit": "0x750a163df65e8a",
4+
"currentBaseFee": "0x500",
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"currentNumber": "12800000",
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"currentTimestamp": "10015",
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"parentTimestamp" : "99999",
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"parentDifficulty" : "0x2000000000000"
9+
}

‎cmd/evm/testdata/14/env.uncles.json

+10
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@@ -0,0 +1,10 @@
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{
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"currentCoinbase": "0xc94f5374fce5edbc8e2a8697c15331677e6ebf0b",
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"currentGasLimit": "0x750a163df65e8a",
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"currentBaseFee": "0x500",
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"currentNumber": "12800000",
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"currentTimestamp": "10035",
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"parentTimestamp" : "99999",
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"parentDifficulty" : "0x2000000000000",
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"parentUncleHash" : "0x000000000000000000000000000000000000000000000000000000000000beef"
10+
}

‎cmd/evm/testdata/14/readme.md

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@@ -0,0 +1,41 @@
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## Difficulty calculation
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This test shows how the `evm t8n` can be used to calculate the (ethash) difficulty, if none is provided by the caller.
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5+
Calculating it (with an empty set of txs) using `London` rules (and no provided unclehash for the parent block):
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```
7+
[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
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INFO [08-08|17:35:46.876] Trie dumping started root=6f0588..7f4bdc
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INFO [08-08|17:35:46.876] Trie dumping complete accounts=2 elapsed="89.313µs"
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INFO [08-08|17:35:46.877] Wrote file file=alloc.json
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{
12+
"result": {
13+
"stateRoot": "0x6f058887ca01549716789c380ede95aecc510e6d1fdc4dbf67d053c7c07f4bdc",
14+
"txRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
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"receiptRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
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"logsHash": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
17+
"logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
18+
"receipts": [],
19+
"currentDifficulty": 3311729559732224
20+
}
21+
}
22+
```
23+
Same thing, but this time providing a non-empty (and non-`emptyKeccak`) unclehash, which leads to a slightly different result:
24+
```
25+
[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
26+
INFO [08-08|17:35:49.232] Trie dumping started root=6f0588..7f4bdc
27+
INFO [08-08|17:35:49.232] Trie dumping complete accounts=2 elapsed="83.069µs"
28+
INFO [08-08|17:35:49.233] Wrote file file=alloc.json
29+
{
30+
"result": {
31+
"stateRoot": "0x6f058887ca01549716789c380ede95aecc510e6d1fdc4dbf67d053c7c07f4bdc",
32+
"txRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
33+
"receiptRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
34+
"logsHash": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
35+
"logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
36+
"receipts": [],
37+
"currentDifficulty": 3311179803918336
38+
}
39+
}
40+
```
41+

‎cmd/evm/testdata/14/txs.json

+1
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@@ -0,0 +1 @@
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[]

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