Utilize BalanceChangeReason in tracing #375
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…e with balanceChangeReason
eth/tracers/native/call.go
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| @@ -50,6 +50,7 @@ type callFrame struct { | |||
| // Arbitrum: we add these here due to the tracer returning the top frame | |||
| BeforeEVMTransfers *[]arbitrumTransfer `json:"beforeEVMTransfers,omitempty"` | |||
| AfterEVMTransfers *[]arbitrumTransfer `json:"afterEVMTransfers,omitempty"` | |||
| BalanceChanges *[]balanceChange `json:"balanceChanges,omitempty"` | |||
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what's the motivation for adding these here?
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I added balanceChanges right after beforeEVMTransfers and afterEVMTransfers to show all the balance changes step-by-step that happened when a tx gets executed, leading to a trace something like
{
"beforeEVMTransfers": [
{
"purpose": "purchase of gas for execution of a transaction",
"from": "0x26E554a8acF9003b83495c7f45F06edCB803d4e3",
"to": null,
"value": "0x0"
}
],
"afterEVMTransfers": [
{
"purpose": "refund for unused gas at the end of execution",
"from": null,
"to": "0x26E554a8acF9003b83495c7f45F06edCB803d4e3",
"value": "0x0"
},
{
"purpose": "fee collection by network fee account",
"from": null,
"to": "0x0000000000000000000000000000000000000000",
"value": "0x6260d337500"
},
{
"purpose": "fee collection for L1 posting",
"from": null,
"to": "0xa4B00000000000000000000000000000000000F6",
"value": "0x68e6df69800"
}
],
"balanceChanges": [
{
"addr": "0x26E554a8acF9003b83495c7f45F06edCB803d4e3",
"prev": "0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff7",
"new": "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffc46535f7",
"reason": "balance decrease due to transfer via a call"
},
{
"addr": "0x0000000000000000000000000000000000000064",
"prev": "0x0",
"new": "0x3b9aca00",
"reason": "balance increase due to transfer via a call"
},
{
"addr": "0x0000000000000000000000000000000000000064",
"prev": "0x3b9aca00",
"new": "0x0",
"reason": "balance decrease due to withdrawal to L1"
},
{
"addr": "0x0000000000000000000000000000000000000000",
"prev": "0x0",
"new": "0x6260d337500",
"reason": "balance increase due to fee collection by network fee account"
},
{
"addr": "0xa4B00000000000000000000000000000000000F6",
"prev": "0x0",
"new": "0x68e6df69800",
"reason": "balance increase due to fee collection for L1 posting"
}
],
...
}
Let me know if I got it wrong
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I don't think it's "wrong", but we should try to only change geth code when there is a strong customer-affecting motivation to do so, and I don't think there is one here.
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Oh got it! I've reverted the changes
core/tracing/hooks.go
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| ) | ||
|
|
||
| func (b BalanceChangeReason) String(prev, new *big.Int) string { |
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What's the motivation for the new strings? Are they formatted after anything standard?
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The thing is geth itself doesn't use BalanceChangeReason type for anything meaningful (as of 1.14.0) i.e in any of the tracing code, but gives us the freedom to decide how and where we use it.
They aren't formatted after anything standard but gives the reason for the balance change itself, which I thought we could use in tracing, let me know if I got it wrong.
For example geth's current master uses BalanceChangeReason this way https://github.com/ethereum/go-ethereum/blob/6d3d252a5ece0687dcaaf197e0bfc03466161ff1/eth/tracers/live/supply.go#L191-L208
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earlier in the purpose field of beforeEVMTransfers and afterEVMTransfers we had single word strings like feeCollection, tip etc.. but now we could have a more descriptive reasons with the String() impl like in the above comment
...
...{ "beforeEVMTransfers": [ { "purpose": "purchase of gas for execution of a transaction", "from": "0x26E554a8acF9003b83495c7f45F06edCB803d4e3", "to": null, "value": "0x0" } ], "afterEVMTransfers": [ { "purpose": "refund for unused gas at the end of execution", "from": null, "to": "0x26E554a8acF9003b83495c7f45F06edCB803d4e3", "value": "0x0" },
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I am not sure, but I guess someone is already parsing the exiting short srings.
If they are - this change would hurt them, and I rather avoid it.
We could still have a "String" function but have it return the old string to avoid compatibility errors.
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Changed the String() to be backwards compatible
This PR enables usage of
BalanceChangeReasontype in tracing, such as inCaptureArbitrumTransferand also to trace balance changes themself usingjsTracer.We replace the string in
purposefield of bothbeforeEVMTransfersandafterEVMTransferswith the reasoning derived fromtracing.BalanceChangeReason, the strings themself are kept the same to maintain backwards compatibility.We added following balanceChangeReasons-
Corresponding nitro PR- OffchainLabs/nitro#2789
Part of NIT-2943