debug_traceCall support

[rajivpo]

Component

Anvil

Describe the feature you would like

debug_traceCall is useful for getting a structured execution trace of eth_call, specifically when it comes to tx simulation. Unique challenges include the ability to enable users to leverage custom tracers written in js and state/block overrides, the latter of which is not present in debug_traceTransaction.

Additional context

I'm currently using a custom JS tracer, mostly to format data prior to a response as opposed to doing fancy stuff across multiple opcodes, but not leveraging state/block overrides.

Not sure how many others would benefit from this feature. hardhat does not yet support debug_traceCall either, but does have support for debug_traceTransaction. I'm aware of #1737 but figured I'd put this out there as well.

If this isn't prioritized, an alternative could be to run geth in clique mode with a custom genesis.json and then execute traces accordingly (h/t @tynes for the idea)

[sambacha]

second this

[aditya520]

Would love to have this!

[samhatem]

would love this as well

[nathanhleung]

Agreed, this would be a great feature to have.

[antazoey]

Yes, I really could use this!

[Billy1900]

One more requirement, I got the trace like this:

{
    "depth": 1,
    "gas": 29978936,
    "gasCost": 3,
    "op": "PUSH1",
    "pc": 0,
    "stack": []
},

however, when I use debug_traceTransaction, I got

{
    "depth": 0,
    "error": "",
    "gas": 39469,
    "gasCost": 3,
    "memory": [],
    "op": "PUSH1",
    "pc": 0,
    "stack": [],
    "storage": {}
},

can we add storage and memory part?

[antazoey]

can we add storage and memory part?

I get storage and memory when I request like this:

"debug_traceTransaction", [txn_hash, {"stepsTracing": True, "enableMemory": True}]

Edit: Also, I am running my Anvil node with the --steps-tracing flag

[antazoey]

Wait, didn't #3990 resolve this issue?

[Evalir]

pretty sure it did haha! thanks for flagging @antazoey — closing

[Billy1900]

can we add storage and memory part?

I get storage and memory when I request like this:

"debug_traceTransaction", [txn_hash, {"stepsTracing": True, "enableMemory": True}]

Edit: Also, I am running my Anvil node with the --steps-tracing flag

I am trying to trace a transaction which is not committed so I only want to use debug_traceCall, can I get the same data like via debug_traceTransaction?