[BUG] estimate_fee_sync always fails with TRANSACTION_FAILED

[Pet3ris]

Python version

3.9.12

Expected Behavior

estimate_fee_sync should successfully complete

Current Behavior

It returns the following error:

{"code": "StarknetErrorCode.TRANSACTION_FAILED", "message": "Error at pc=0:392:\nUnknown value for memory cell at address 12:0.\nCairo traceback (most recent call last):\nUnknown location (pc=0:534)\nUnknown location (pc=0:468)"}

Possible Solution

Steps to Reproduce

(nonce,) = keeper_contract.functions["get_nonce"].call_sync()
task_address_felt = int(task["address"], 16)
args, signature = get_account_message_args_sig(keeper_address, registry, "executeTask", [task_address_felt], nonce, key)
unsigned_invocation = keeper_contract.functions["execute"].prepare(*args)

# This is where the error occurs
estimation = unsigned_invocation.estimate_fee_sync()

# This normally runs perfectly fine if I don't do gas estimation for all these transactions that are failing with `estimate_fee`
invocation = unsigned_invocation.invoke_sync(signature=signature, max_fee=0)

FYI - I'm using an older version of an account contract to issue transactions but I'm assuming that this should not impact estimate fee as the other starknet.py apis are working fine?

Context (Environment)

I've been using the excellent starknet.py library to power Yagi Keepers (http://www.yagi.fi/automation).
I'm trying to upgrade keepers now to use fees on testnet before they are officially mandated.

Detailed Description

Possible Implementation

[cptartur]

I've tried to replicate using both testnet and devnet using a simple balance contract I've deployed through cairo-lang CLI (I don't have the access to a contract you're using but I don't think that matters), but unfortunately/fortunately it works on my side. Intentionally changing parts of the prepared invoke function caused multiple errors but no like the one you provided.

Parhaps older account contract actually is an issue? In starknet.py 0.8.0 we've changed the way we're signing transactions to reflect changes made in the cairo-lang library itself. The way estimate_fee works it first has to construct the same InvokeFunction as invoke creates, but with signature=None and then passes it to estimate fee feeder gateway endpoint.

Or this may be an issue with contract/calldata/something but it's hard for me to speculate.

[Pet3ris]

Thanks so much @cptartur for the attempts to repro, I think I see what you mean - let me redeploy the latest account contract and I'll report back the findings!

[Pet3ris]

Unfortunately this didn't fix it, can I add you to my repo to have a look? Promise it's not super complex/nested at all :)

[cptartur]

Hey, I'd prefer if we kept this discussion here. Have you tried making the same calls are you trying to do in code through starknet CLI? Are they successful?

The error you've posted is from starknet, just forwared through starknet.py. There's of course a chance we have some bug in starknet.py code that's causing this but we'd need more details to verify it though.

Perhaps the ABI you're using to create a Contract instance isn't correct and that's why you don't get any errors in code but do on starknet?

[Solpatium]

@Pet3ris can you create a full repro showing your issue detached from your codebase? Ideally it would include deploying a simple contract before interacting with it.

[Pet3ris]

Hey @cptartur @Solpatium - thanks a lot for your guidance, I've done the above and created a separate repository to show how I'm using starknet.py.

The code and readme is available below:
https://github.com/Pet3ris/gas-estimation-example

FYI - I'm running gas estimation on a transaction that succeeds as an invoke with the same arguments, so I think the issue is not in the ABI but rather there is some behavioral difference between estimation and invocation.

[Solpatium]

@Pet3ris thank you for preparing a repro, it allowed us to find the issue - PreparedFunctionCall had no way of passing the signature. Usually AccountClient is used with Contract and it signs the tx automatically, but when using a bare Client that doesn't happen. This is why we couldn't reproduce it. We added a signature parameter to estimate_fee.
Fix: #217
It was already included in the latest release: https://github.com/software-mansion/starknet.py/releases/tag/0.3.4-alpha. Make sure you add your signature when calling estimate_fee.

Apart from that, I suggest using AccountClient instead of bare Client when sending txs. It hides signing and offers a higher-level api :)

[Pet3ris]

Legends @Solpatium !

[Pet3ris]

@Solpatium - I updated starknet.py to latest version but it's unfortunately still failing with the same error. Is there any other change I need to make in terms of how I'm using Client for this to work? I also tried to upgrade the openzeppelin account contract to latest and compiling it with 0.9.0 with no luck.

[cptartur]

Are you providing the same signature to Contract.estimate_fee() as you'd be using in Contract.invoke()?
It's

# create my_signature signature somehow
estimate = my_invoke.estimate_fee_sync(signature=my_signature)

[Pet3ris]

That fixed it thanks (and makes sense)!