Using Ethers to Find ETH sent from a contract to the method caller.

Hey there!

First of all, thank you so much for the time you put into this library. It’s without question my favorite to work with.

I’m having a hard time figuring out how to see when a contract method returns ether to the sender. For example in the transaction 0x57d0a98e69c19195e0283358240b888ea06be8f4473f73c770ab6126c8278e82 wETH is being ‘Unwrapped’ and the contract is sending ether to the caller. Nothing jumps out to me when inspecting the TransactionResponse and TransactionReceipt. I’ve been looking through the docs and other issues and I haven’t been able to find a solution.

Any insight would be greatly appreciated.

[zemse]

You cannot see that through ethers.js directly. When contract sends ether to some address it is an internal transaction, which uses CALL opcode. Internal transactions aren’t included in receipts. To get ETH transfers you need to replay the transaction in EVM and check all CALL opcode uses in the stack, and from that just filter out those CALL uses with positive value.

But this process is non-trivial since different backends have different RPC APIs for the same thing. For example, in OpenEthereum it’s trace_replayTransaction and geth it’s debug_tracetransaction. Only name isn’t different but the responses are also different.

Last month, while writing test cases I wrote some code to see contract ETH transfers in ganache, the repo is public you can see it here if you are interested. I’m not sure if ganache’s response is same like geth, if it is then that code might work with geth too (I haven’t tried that in geth).

Also, Infura doesn’t support tracing yet in their APIs. I posted a request in their forum for the same and they seem to be positive to add it.

[travisallen6]

I definitely noticed that etherscan shows that ether was sent to the caller. I’m hoping there is a way to see that the contract method sent ether to the caller using the library.