Create Contract to send cw20 tokens over ics20 #238
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ethanfrey
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No time left for a proper require but I peeked and ❤️ it
contracts/cw20-ics20/src/ibc.rs
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| let res = IbcReceiveResponse { | ||
| acknowledgement: ack_success()?, | ||
| messages: vec![msg], | ||
| // TODO: similar event messages like ibctransfer module |
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Following event is emitted:
types.EventTypePacket,
sdk.NewAttribute(sdk.AttributeKeyModule, types.ModuleName),
sdk.NewAttribute(types.AttributeKeyReceiver, data.Receiver),
sdk.NewAttribute(types.AttributeKeyDenom, data.Denom),
sdk.NewAttribute(types.AttributeKeyAmount, fmt.Sprintf("%d", data.Amount)),
sdk.NewAttribute(types.AttributeKeyAckSuccess, fmt.Sprintf("%t", err != nil)),There was a problem hiding this comment.
ohh.... this is a very important and very major issue!
packet and acknowledgements are never stored in the iavl tree, but rather their hashes are there and you need to get the preimage from the events.
When we submit SendPacket, this is handled in wasmd and should emit such a packet (need to check). Since the contract cannot create custom event types, we need to also auto-emit such an event in wasmd for acknowledgements. Otherwise we cannot relay such packets.
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Okay, investigated a bit more. The ChannelKeeper manages all the essential events.
On SendPacket and WriteAcknowledgement
In wasmd, we call SendPacket on receiving the IbcMsg::SendPacket. However, I cannot find where WriteAcknowledgement is called.
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Update: We return the acknowledgement from IbcModule.OnRecvPacket in x/wasm.
That is the same pattern that is used in ibctransfer and when digging deeper, I see that the acknowledgement is written by the ibc msg server.
So, it looks like we don't need to do anything here, but add some app-specific attributes
| cur.outstanding = (cur.outstanding - amount)?; | ||
| Ok(cur) | ||
| }, | ||
| )?; |
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I don't fully understand this block so I may go this wrong. The "no funds" is an IBC application level error that is part of the payload and should not result in an error that reverts the TX in the module.
See https://github.com/cosmos/cosmos-sdk/blob/v0.41.4/proto/ibc/core/channel/v1/channel.proto#L145
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You are very correct here.
I made a separate function in 0844e34 so that I can catch the errors and turn them into "acknowledgement messages containing errors".
ethanfrey
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Rebased with I'd like a review, but I guess I merge if no blockers and test with the relayer. There will likely be a few more follow up PRs on this anyway, so happy for comments even after a merge |
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Closes #226