Failed to resolve log with anonymous argument

[rjl493456442]

Solidity allows developers to define some event with anonymous arguments. But the abi library can't resolve this type of log correctly.

Testing contract

pragma solidity >=0.6.0 <0.7.0;

contract MyContract {
    event MyEvent(address);
    
    function foo() public {
        emit MyEvent(msg.sender);
    }
}

Testing scripts

package anno

import (
	"math/big"
	"testing"
	"time"

	"github.com/ethereum/go-ethereum/accounts/abi/bind"
	"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
	"github.com/ethereum/go-ethereum/core"
	"github.com/ethereum/go-ethereum/crypto"
)

func TestAnno(t *testing.T) {
	key, _ := crypto.GenerateKey()
	addr := crypto.PubkeyToAddress(key.PublicKey)

	sim := backends.NewSimulatedBackend(core.GenesisAlloc{addr: {Balance: big.NewInt(1000000000)}}, 10000000)
	defer sim.Close()

	opts := bind.NewKeyedTransactor(key)
	_, _, c, err := DeployAnno(opts, sim)
	if err != nil {
		t.Error("Failed to deploy contract", err)
	}
	sim.Commit()

	shutdown := make(chan struct{})
	defer close(shutdown)

	verifier := make(chan struct{}, 1)
	go func() {
		sink := make(chan *AnnoMyEvent)
		sub, err := c.WatchMyEvent(nil, sink)
		if err != nil {
			t.Errorf("Failed to monitor event %v", err)
			return
		}
		defer sub.Unsubscribe()

		select {
		case <-shutdown:
			return
		case <-sink:
			verifier <- struct{}{}
		}
	}()

	c.Foo(opts)
	sim.Commit()

	select {
	case <-verifier:
		return
	case <-time.After(time.Second):
		t.Fatalf("No event arrives")
	}
}

Expected behaviour

The unit test above should be able to pass

Actual behaviour

Failed

Steps to reproduce the behaviour

• Compile the solidity code
• Generate go-binding via abigen
• Run the scripts above

[MariusVanDerWijden]

Hey @rjl493456442 I did a bit of digging and I think the main issue is in reflect::mapArgNamesToStructFields. In line https://github.com/ethereum/go-ethereum/blob/master/accounts/abi/reflect.go#L192 an error is thrown because the name is always "".

[rjl493456442]

@MariusVanDerWijden Yes exactly. Hope it can enter your radar when you fix or refactor the abi library :P

[MariusVanDerWijden]

I found a really ugly fix :D I'll spend more time refactoring everything around it, maybe I'll find a better fix.

[rjl493456442]

Fixed by #20895