[SUBGRAPH] Investigate issues with `Approval` event mapping

[kasparkallas]

What?

The ERC-20 Approval event should be mapped to the subgraph. The addresses field should contain the relevant addresses for the user products to show the event in activity history views.

Currently, the event doesn't show up. At a quick glance, there is something off with the mapping. There seems to be two events with the same name:

• approval for ERC-20 allowance
• approval for FlowNFT

The mapping for FlowNFT approval event definitely has addresses missing.

I didn't find the mapping for ERC-20 approval event. I could only find it being handled for the FlowOperator entity: https://github.com/superfluid-finance/protocol-monorepo/blob/fa5a75dbaf85af9f60a03b224a9c29f1bf214fa7/packages/subgraph/src/mappings/superToken.ts#L454

When querying from Mumbai, this error shows up:

Why?

The ERC-20 approval event is important and should be properly mapped to the subgraph.

[0xdavinchee]

Thoughts on the TODOS? @kasparkallas

• [x] Add mapping for missing addresses property
• [x] handle SuperToken Approval event in superToken.ts
• [x] Add a new field indicating whether it is Approval event for ERC-721 or ERC-20

[0xdavinchee]

resolved with #1878