Indexed arg filters ignore ABI position; non‑first indexed args map to wrong topic offsets #90
Description
logPredicates in internal/usecase/eventtrigger.go assigns indexed topic offsets by the order of the provided JSON arguments, not by the ABI input’s actual position, which leads to the incorrect trigger definition, and causes non-first indexed args to be matched against the wrong topic.
In an EventTransfer(indexed address from, indexed address to, unit value), if the user provides a condition on the "to" argument alone, the predicate offset is set to 1 and therefore compared to the first topic in the log. The trigger therefore never fires.
As a workaround for testing, it is possible to provide all indexed arguments in ABI order so offsets are lined up, if the values can be set to one value.
Correction: Derive the indexed argument offset from the ABI input's position, then assign that offset to the corresponding argument predicate. Here we are using an incremented counter: https://github.com/shutter-network/shutter-api/blob/main/internal/usecase/eventtrigger.go#L183