nautechsystems/nautilus_trader · error

RPC parsing of collect event is not defined in this dex: {}:

Error message

RPC parsing of collect event is not defined in this dex: {}:{}

What it means

Raised by `DexExtended::parse_collect_event_rpc` when the DEX has no RPC collect-event parser registered (`parse_collect_event_rpc_fn` is `None`). Collect events (position fee collection in V3-style DEXes) must be opted into per adapter; this DEX does not provide an RPC log parser for them, so the call bails with the chain and DEX name.

Source

Thrown at crates/adapters/blockchain/src/exchanges/extended.rs:526

        } else {
            anyhow::bail!(
                "RPC parsing of initialize event is not defined in this dex: {}:{}",
                self.dex.chain,
                self.dex.name
            )
        }
    }

    /// Parses a collect event from an RPC log.
    ///
    /// # Errors
    ///
    /// Returns an error if the DEX does not have an RPC collect event parser defined or if parsing fails.
    pub fn parse_collect_event_rpc(&self, log: &RpcLog) -> anyhow::Result<CollectEvent> {
        if let Some(parse_fn) = &self.parse_collect_event_rpc_fn {
            parse_fn(self.dex.clone(), log)
        } else {
            anyhow::bail!(
                "RPC parsing of collect event is not defined in this dex: {}:{}",
                self.dex.chain,
                self.dex.name
            )
        }
    }

    /// Parses a flash event from an RPC log.
    ///
    /// # Errors
    ///
    /// Returns an error if the DEX does not have an RPC flash event parser defined or if parsing fails.
    pub fn parse_flash_event_rpc(&self, log: &RpcLog) -> anyhow::Result<FlashEvent> {
        if let Some(parse_fn) = &self.parse_flash_event_rpc_fn {
            parse_fn(self.dex.clone(), log)
        } else {
            anyhow::bail!(
                "RPC parsing of flash event is not defined in this dex: {}:{}",

View on GitHub (pinned to 18893faf8b)

Solutions

1. Register the collect RPC parser on the DEX at construction time (`parse_collect_event_rpc_fn: Some(...)`).
2. Guard the call: only invoke `parse_collect_event_rpc` when the parser fn is present; otherwise skip the log and record the DEX/chain.
3. Filter Collect topic0 out of your RPC log subscription for this DEX if collect data is not required.
4. Check the adapter's registered parser list (or tests like the ones calling these parse functions) to confirm which events that DEX supports.

Example fix

// before
let ev = dex.parse_collect_event_rpc(&log)?;
// after
match dex.parse_collect_event_rpc(&log) {
    Ok(ev) => handle(ev),
    Err(e) if e.to_string().contains("not defined in this dex") => tracing::debug!("collect rpc parser unsupported for {}:{}", dex.dex.chain, dex.dex.name),
    Err(e) => return Err(e),
}

if dex.parse_collect_event_rpc_fn.is_none() {
    tracing::debug!("collect rpc parsing unsupported for {}:{}", dex.dex.chain, dex.dex.name);
    return Ok(());
}

fn supports_collect_rpc(dex: &DexExtended) -> bool {
    dex.parse_collect_event_rpc_fn.is_some()
}

match dex.parse_collect_event_rpc(&log) {
    Ok(ev) => handle_collect(ev),
    Err(e) if e.to_string().contains("not defined in this dex") => Ok(()),
    Err(e) => Err(e),
}

When it happens

Trigger: Calling `dex.parse_collect_event_rpc(&log)` on a `DexExtended` constructed without `parse_collect_event_rpc_fn` set — e.g. routing Collect logs from an RPC subscription to a DEX adapter that never registered a collect RPC parser.

Common situations: Replaying historical Collect logs via eth_getLogs/subscription for a DEX whose adapter only wires Hypersync parsing; copying a DEX setup from a minimal example that omits the collect parser; new chain support added before all event parsers were wired.

Related errors

• RPC parsing of initialize event is not defined in this dex:
• RPC parsing of flash event is not defined in this dex: {}:{}
• RPC parsing of SetFeeProtocol event is not defined in this d
• RPC parsing of CollectProtocol event is not defined in this
• RPC parsing of pool created event is not defined in this dex

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/7c0e0330f79254e4. Report an issue: GitHub.