What causes "RPC parsing of burn event is not defined in this dex: {}:{}" in nautechsystems/nautilus_trader?

Register parse_burn_event_rpc_fn for the DEX at construction time.

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

Error message

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

What it means

Raised by parse_burn_event_rpc when no RPC burn-event parser (parse_burn_event_rpc_fn) is registered on the DEX. Burn events represent liquidity removal; when the parser slot is None the method bails with chain:name. Like the other parser-gap errors, it is a configuration/capability signal rather than malformed input.

Source

Thrown at crates/adapters/blockchain/src/exchanges/extended.rs:492

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

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

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

View on GitHub (pinned to 18893faf8b)

Solutions

Register parse_burn_event_rpc_fn for the DEX at construction time.
Use the DEX's HyperSync burn parser (parse_burn_event_hypersync) when RPC parsing is unsupported.
Filter burn topics away from DEXs lacking RPC support before dispatch.
Confirm the log's emitting contract maps to this DEX.

Defensive patterns

Strategy: try-catch

Validate before calling

if !dex_supports(dex, DexEvent::BurnRpc) { return Ok(()); }

Type guard

fn has_rpc_burn_parser(dex: &Dex) -> bool { dex.parse_burn_event_rpc_fn.is_some() }

Try / catch

match dex.parse_burn_event_rpc(&log) {
    Ok(evt) => handle_burn(evt),
    Err(e) if e.to_string().contains("not defined in this dex") => tracing::debug!("RPC burn parsing unsupported on {}", dex.name()),
    Err(e) => return Err(e),
}

Prevention

Register burn parsers alongside mint parsers to keep liquidity tracking symmetric.
Gate RPC subscriptions on each DEX's registered parser set.
Confirm the emitting contract belongs to this DEX before parsing.
Include burn-event coverage in per-DEX integration tests.

When it happens

Trigger: Calling dex.parse_burn_event_rpc(&log) on RPC liquidity-removal logs for a DEX that never registered an RPC burn parser.

Common situations: RPC-based liquidity tracking on HyperSync-only DEX adapters; incomplete new-DEX registration; forks with divergent Burn event signatures left unimplemented over RPC.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/8ab966a4101d08de. Report an issue: GitHub.