What causes "cannot find field type for {}" in risingwavelabs/risingwave?

This is an internal invariant error; report it with the sink definition if seen

risingwavelabs/risingwave · error · SinkError

cannot find field type for {}

Error message

cannot find field type for {}

What it means

Defensive lookup after the contains_key check: `deltalake_fields.get(&field.name)` is expected to succeed, and its absence is reported as 'cannot find field type for <name>'. In practice it is nearly unreachable because the presence check at line 446 runs first.

Source

Thrown at src/connector/src/sink/deltalake.rs:452

            .fields()
            .map(|f| (f.name(), f.data_type()))
            .collect();
        if deltalake_fields.len() != self.param.schema().fields().len() {
            return Err(SinkError::DeltaLake(anyhow!(
                "Columns mismatch. RisingWave schema has {} fields, DeltaLake schema has {} fields",
                self.param.schema().fields().len(),
                deltalake_fields.len()
            )));
        }
        for field in self.param.schema().fields() {
            if !deltalake_fields.contains_key(&field.name) {
                return Err(SinkError::DeltaLake(anyhow!(
                    "column {} not found in deltalake table",
                    field.name
                )));
            }
            let deltalake_field_type = deltalake_fields.get(&field.name).ok_or_else(|| {
                SinkError::DeltaLake(anyhow!("cannot find field type for {}", field.name))
            })?;
            if !check_field_type(&field.data_type, deltalake_field_type)? {
                return Err(SinkError::DeltaLake(anyhow!(
                    "column '{}' type mismatch: deltalake type is {:?}, RisingWave type is {:?}",
                    field.name,
                    deltalake_field_type,
                    field.data_type
                )));
            }
        }
        if self.config.common.commit_checkpoint_interval == 0 {
            return Err(SinkError::Config(anyhow!(
                "`commit_checkpoint_interval` must be greater than 0"
            )));
        }
        Ok(())
    }

View on GitHub (pinned to 6469eb736d)

Solutions

This is an internal invariant error; report it with the sink definition if seen
Re-run validation after confirming the earlier 'column not found' error was not masked
Upgrade RisingWave in case the duplicate-check code path was fixed

Defensive patterns

Strategy: try-catch

Try / catch

match sink_creation_result {
    Err(e) if e.to_string().contains("cannot find field type for") => {
        report_internal_bug(e); // invariant violation, not user-fixable
    }
    Err(e) => handle_config_error(e),
    Ok(_) => {}
}

Prevention

If seen, file a bug with the full sink DDL — the code path is expected to be unreachable
Apply the fixes for errors 385/386 since those guards normally prevent this path

When it happens

Trigger: Only reachable if the HashMap lookup fails despite the prior `contains_key` guard passing — essentially an invariant violation inside validate's field loop.

Common situations: Rarely hit by users; indicates an internal inconsistency in the validation code path rather than a user configuration problem.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

AI-assisted analysis of risingwavelabs/risingwave@6469eb736d (2026-09-11). Data as JSON: /api/errors/adf0b6eb93805c49. Report an issue: GitHub.