risingwavelabs/risingwave · error · ConnectorError

No allow_alter_on_fly fields registered for connector

Error message

No allow_alter_on_fly fields registered for connector: {connector_name}

What it means

Raised when the connector name resolves to a known source type but SOURCE_ALLOW_ALTER_ON_FLY_FIELDS has no entry for it, meaning no fields have been registered as alterable on the fly for that source connector.

Solutions

  1. Re-run the code generation that populates SOURCE_ALLOW_ALTER_ON_FLY_FIELDS (generate_allow_alter_on_fly_fields_combined / build step).
  2. If the connector genuinely supports no on-the-fly field alterations, do not call this validation for it (guard on registration first).
  3. Add an allow_alter_on_fly field list for the connector in the source definition and regenerate.

Example fix

// before
check_source_allow_alter_on_fly_fields(connector, fields)?;
// after
if source_properties::source_name_to_prop_type_name(connector).and_then(|t| SOURCE_ALLOW_ALTER_ON_FLY_FIELDS.get(t)).is_some() {
    check_source_allow_alter_on_fly_fields(connector, fields)?;
}
Defensive patterns

Strategy: type-guard

Validate before calling

fn source_has_alter_fields(connector: &str) -> bool {
    source_properties::source_name_to_prop_type_name(connector)
        .and_then(|t| SOURCE_ALLOW_ALTER_ON_FLY_FIELDS.get(t))
        .is_some()
}

Try / catch

if let Err(e) = check_source_allow_alter_on_fly_fields(connector, &fields) {
    log::warn!("skipping on-the-fly alteration check: {e}");
}

Prevention

When it happens

Trigger: Calling check_source_allow_alter_on_fly_fields with a valid connector name whose allow-alter-on-fly field list was never generated/registered (the generator did not run or the connector has no eligible fields).

Common situations: Hand-editing a new connector without re-running the code generator; connector exists but intentionally (or mistakenly) has no allow_alter_on_fly registry entry; stale build where generated code is outdated.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

AI-assisted analysis of risingwavelabs/risingwave@6469eb736d (2026-09-11). Data as JSON: /api/errors/e3fa907d00408f9b. Report an issue: GitHub.

Appendix: source

Thrown at src/connector/src/with_options_test.rs:801

/// Get all connection names that have `allow_alter_on_fly` fields
pub fn get_connection_names_with_allow_alter_on_fly_fields() -> Vec<&'static str> {{
    CONNECTION_ALLOW_ALTER_ON_FLY_FIELDS.keys().map(|s| s.as_str()).collect()
}}

/// Checks if all given fields are allowed to be altered on the fly for the specified source connector.
/// Returns Ok(()) if all fields are allowed, otherwise returns a `ConnectorError`.
pub fn check_source_allow_alter_on_fly_fields(
    connector_name: &str,
    fields: &[String],
) -> crate::error::ConnectorResult<()> {{
    // Convert connector name to the type name key
    let Some(type_name) = source_properties::source_name_to_prop_type_name(connector_name) else {{
        return Err(ConnectorError::from(anyhow::anyhow!(
            "Unknown source connector: {{connector_name}}"
        )));
    }};
    let Some(allowed_fields) = SOURCE_ALLOW_ALTER_ON_FLY_FIELDS.get(type_name) else {{
    return Err(ConnectorError::from(anyhow::anyhow!(
        "No allow_alter_on_fly fields registered for connector: {{connector_name}}"
    )));
    }};
    for field in fields {{
        if !allowed_fields.contains(field) {{
            return Err(ConnectorError::from(anyhow::anyhow!(
                "Field '{{field}}' is not allowed to be altered on the fly for connector: {{connector_name}}"
            )));
        }}
    }}
    Ok(())
}}

pub fn check_connection_allow_alter_on_fly_fields(
    connection_name: &str,
    fields: &[String],
) -> crate::error::ConnectorResult<()> {{
    use crate::source::connection_name_to_prop_type_name;

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