Function check_metadata_with_storage_equal

datafusion/common/src/metadata.rs:86–124

Assert equality of data types where one or both sides may have field metadata This currently compares absent metadata (e.g., one side was a DataType) and empty metadata (e.g., one side was a field where the field had no metadata) as equal and uses byte-for-byte comparison for the keys and values of the fields, even though this is potentially too strict for some cases (e.g., extension types where

(
    actual: (
        &DataType,
        Option<&std::collections::HashMap<String, String>>,
    ),
    expected: (
        &DataType,
        Option<&std::collections::HashMap<String, String>>,
   

/// Returns a planning error with suitably formatted type representations if
/// actual and expected do not compare to equal.
pub fn check_metadata_with_storage_equal(
    actual: (
        &DataType,
        Option<&std::collections::HashMap<String, String>>,
    ),
    expected: (
        &DataType,
        Option<&std::collections::HashMap<String, String>>,
    ),
    what: &str,
    context: &str,
) -> Result<(), DataFusionError> {
    if actual.0 != expected.0 {
        return _plan_err!(
            "Expected {what} of type {}, got {}{context}",
            format_type_and_metadata(expected.0, expected.1),
            format_type_and_metadata(actual.0, actual.1)
        );
    }

    let metadata_equal = match (actual.1, expected.1) {
        (None, None) => true,
        (None, Some(expected_metadata)) => expected_metadata.is_empty(),
        (Some(actual_metadata), None) => actual_metadata.is_empty(),
        (Some(actual_metadata), Some(expected_metadata)) => {
            actual_metadata == expected_metadata
        }
    };

    if !metadata_equal {
        return _plan_err!(
            "Expected {what} of type {}, got {}{context}",
            format_type_and_metadata(expected.0, expected.1),
            format_type_and_metadata(actual.0, actual.1)
        );
    }

    Ok(())
}

/// Given a data type represented by storage and optional metadata, generate
/// a user-facing string