Function build_vector_search_request

nodedb-client/src/native/client/vector.rs:88–111

Build the `TextFields` payload for an `OpCode::VectorSearch` request. The native protocol reserves wire byte 68 for the optional `TextFields::filters: Option >` field. When the trait caller passes a non-`None` `MetadataFilter`, the predicate is serialized here so it travels alongside the SQL/DSL request rather than being dropped at the client. Wire-format note: the inline doc on `TextFiel

(
    collection: &str,
    query: &[f32],
    k: usize,
    filter: Option<&MetadataFilter>,
)

/// both sides to a single agreed encoding; for now the bytes are
/// observable as non-empty, which is what the trait contract requires.
pub(super) fn build_vector_search_request(
    collection: &str,
    query: &[f32],
    k: usize,
    filter: Option<&MetadataFilter>,
) -> NodeDbResult<TextFields> {
    // Serialization failure here must surface to the caller. Dropping
    // the filter and sending the request anyway would send the query
    // to the server without the caller's predicate — exactly the
    // silent-drop pattern this client guards against.
    let filters_bytes = match filter {
        Some(f) => Some(sonic_rs::to_vec(f).map_err(|e| {
            NodeDbError::serialization("json", format!("vector_search metadata filter: {e}"))
        })?),
        None => None,
    };
    Ok(TextFields {
        collection: Some(collection.to_string()),
        query_vector: Some(query.to_vec()),
        top_k: Some(k as u32),
        filters: filters_bytes,
        ..Default::default()
    })
}

/// Format a `&[f32]` as a SQL `ARRAY[...]` literal.
pub(super) fn format_f32_array(arr: &[f32]) -> String {