quickwit-oss/quickwit · error

duplicated field definition `{}`

Error message

duplicated field definition `{}`

What it means

While building the mapping tree from the field mapping entries, two entries resolved to the same field path (e.g. an explicit field colliding with a property defined via an object/JSON subtree). The schema builder cannot hold two definitions for one field, so the duplicate is rejected with its full name.

Source

Thrown at quickwit/quickwit-doc-mapper/src/doc_mapper/mapping_tree.rs:1031

    let mut field_path = Vec::new();
    build_mapping_tree_from_entries(entries, &mut field_path, schema)
}

fn build_mapping_tree_from_entries<'a>(
    entries: &'a [FieldMappingEntry],
    field_path: &mut Vec<&'a str>,
    schema: &mut SchemaBuilder,
) -> anyhow::Result<MappingNodeRoot> {
    let mut mapping_node = MappingNode::default();
    let mut concatenate_fields = Vec::new();
    let mut concatenate_dynamic_fields = Vec::new();
    for entry in entries {
        if let FieldMappingType::Concatenate(_) = &entry.mapping_type {
            concatenate_fields.push(entry);
        } else {
            field_path.push(&entry.name);
            if mapping_node.branches.contains_key(&entry.name) {
                bail!("duplicated field definition `{}`", entry.name);
            }
            let (child_tree, mut dynamic_fields) =
                build_mapping_from_field_type(&entry.mapping_type, field_path, schema)?;
            field_path.pop();
            mapping_node.insert(&entry.name, child_tree);
            concatenate_dynamic_fields.append(&mut dynamic_fields);
        }
    }
    for concatenate_field_entry in concatenate_fields {
        let FieldMappingType::Concatenate(options) = &concatenate_field_entry.mapping_type else {
            // we only pushed Concatenate fields in `concatenate_fields`
            unreachable!();
        };
        let name = &concatenate_field_entry.name;
        if mapping_node.branches.contains_key(name) {
            bail!("duplicated field definition `{}`", name);
        }
        let text_options: JsonObjectOptions = options.clone().into();

View on GitHub (pinned to a39730c5cd)

Solutions

1. Remove or rename the duplicate field definition in the index config mapping.
2. If merging configs programmatically, deduplicate entries by name before building the tree.
3. Search the YAML/JSON mapping for repeated keys (some editors hide duplicate keys).

Example fix

// before
mapping:
  message:
    type: text
  message:
    type: json
// after
mapping:
  message:
    type: text

fn check_duplicate_fields(mapping: &serde_yaml::Mapping) -> Result<(), String> {
    let mut seen = std::collections::HashSet::new();
    for (k, _) in mapping {
        if !seen.insert(k.clone()) {
            return Err(format!("duplicated field definition `{k:?}`"));
        }
    }
    Ok(())
}

match result {
    Err(e) if e.to_string().contains("duplicated field definition") => {
        // surface the offending config path to the user
    }
    Err(e) => return Err(e),
    Ok(v) => v,
}

When it happens

Trigger: Calling build_mapping_tree (index config load / DocMapping validation) with a mapping containing two fields of the same name in the same object, e.g. `message` declared twice, including duplicates arising from nested objects each contributing a child of the same name.

Common situations: Merged index configs where two include files define the same field; YAML anchors or generated mappings appending a field twice; a copy-pasted field block left in place during edits.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• field name is empty
• field name `{}` must not start with a dot `.`
• field name `{}` is too long. field names must not be longer
• field name `{}` is invalid. field names must start with an u
• field name `{}` contains illegal characters. field names mus

AI-assisted analysis of quickwit-oss/quickwit@a39730c5cd (2026-09-08). Data as JSON: /api/errors/0150e6ebfc84d6a8. Report an issue: GitHub.