Function format_combined_textconv_patch 

pub fn format_combined_textconv_patch(
    git_dir: &Path,
    config: &ConfigSet,
    odb: &Odb,
    path: &str,
    parent_trees: &[ObjectId],
    result_tree: &ObjectId,
    abbrev: usize,
    context: usize,
    use_cc_word: bool,
    use_textconv: bool,
    ws: CombinedDiffWsOptions,
    combined_all_paths: bool,
    parent_blob_paths: Option<&[String]>,
    parent_sides: &[CombinedParentSide],
    quote_path_fully: bool,
) -> Option<String>

Combined text diff with optional textconv (N parents, single merge path).

parent_blob_paths — when set, length must match parent_trees; each entry is the path used to read that parent’s blob (for --combined-all-paths rename cases). When None, every parent uses path.