Function branch_files 

pub async fn branch_files(
    root: &str,
    base: Option<&str>,
    head: &str,
) -> Vec<String>

The files a PR from head into base changes in root: git diff --name-only base...head, the base being origin/<base> (or a local <base>), else the default branch (origin/HEAD, origin/main, origin/master), and the head a local branch, else origin/<head>. Empty when either can’t be found, on the base itself, or when git can’t say in PROBE_TIMEOUT. A diff of two commits: no working-tree filter runs.