printf 'a\nb\n' > old; printf 'a\nc\n' > new

$ ./target/release/diffutils diff --color=always --palette='ad=\061;32' old new | tail -1 | cat -v
^[[\061;32m> c^[[0m
# Exit code: 0   (of the pipeline; diff itself exits 1)

$ LC_ALL=C diff --color=always --palette='ad=\061;32' old new | tail -1 | cat -v
^[[1;32m> c^[[0m
# Exit code: 0   (of the pipeline; diff itself exits 1)

for entry in spec.split(':').filter(|entry| !entry.is_empty()) {
    let Some((name, value)) = entry.split_once('=') else {
        return Err(PaletteError::Unparsable);
    };
    ...
    value.clone_into(slot);

#[test]
fn palette_decodes_escapes() -> Result<(), Box<dyn std::error::Error>> {
    let mut old = NamedTempFile::new()?;
    old.write_all(b"a\nb\n")?;
    let mut new = NamedTempFile::new()?;
    new.write_all(b"a\nc\n")?;
    let mut cmd = cargo_bin_cmd!("diffutils");
    cmd.arg("diff")
        .arg("--color=always")
        .arg(r"--palette=ad=\061;32")
        .arg(old.path())
        .arg(new.path());
    cmd.assert()
        .code(predicate::eq(1))
        .stdout(predicate::str::contains("\x1b[1;32m> c\x1b[0m"));
    Ok(())
}