maybeUpdateName

fn maybeUpdateName(wf: *WriteFile) void {
    const graph = wf.step.owner.graph;
    const wc = &graph.wip_configuration;
    const files_count = wf.embeds.items.len + wf.copies.items.len;
    if (files_count == 1 and wf.directories.items.len == 0) {
        // First time adding a file; update name.
        const sub_path = if (wf.embeds.items.len == 1) wf.embeds.items[0].sub_path else wf.copies.items[0].sub_path;
        if (std.mem.eql(u8, wf.step.name, "WriteFile")) {
            wf.step.name = wf.step.owner.fmt("WriteFile {s}", .{wc.stringSlice(sub_path)});
        }
    } else if (wf.directories.items.len == 1 and files_count == 0) {
        // First time adding a directory; update name.
        const dir_name = wc.stringSlice(wf.directories.items[0].sub_path);
        if (std.mem.eql(u8, wf.step.name, "WriteFile")) {
            wf.step.name = wf.step.owner.fmt("WriteFile {s}", .{dir_name});
        }
    }
}