rebar.config.script

% vim: set ft=erlang:
case erlang:function_exported(rebar3, main, 1)
     orelse erlang:function_exported('Elixir.Mix', module_info, 1)
     orelse {deps, lists:keyfind(deps, 1, CONFIG)}
of
    true ->
        % either rebar3 or mix
        CONFIG;
    {deps, false} ->
        % no override needed
        CONFIG;
    {deps, {_, Deps}} ->
        %
        % rebar 2.x - convert deps to old format
        % THIS MAY STOP WORKING AT ANY MOMENT.
        % USE AT YOUR OWN RISK.
        %
        error_logger:warning_msg("~n~n"
                                 "\t!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!~n"
                                 "\t!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!~n"
                                 "\t*********************************************************************~n"
                                 "\t~n"
                                 "\t[tls_certificate_check] You're **strongly** incentivized to use `rebar3`.~n"
                                 "\tCompatibility with rebar 2 is unmaintained and will be removed in the near future.~n"
                                 "\t~n"
                                 "\t*********************************************************************~n"
                                 "\t!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!~n"
                                 "\t!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!~n"),

        {_, ErlOpts} = lists:keyfind(erl_opts, 1, CONFIG),
        OverriddenErlOpts = ErlOpts -- [warn_missing_spec],
        OverriddenSortableDeps =
            lists:foldr(
              fun ({ssl_verify_fun, Version}, Acc) ->
                      [{3, {ssl_verify_fun, ".*", {git, "https://github.com/deadtrickster/ssl_verify_fun.erl.git",
                                                   {tag, Version}}}}
                       | Acc];
                  ({Name, Version}, _Acc) ->
                      MsgErrorIo = io_lib:format("Hex package '~ts', version \"~ts\": missing Git repo",
                                                 [Name, Version]),
                      error(MsgErrorIo)
              end,
              [], Deps),

        OverriddenDeps = [element(2, Pair) || Pair <- lists:keysort(1, OverriddenSortableDeps)],
        Config2 = lists:keystore(deps, 1, CONFIG, {deps,OverriddenDeps}),
        lists:keystore(erl_opts, 1, Config2, {erl_opts,OverriddenErlOpts})
end.