rebar.config.script

% vim: set ft=erlang:
case erlang:function_exported(rebar3, main, 1) orelse
     {deps, lists:keyfind(deps, 1, CONFIG)}
of
    true ->
        % rebar3
        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[locus] 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 ({stacktrace_compat, Version}, Acc) ->
                      [{1, {stacktrace_compat, ".*", {git, "https://github.com/g-andrade/stacktrace_compat.git",
                                                      {tag, Version}}}}
                       | Acc];
                  ({certifi, Version}, Acc) ->
                      [{2, {certifi, ".*", {git, "https://github.com/certifi/erlang-certifi.git",
                                            {tag, Version}}}},
                       %% XXX we don't actually need parse_trans, but certifi imports it
                       %% from hex.pm, which would make it impossible to build it on rebar 2.
                       {2, {parse_trans, ".*", {git, "https://github.com/uwiger/parse_trans.git",
                                                {tag, "3.3.0"}}}}
                       | Acc];
                  ({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.