basho/cuttlefish — pull request #102 by rzezeski (2014-01-09 04:03:52+00:00)
Title: Give more helpful output during generate failure

I am trying to make a stagedevrel on riak-pre9 and keep getting this error.

```
ERROR: generate failed while processing /root/yz-src-verify/riak_yz/rel: {'EXIT',
{badarg,
[{io_lib,format,
["Default: ~s",
[{error,"could not convert off of type flag to a string"}]],
[{file,"io_lib.erl"},{line,155}]},
{cuttlefish_conf,generate_comments,1,
[{file,"src/cuttlefish_conf.erl"},{line,125}]},
...
```

It is kind of helpful but gives me no idea which file/mapping generated it. This patch adds more info.

```
ERROR: generate failed while processing /root/yz-src-verify/riak_yz/rel: {{mapping,["dtrace"],
"riak_core.dtrace_support",off,undefined,
[flag],
basic,
["DTrace support Do not enable 'dtrace' unless your Erlang/OTP",
"runtime is compiled to support DTrace. DTrace is available in",
"R15B01 (supported by the Erlang/OTP official source package) and in",
"R14B04 via a custom source repository & branch."],
undefined,[],false,[]},
badarg,
[{io_lib,format,
["Default: ~s",
[{error,"could not convert off of type flag to a string"}]],
[{file,"io_lib.erl"},{line,155}]},
...
```