distel:get_arglists("json2", "encode") crash distel every time

[leoliu]

So I was using distel with yaws and found this bug. Tested on Mac OS X with Erlang R16B03 and yaws 1.98.

(devel@localhost)23> catch distel:src_args(Forms, encode, 1).
{'EXIT',{function_clause,[{distel,src_args,
                                  [[],encode,1],
                                  [{file,"distel.erl"},{line,938}]}]}}

distel:src_args has this comment: %% if we get to [] we have a serious error.

This is due to the pattern match in distel:src_args doesn't match against func but function. An example element of the Forms argument looks like this:

{tree,function,
       {attr,98,[],none},
       {func,{tree,atom,{attr,98,[],none},encode_string},
             [{tree,clause,
                    {attr,98,[],none},
                    {clause,[{var,98,'B'}],
                            {tree,disjunction,{...},...},
                            [{tree,...}]}},
              {tree,clause,
                    {attr,99,[],none},
                    {clause,[{var,99,...}],none,[{...}]}}]}}

[massemanet]

can you post an example of erlang code that triggers this?

[leoliu]

Get json2 from https://raw.github.com/klacke/yaws/master/src/json2.erl and compile without debug_info and load it.
Eval this in the eshell:

catch distel:get_arglists("json2", "encode").