decode: catch binary_to_integer exceptions for 2nd surrogate

Signed-off-by: Stephan Renatus <srenatus@chef.io>

src/jsone_decode.erl

@@ -199,11 +199,12 @@ unicode_string(<<N:4/binary, Bin/binary>>, Start, Nexts, Buf, Opt) ->
             %% surrogate pair
             case Bin of
                 <<$\\, $u, N2:4/binary, Bin2/binary>> ->
-                    case binary_to_integer(N2, 16) of
+                    try binary_to_integer(N2, 16) of
                         Low when 16#DC00 =< Low, Low =< 16#DFFF ->
                             <<Unicode/utf16>> = <<High:16, Low:16>>,
                             string(Bin2, Start, Nexts, <<Buf/binary, Unicode/utf8>>, Opt);
                         _ -> ?ERROR(unicode_string, [<<N/binary, Bin/binary>>, Start, Nexts, Buf, Opt])
+                    catch error:badarg -> ?ERROR(unicode_string, [<<N/binary, Bin/binary>>, Start, Nexts, Buf, Opt])
                     end;
                 _ -> ?ERROR(unicode_string, [<<N/binary, Bin/binary>>, Start, Nexts, Buf, Opt])
             end;

test/jsone_decode_tests.erl

@@ -151,8 +151,9 @@ decode_test_() ->
               ?assertMatch({error, {badarg, _}}, jsone_decode:decode(<<"\"\\uab\"">>)),  % too few hex characters
               ?assertMatch({error, {badarg, _}}, jsone_decode:decode(<<"\"\\ud848\"">>)), % high(first) surrogate only
               ?assertMatch({error, {badarg, _}}, jsone_decode:decode(<<"\"\\udc49\"">>)), % low(second) surrogate only
+              ?assertMatch({error, {badarg, _}}, jsone_decode:decode(<<"\"\\ud848\\u0061\"">>)), % missing low(second) surrogate
               ?assertMatch({error, {badarg, _}}, jsone_decode:decode(<<"\"\\udf0u\"">>)),
-              ?assertMatch({error, {badarg, _}}, jsone_decode:decode(<<"\"\\ud848\\u0061\"">>)) % missing low(second) surrogate
+              ?assertMatch({error, {badarg, _}}, jsone_decode:decode(<<"\"\\ud848\\udf0u\"">>))
       end},
 
      %% Arrays