changing cjson dependency to another json library

[msva]

Hi there!
Original lua-cjson library seems to be abandoned by @mpx (he has no activity for more that year and all PRs are ignored), and the one in @openresty fork has no Lua5.2/5.3 compatibilty too (and also has no PRs for fixing another bugs).

So, how do you think about migrating to another json library?

[calio]

Do you have a particular one in mind?

[msva]

Actually, I've not benchmarked them, but https://github.com/harningt/luajson looks at least alive ;)
Although, I've anyway already sent a 5.2/5.3-compat PR to @openresty's cjson fork

[catwell]

@msva Why do you say cjson is not 5.3 compatible? There is a version in LuaRocks, called lua-cjson, which works well with 5.3 for me. All raven-lua tests pass using it.

That being said, luajson is almost completely compatible with cjson. All tests pass using it as well. Supporting it in addition to cjson would be a good idea, especially for environments where you cannot use C modules (luajson is pure Lua).

This can easily be done by replacing local json = require "cjson" by:

local json
do
   local ok
   ok, json = pcall(require, "cjson")
   if not ok then json = require "json" end
end

[msva]

@catwell I didn't say cjson isn't compatible with 5.3.
I only said that both cjson repos: original (@mpx) and @openresty one aren't (at the moment of that comment, at least). As for me, I using my own cjson fork. But since I maintaining lua packages ibn the distro, it'd be nice if there will be kinda "official" repo with "compatible" cjson ;)

[catwell]

Actually the one in LuaRocks is the one from @mpx and it is compatible with 5.3, except that it decodes integers to Lua floating point numbers, but that isn't such a big issue IMO.

[msva]

@catwell doubt it:

1. it is on "luarocks" account, but not on @mpx,
2. @mpx has neither commited in github repo nor released new releases on homepage for about 4 years.

So, there is definitely some fork.

@calio, btw, I've found https://github.com/bungle/lua-resty-libcjson (same on LR). Looks neat.

[catwell]

@msva Being on the "luarocks" account just means it wasn't adopted by its author since the move to moonrocks. The rockspec makes it clear it is not a fork.

The release is from March 2012 but it still works with Lua 5.3.

$ lua -v
Lua 5.3.1  Copyright (C) 1994-2015 Lua.org, PUC-Rio
$ luarocks list | grep -A1 cjson
lua-cjson
   2.1.0-1 (installed) - /usr/lib/luarocks/rocks-5.3
$ make
Loaded testsuite with 12 tests in 3 testcases.

[ERROR] Failed to send to Sentry:   connection refused      {"level":"error","message":"IF YOU ARE READING THIS IT IS CORRECT; THIS TEST SHOULD GENERATE AN ERROR.","server_name":"undefined","timestamp":"2015-12-09T08:32:33","event_id":"d9d72cb5635c41ad8b239b598efcf148","culprit":"tests\/test_exceptions.lua:17","logger":"root","platform":"lua"}
    .[ERROR]    Failed to send to Sentry:   connection refused      {"level":"error","timestamp":"2015-12-09T08:32:33","culprit":"error","platform":"lua","event_id":"111e94a4a18f4e9a8c5cff848028d291","message":"tests\/test_exceptions.lua:28: bad","exception":[{"stacktrace":{"frames":[{"lineno":-1,"filename":"[C]"},{"lineno":11,"filename":"stdin"},{"lineno":540,"filename":"\/usr\/share\/lua\/5.3\/lunit.lua"},{"function":"runtest","lineno":522,"filename":"\/usr\/share\/lua\/5.3\/lunit.lua"},{"function":"callit","lineno":504,"filename":"\/usr\/share\/lua\/5.3\/lunit.lua"},{"function":"mypcall","lineno":108,"filename":"\/usr\/share\/lua\/5.3\/lunit.lua"},{"function":"xpcall","lineno":-1,"filename":"[C]"},{"lineno":28,"filename":"tests\/test_exceptions.lua"},{"function":"xpcall","lineno":-1,"filename":"[C]"},{"lineno":28,"filename":"tests\/test_exceptions.lua"},{"function":"error","lineno":-1,"filename":"[C]"}]},"value":"tests\/test_exceptions.lua:28: bad"}],"server_name":"undefined","logger":"root"}
...........

60 Assertions checked.

Testsuite finished (12 passed, 0 failed, 0 errors).

[msva]

Talking about original message in the issue, I said "@mpx one is abandoned, and @openresty fork - has no 5.2/5.3 compatibility) :)

// btw, by default, CMake there, in @mpx repo, has issues with finding (and linking against) luajit. Which I (kinda) fixed.

[catwell]

The OpenResty fork has the same 5.3 compatibility as the @mpx version: it just does not have special code for integers and considers them as doubles. So it works exactly the same as with 5.2.

The only differences between the OpenResty fork and the original are:

• an option to encode empty JSON tables as arrays which is not used by raven-lua;
• better precision when encoding very large numbers (more than 14 decimal places).

If the mpx version is abandonned we will just replace it with the OpenResty version in LuaRocks. Also it looks like OpenResty will merge your PR.