Component 'json' of Ruby on Rails not working with Ruby 2.4.0

[Sega100500]

Install Ruby 2.4.0
In projects with RoR 3.2.xx, 4.2.xxx bundle install is fail:

Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

current directory: /home/ruby/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/json-1.8.3/ext/json/ext/generator

/home/ruby/.rbenv/versions/2.4.0/bin/ruby -r ./siteconf20161225-17221-ivjmjg.rb extconf.rb
creating Makefile

current directory: /home/ruby/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/json-1.8.3/ext/json/ext/generator
make "DESTDIR=" clean

current directory: /home/ruby/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/json-1.8.3/ext/json/ext/generator
make "DESTDIR="
compiling generator.c
generator.c: In function ‘generate_json’:
generator.c:861:25: error: ‘rb_cFixnum’ undeclared (first use in this function)
} else if (klass == rb_cFixnum) {
^
generator.c:861:25: note: each undeclared identifier is reported only once for each function it appears in
generator.c:863:25: error: ‘rb_cBignum’ undeclared (first use in this function)
} else if (klass == rb_cBignum) {
^
generator.c: At top level:
cc1: warning: unrecognized command line option "-Wno-self-assign"
cc1: warning: unrecognized command line option "-Wno-constant-logical-operand"
cc1: warning: unrecognized command line option "-Wno-parentheses-equality"
cc1: warning: unrecognized command line option "-Wno-tautological-compare"
Makefile:241: ошибка выполнения рецепта для цели «generator.o»
make: *** [generator.o] Ошибка 1

make failed, exit code 2

Gem files will remain installed in /home/ruby/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/json-1.8.3 for inspection.
Results logged to /home/ruby/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/extensions/x86_64-linux/2.4.0-static/json-1.8.3/gem_make.out

An error occurred while installing json (1.8.3), and Bundler cannot continue.
Make sure that gem install json -v '1.8.3' succeeds before bundling.

[Drenmi]

The JSON gem only supports the Integer unification in Ruby 2.4 starting from 2.0.0, and the Rails dependency is set to ~> 1.8, so you won't be able to run Rails 4.2 with Ruby 2.4 for now.

[Sega100500]

@Drenmi
gem json -v 1.8.5 is perfectly support it! On both RoR - 3.2.xx and 4.2.xx
Only with gem 'json', github: 'flori/json', branch: 'v1.8'
For many projects - is problem edit each Gemfile

Can still easier to fix this dependence in RoR?

[HarlemSquirrel]

It looks like this commit fixes it so we only have to wait for the next release.
47c4924

[Sega100500]

@rafaelfranca
When RoR 4.2.xx and 3.2.xx will be released to work with Ruby 2.4 ? When correct gem json will be released?

[rafaelfranca]

Rails 3.2 is not supported anymore so it may never be released to work with Ruby 2.4. About json gem I don't know.

[kapso]

How about RoR 4.2.x.x? Any plans for releasing a fix to support Ruby 2.4 ?

[matthewd]

See #27473 for a start on getting 4.2 working with 2.4.

[rickyc]

It's also failing for RoR 5.0.1.

[VarusSeptimus]

With Rails 5.0.1 & ruby 2.4.0, when doing bundle update (or gem install json -v '1.8.3') : Gem::Ext::BuildError: ERROR: Failed to build gem native extension. [...] error: ‘rb_cFixnum’ undeclared (first use in this function) [...] error: ‘rb_cBignum’ undeclared (first use in this function)

[VarusSeptimus]

Solved: I just commented out, in my Gemfile, the offending gem, sdoc (~> 0.4.0) which resolved to 0.4.0 and depended on json (~> 1.8)... and re-run bundle update all right...

[z0ph]

Same issue here with gem 'github-pages', trying to install json..

Solved my issue by downgrading to ruby 2.3 using this :

`brew install rbenv ruby-build

Add rbenv to bash so that it loads every time you open a terminal
echo 'if which rbenv > /dev/null; then eval "$(rbenv init -)"; fi' >> ~/.bash_profile
source ~/.bash_profile

Install Ruby
rbenv install 2.3.3
rbenv global 2.3.3
ruby -v`

from : https://gorails.com/setup/osx/10.12-sierra

[espen]

@rickyc try forcing json v2 in Gemfile: gem 'json', '~> 2'

[gowabash]

No dice on forcing json version

Bundler could not find compatible versions for gem "json":
  In Gemfile:
    json (~> 2)

    rails (= 4.2.7.1) was resolved to 4.2.7.1, which depends on
      activesupport (= 4.2.7.1) was resolved to 4.2.7.1, which depends on
        json (>= 1.7.7, ~> 1.7)```

[Drenmi]

gem json -v 1.8.5 is perfectly support it!

JSON 1.8.5 is not published to RubyGems.

[redox]

JSON 1.8.5 is not published to RubyGems.

It has just been published 👍

[nazreen]

@VarusSeptimus can you explain why commenting out sdoc does no harm to the project?

[evanrmurphy]

Thanks for the helpful comments. Editing Gemfile.lock and changing json's version from 1.8.3 to 1.8.5 fixed the issue for me. After that I could run bundle install without getting this error.

I got another error of course, but no longer this one. 😆