Error installing json Ruby gem - ruby-on-rails

Question

I'm running gem install json -v '1.8.1' however I get this error..
gem install json -v '1.8.1'
Building native extensions. This could take a while...
ERROR: Error installing json:
ERROR: Failed to build gem native extension.
current directory: /Users/johnwilliamson/.rvm/gems/ruby-2.4.1/gems/json-1.8.1/ext/json/ext/generator
/Users/johnwilliamson/.rvm/rubies/ruby-2.4.1/bin/ruby -r ./siteconf20170412-72871-wada1h.rb extconf.rb
creating Makefile
current directory: /Users/johnwilliamson/.rvm/gems/ruby-2.4.1/gems/json-1.8.1/ext/json/ext/generator
make "DESTDIR=" clean
current directory: /Users/johnwilliamson/.rvm/gems/ruby-2.4.1/gems/json-1.8.1/ext/json/ext/generator
make "DESTDIR="
compiling generator.c
In file included from generator.c:1:
./../fbuffer/fbuffer.h:175:47: error: too few arguments provided to function-like macro invocation
VALUE result = rb_str_new(FBUFFER_PAIR(fb));
^
/Users/johnwilliamson/.rvm/rubies/ruby-2.4.1/include/ruby-2.4.0/ruby/intern.h:795:9: note: macro 'rb_str_new' defined here
#define rb_str_new(str, len) RB_GNUC_EXTENSION_BLOCK( \
^
In file included from generator.c:1:
./../fbuffer/fbuffer.h:175:11: warning: incompatible pointer to integer conversion initializing 'VALUE' (aka 'unsigned long') with an expression of type 'VALUE (const char *, long)' (aka 'unsigned long (const char *, long)') [-Wint-conversion]
VALUE result = rb_str_new(FBUFFER_PAIR(fb));
^ ~~~~~~~~~~
generator.c:840:25: error: use of undeclared identifier 'rb_cFixnum'
} else if (klass == rb_cFixnum) {
^
generator.c:842:25: error: use of undeclared identifier 'rb_cBignum'
} else if (klass == rb_cBignum) {
^
1 warning and 3 errors generated.
make: *** [generator.o] Error 1
make failed, exit code 2
Gem files will remain installed in /Users/johnwilliamson/.rvm/gems/ruby-2.4.1/gems/json-1.8.1 for inspection.
Results logged to /Users/johnwilliamson/.rvm/gems/ruby-2.4.1/extensions/x86_64-darwin-16/2.4.0/json-1.8.1/gem_make.out
When I run just gem install json it installs fine taking me over version 2 however I'm trying to install this https://github.com/peatio/peatio and it wants that version specifically.
Any other ideas?

Answer 1

Finding and updating the gem that is pulling in the JSON gem should work. However, another thing that worked for me was to update the version of JSON being installed.
bundle update json
This worked because it updated JSON to version 1.8.6 which is compatible with newer Rubies.

Answer 2

This seems to be a common issue with the json 1.8.1 gem. You can use a different version of json if you are declaring it explicitly, but in some cases, json 1.8.1 is a cascading dependency. For instance, you may see something like
In Gemfile:
rails was resolved to 4.1.5, which depends on
actionmailer was resolved to 4.1.5, which depends on
actionpack was resolved to 4.1.5, which depends on
actionview was resolved to 4.1.5, which depends on
activesupport was resolved to 4.1.5, which depends on
json
In this case, you just need to change the top level gem (in this case rails) to a different version. 4.2.6 works.

Answer 3

The issue is arise due to you are not in proper directory. Please go to your rails directory folder first then run this command like this:
rails#rails:~/rails_project/btc$ gem install json -v '1.8.1'
Then its work fine.