mysql - 安装gem报错

Question

１．相应的环境：　
　　　ubuntu12.04 ruby 2.4
2.通过　

bundle install --deployment --without development test postgres aws

安装gem的时候报错：

　

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

current directory:
/home/git/gitlab/vendor/bundle/ruby/2.4.0/gems/json-1.8.1/ext/json/ext/generator
/usr/local/bin/ruby -r ./siteconf20170122-2448-oz1rn0.rb extconf.rb
creating Makefile

current directory:
/home/git/gitlab/vendor/bundle/ruby/2.4.0/gems/json-1.8.1/ext/json/ext/generator
make "DESTDIR=" clean

current directory:
/home/git/gitlab/vendor/bundle/ruby/2.4.0/gems/json-1.8.1/ext/json/ext/generator
make "DESTDIR=" compiling generator.c In file included from
generator.c:1:0: ../fbuffer/fbuffer.h: In function 'fbuffer_to_s':
../fbuffer/fbuffer.h:175:47: error: macro "rb_str_new" requires 2
arguments, but only 1 given ../fbuffer/fbuffer.h:175:20: warning:
initialization makes integer from pointer without a cast [enabled by
default] generator.c: In function 'generate_json': generator.c:840:25:
error: 'rb_cFixnum' undeclared (first use in this function)
generator.c:840:25: note: each undeclared identifier is reported only
once for each function it appears in generator.c:842:25: error:
'rb_cBignum' undeclared (first use in this function) generator.c: At
top level: cc1: warning: unrecognized command line option
"-Wno-self-assign" [enabled by default] cc1: warning: unrecognized
command line option "-Wno-constant-logical-operand" [enabled by
default] cc1: warning: unrecognized command line option
"-Wno-parentheses-equality" [enabled by default] cc1: warning:
unrecognized command line option "-Wno-tautological-compare" [enabled
by default] make: * [generator.o] Error 1

make failed, exit code 2

Gem files will remain installed in
/home/git/gitlab/vendor/bundle/ruby/2.4.0/gems/json-1.8.1 for

1. Results logged to
   /home/git/gitlab/vendor/bundle/ruby/2.4.0/extensions/x86-linux/2.4.0-static/json-1.8.1/gem_make.out

An error occurred while installing json (1.8.1), and Bundler cannot

1. Make sure that gem install json -v '1.8.1' succeeds before　bundling.

但是看到Make sure that gem install json -v '1.8.1' succeeds before　bundling.

于是我就手动安装了gem install json -v '1.8.1' ,
依然报错：

Building native extensions.  This could take a while...
ERROR:  Error installing json:
    ERROR: Failed to build gem native extension.

    current directory: /usr/local/lib/ruby/gems/2.4.0/gems/json-1.8.1/ext/json/ext/generator
/usr/local/bin/ruby -r ./siteconf20170122-3475-aueo31.rb extconf.rb
creating Makefile

current directory: /usr/local/lib/ruby/gems/2.4.0/gems/json-1.8.1/ext/json/ext/generator
make "DESTDIR=" clean

current directory: /usr/local/lib/ruby/gems/2.4.0/gems/json-1.8.1/ext/json/ext/generator
make "DESTDIR="
compiling generator.c
In file included from generator.c:1:0:
../fbuffer/fbuffer.h: In function 'fbuffer_to_s':
../fbuffer/fbuffer.h:175:47: error: macro "rb_str_new" requires 2 arguments, but only 1 given
../fbuffer/fbuffer.h:175:20: warning: initialization makes integer from pointer without a cast [enabled by default]
generator.c: In function 'generate_json':
generator.c:840:25: error: 'rb_cFixnum' undeclared (first use in this function)
generator.c:840:25: note: each undeclared identifier is reported only once for each function it appears in
generator.c:842:25: error: 'rb_cBignum' undeclared (first use in this function)
generator.c: At top level:
cc1: warning: unrecognized command line option "-Wno-self-assign" [enabled by default]
cc1: warning: unrecognized command line option "-Wno-constant-logical-operand" [enabled by default]
cc1: warning: unrecognized command line option "-Wno-parentheses-equality" [enabled by default]
cc1: warning: unrecognized command line option "-Wno-tautological-compare" [enabled by default]
make: *** [generator.o] Error 1

make failed, exit code 2

Gem files will remain installed in /usr/local/lib/ruby/gems/2.4.0/gems/json-1.8.1 for inspection.
Results logged to /usr/local/lib/ruby/gems/2.4.0/extensions/x86-linux/2.4.0-static/json-1.8.1/gem_make.out

本人并不太了解ruby，gem,我只是安装依赖ruby的软件时候遇到的。请哪位大神帮忙看一下，该问题应该怎么解决？还有讲讲ruby , gem , ruby-rails,bundle之间的关系！
谢谢！

Answer 1

json-1.8.1 与 ruby-2.4.0 不兼容，想要顺利安装，可以尝试一下下面两个办法：

1. 降低 Ruby 的版本。查了一下，1.8.1 已经很老了，与 2.2.x 版本不兼容，需要降到 2.1.x 版本。

2. 升级 json 到 1.8.5 版本。执行 bundle update json，然后 bundle install。因为不知道你的 Gemfile 是怎么写的，无法确定有没有明确依赖 1.8.1 版本。所以这个方法不一定成功。

Ruby 是语言。
gem 是一组 Ruby 程序，类似于「包」的概念。
RubyGems 是 Ruby 的包管理器，用来管理和安装 gems 的。
bundle 是用来管理一个项目的 gems 的，确保能够正确地安装项目依赖，确保能够运行正确的包。