我是ruby语言的新手，我正在尝试运行一个现有的ruby on rails项目。尝试运行bundle install时失败，并出现以下错误。
Fetching mysql2 0.4.6
Installing mysql2 0.4.6 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
current directory: /home/vince/.rbenv/versions/2.7.6/lib/ruby/gems/2.7.0/gems/mysql2-0.4.6/ext/mysql2
/home/vince/.rbenv/versions/2.7.6/bin/ruby -I /home/vince/.rbenv/versions/2.7.6/lib/ruby/2.7.0 -r ./siteconf20221031-7332-kotkbi.rb extconf.rb
checking for rb_absint_size()... yes
checking for rb_absint_singlebit_p()... yes
checking for ruby/thread.h... yes
checking for rb_thread_call_without_gvl() in ruby/thread.h... yes
checking for rb_thread_blocking_region()... no
checking for rb_wait_for_single_fd()... yes
checking for rb_hash_dup()... yes
checking for rb_intern3()... yes
checking for rb_big_cmp()... yes
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.
Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/home/vince/.rbenv/versions/2.7.6/bin/$(RUBY_BASE_NAME)
--with-ruby-dir
--without-ruby-dir
--with-ruby-include
--without-ruby-include=${ruby-dir}/include
--with-ruby-lib
--without-ruby-lib=${ruby-dir}/lib
--with-mysql-dir
--without-mysql-dir
--with-mysql-include
--without-mysql-include=${mysql-dir}/include
--with-mysql-lib
--without-mysql-lib=${mysql-dir}/lib
--with-mysql-config
--without-mysql-config
--with-mysqlclient-dir
--without-mysqlclient-dir
--with-mysqlclient-include
--without-mysqlclient-include=${mysqlclient-dir}/include
--with-mysqlclient-lib
--without-mysqlclient-lib=${mysqlclient-dir}/lib
--with-mysqlclientlib
--without-mysqlclientlib
/home/vince/.rbenv/versions/2.7.6/lib/ruby/2.7.0/mkmf.rb:1050:in `block in find_library': undefined method `split' for nil:NilClass (NoMethodError)
from /home/vince/.rbenv/versions/2.7.6/lib/ruby/2.7.0/mkmf.rb:1050:in `collect'
from /home/vince/.rbenv/versions/2.7.6/lib/ruby/2.7.0/mkmf.rb:1050:in `find_library'
from extconf.rb:95:in `<main>'
To see why this extension failed to compile, please check the mkmf.log which can be found here:
/home/vince/.rbenv/versions/2.7.6/lib/ruby/gems/2.7.0/extensions/x86_64-linux/2.7.0/mysql2-0.4.6/mkmf.log
extconf failed, exit code 1
Gem files will remain installed in /home/vince/.rbenv/versions/2.7.6/lib/ruby/gems/2.7.0/gems/mysql2-0.4.6 for inspection.
Results logged to /home/vince/.rbenv/versions/2.7.6/lib/ruby/gems/2.7.0/extensions/x86_64-linux/2.7.0/mysql2-0.4.6/gem_make.out
An error occurred while installing mysql2 (0.4.6), and Bundler cannot continue.
Make sure that `gem install mysql2 -v '0.4.6' --source 'https://rubygems.org/'` succeeds before bundling.
In Gemfile:
mysql2
ruby版本是2.7.6、Rails5.0.7.2和EnvironmentUbuntu 20.04
有人知道问题的原因以及如何解决吗？我尝试过不同的堆栈溢出答案，但都没有帮助。
如果你需要更多的细节，请告诉我。
谢谢。
我不知道这是否是完美的答案，但它解决了我的问题。
更改gem文件中的mysql2版本如下
gem 'mysql2', '~>0.5.4'
然后运行bundle install解决了我的问题。
您需要首先通过brew 安装mysql
brew install mysql
然后尝试安装gem
gem install mysql2
成功后，请再次运行bundle install。