捆绑安装失败，原因是：Gem::Ext::BuildError: ERROR: Failed to build gem native extension

Question

我是 ruby 语言的新手，我正在尝试运行现有的 ruby on Rails 项目。 在尝试运行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版本为2.7.6 ，Rails 5.0.7.2 ，环境Ubuntu 20.04

有谁知道问题的原因以及如何解决？ 我尝试了不同的堆栈溢出答案，但都没有帮助。

如果您需要任何进一步的详细信息，请告诉我。

谢谢你。

Answer 1

您需要先通过 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 。

Answer 2

我不知道这是否是完美的答案，但是，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。