bundle install で An error occurred while installing mysql2 (0.5.3), and Bundler cannot continue. エラーが発生したときの解決方法をご紹介します。

背景 An error occurred while installing mysql2 (0.5.3), and Bundler cannot continue.

bundle install すると An error occurred while installing mysql2 (0.5.3), and Bundler cannot continue. というエラーが出て gem install mysql2 -v ‘0.5.3’ —source ‘https://rubygems.org/’ しても解決しなくて困ったお話です。

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

    current directory: /Users/your_name/.rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/mysql2-0.5.3/ext/mysql2
/Users/your_name/.rbenv/versions/3.0.2/bin/ruby -I /Users/your_name/.rbenv/versions/3.0.2/lib/ruby/3.0.0 -r ./siteconf20211006-6349-579dvn.rb extconf.rb
checking for rb_absint_size()... yes
checking for rb_absint_singlebit_p()... yes
checking for rb_wait_for_single_fd()... yes
-----
Using mysql_config at /usr/local/bin/mysql_config
-----
checking for mysql.h... yes
checking for errmsg.h... yes
checking for SSL_MODE_DISABLED in mysql.h... yes
checking for SSL_MODE_PREFERRED in mysql.h... yes
checking for SSL_MODE_REQUIRED in mysql.h... yes
checking for SSL_MODE_VERIFY_CA in mysql.h... yes
checking for SSL_MODE_VERIFY_IDENTITY in mysql.h... yes
checking for MYSQL.net.vio in mysql.h... yes
checking for MYSQL.net.pvio in mysql.h... no
checking for MYSQL_ENABLE_CLEARTEXT_PLUGIN in mysql.h... yes
checking for SERVER_QUERY_NO_GOOD_INDEX_USED in mysql.h... yes
checking for SERVER_QUERY_NO_INDEX_USED in mysql.h... yes
checking for SERVER_QUERY_WAS_SLOW in mysql.h... yes
checking for MYSQL_OPTION_MULTI_STATEMENTS_ON in mysql.h... yes
checking for MYSQL_OPTION_MULTI_STATEMENTS_OFF in mysql.h... yes
checking for my_bool in mysql.h... no
-----
Don't know how to set rpath on your system, if MySQL libraries are not in path mysql2 may not load
-----
-----
Setting libpath to /usr/local/Cellar/mysql/8.0.26/lib
-----
creating Makefile

current directory: /Users/your_name/.rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/mysql2-0.5.3/ext/mysql2
make DESTDIR\\= clean

current directory: /Users/your_name/.rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/mysql2-0.5.3/ext/mysql2
make DESTDIR\\=
compiling client.c
client.c:787:14: warning: incompatible pointer types passing 'VALUE (void *)' (aka 'unsigned long (void *)') to parameter of type 'VALUE (*)(VALUE)' (aka 'unsigned long
(*)(unsigned long)') [-Wincompatible-pointer-types]
  rb_rescue2(do_send_query, (VALUE)&args, disconnect_and_raise, self, rb_eException, (VALUE)0);
             ^~~~~~~~~~~~~
/Users/your_name/.rbenv/versions/3.0.2/include/ruby-3.0.0/ruby/internal/iterator.h:51:25: note: passing argument to parameter here
VALUE rb_rescue2(VALUE(*)(VALUE),VALUE,VALUE(*)(VALUE,VALUE),VALUE,...);
                        ^
client.c:795:16: warning: incompatible pointer types passing 'VALUE (void *)' (aka 'unsigned long (void *)') to parameter of type 'VALUE (*)(VALUE)' (aka 'unsigned long
(*)(unsigned long)') [-Wincompatible-pointer-types]
    rb_rescue2(do_query, (VALUE)&async_args, disconnect_and_raise, self, rb_eException, (VALUE)0);
               ^~~~~~~~
/Users/your_name/.rbenv/versions/3.0.2/include/ruby-3.0.0/ruby/internal/iterator.h:51:25: note: passing argument to parameter here
VALUE rb_rescue2(VALUE(*)(VALUE),VALUE,VALUE(*)(VALUE,VALUE),VALUE,...);
                        ^
2 warnings generated.
compiling infile.c
compiling mysql2_ext.c
compiling result.c
compiling statement.c
linking shared-object mysql2/mysql2.bundle
ld: library not found for -lssl
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [mysql2.bundle] Error 1

make failed, exit code 2

Gem files will remain installed in /Users/your_name/.rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/mysql2-0.5.3 for inspection.
Results logged to /Users/your_name/.rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/extensions/x86_64-darwin-19/3.0.0/mysql2-0.5.3/gem_make.out

An error occurred while installing mysql2 (0.5.3), and Bundler cannot continue.
Make sure that `gem install mysql2 -v '0.5.3' --source 'https://rubygems.org/'` succeeds before bundling.

In Gemfile:
  spree_dev_tools was resolved to 0.1.10, which depends on
    mysql2

解決方法 bundle config --local build.mysql2 "--with-ldflags=-L/usr/local/opt/openssl/lib"

bundle config --local build.mysql2 "--with-ldflags=-L/usr/local/opt/openssl/lib"
bundle install

以上、bundle install で mysql2 をインストールできないエラーを解決した、現場からお送りしました。

参考情報

• bundle installでmysql2がエラーになる件 - Qiita