mysql2 not working after upgrading mysql to 8

Question

I recently updated mysql to mysql8.0.4 from mysql5.7. I updated the mysql2 gem from 0.4.9 to 0.5.3 After that I starts getting the below error :

/Users/user/.rvm/gems/ruby-2.4.0@talent_now/gems/activerecord-5.1.4/lib/active_record/connection_adapters/connection_specification.rb:188:in `rescue in spec': 
Specified 'mysql2' for database adapter, but the gem is not loaded. Add `gem 'mysql2'` to your Gemfile (and ensure its version is at the minimum required by ActiveRecord). (Gem::LoadError)

I tried to downgrade mysql2 to 0.4.9 but then I got

/usr/local/Cellar/mysql/8.0.25_1/include/mysql/mysql.h:187:3: note: 'MYSQL_DEFAULT_AUTH' declared here
  MYSQL_DEFAULT_AUTH,
  ^
client.c:1315:38: error: use of undeclared identifier 'MYSQL_SECURE_AUTH'; did you mean 'MYSQL_DEFAULT_AUTH'?
  return _mysql_client_options(self, MYSQL_SECURE_AUTH, value);
                                     ^~~~~~~~~~~~~~~~~
                                     MYSQL_DEFAULT_AUTH
/usr/local/Cellar/mysql/8.0.25_1/include/mysql/mysql.h:187:3: note: 'MYSQL_DEFAULT_AUTH' declared here
  MYSQL_DEFAULT_AUTH,
  ^
2 errors generated.
make: *** [client.o] Error 1

make failed, exit code 2

I am using Rails5.1.4 in mac catalina

Answer 1

mysql2 0.5.x is not compatible with Rails5.1.4, so I updated Rails to 5.1.7 to make it work.

mysql2 0.5.x works with Rails / Active Record 4.2.11, 5.0.7, 5.1.6, and higher.

Above is mentioned on the mysql2 documentation.