uninitialized constant Mysql2::Client::SECURE_CONNECTION

[JohnMerlino1]

I ran the following command on OSX 10.9.5:

brew update && brew upgrade && brew install imagemagick

Since that point, rails server and rails console raises errors.

Below is the first few lines of the error:

Users/donato/.rvm/gems/ruby-2.1.2@core/gems/mysql2-0.3.16/lib/mysql2/client.rb:12:in <class:Client>': uninitialized constant Mysql2::Client::SECURE_CONNECTION (NameError) from /Users/donato/.rvm/gems/ruby-2.1.2@core/gems/mysql2-0.3.16/lib/mysql2/client.rb:2:inmodule:Mysql2'
from /Users/donato/.rvm/gems/ruby-2.1.2@core/gems/mysql2-0.3.16/lib/mysql2/client.rb:1:in <top (required)>' from /Users/donato/.rvm/gems/ruby-2.1.2@core/gems/mysql2-0.3.16/lib/mysql2.rb:10:inrequire'
from /Users/donato/.rvm/gems/ruby-2.1.2@core/gems/mysql2-0.3.16/lib/mysql2.rb:10:in `<top (required)>'

This is the mysql gem I am using (which was working fine until the brew update):
gem 'mysql2', '0.3.16'

How can I resolve this?

[jeremy]

Duplicate of #603.

(When you did a brew update, you upgraded MySQL. Now upgrade the mysql2 library to support it.)

[JohnMerlino1]

It seems the issue went away when upgrading the mysql2 gem to 0.3.18. When I updated it to latest version, I got a gemload error, and I assume the latest version is only compatible with Rails 5, whereas I am using Rails 4:

http://stackoverflow.com/questions/32457657/rails-4-gemloaderror-specified-mysql2-for-database-adapter-but-the-gem-i

[sodabrew]

This particular issue for supporting MySQL 5.7 was added in 0.3.17 and higher. As for mysql2 0.3.x / 0.4.x, here's the compatibility table for Rails and mysql2 versions: https://github.com/brianmario/mysql2/blob/master/README.md#compatibility

[deepakmahakale]

Changing the version to ~> 0.3.21 fixed it for me

gem 'mysql2', '~> 0.3.21'

[kroim]

gem 'mysql2', '~> 0.3.21'

This worked for me as well.
rails = 3.1.3, ruby = 1.9.3.p330

[Kulgar]

And here too
rails = 3.2.12, ruby = 1.8.7 (yeah, very old project...)

[deepakmahakale]

@kroim @Kulgar
You gotta upgrade those apps 😄

[Kulgar]

@deepakmahakale : yeah... I've just got that one into my hands, I even didn't know it was using a ruby that old until today... :-/