mysql2 gem fails to compile with MySQL 5.6.12 on OS X with Homebrew

Question

I updated all the packages I installed with Homebrew. MySQL got upgraded to 5.6.12 (from 5.5.27 or so):

$ mysql --version
mysql  Ver 14.14 Distrib 5.6.12, for osx10.8 (x86_64) using  EditLine wrapper

and now the mysql2 gem doesn't compile anymore:

$ gem install mysql2
Building native extensions.  This could take a while...
ERROR:  Error installing mysql2:
    ERROR: Failed to build gem native extension.

        /Users/pupeno/.rvm/rubies/ruby-1.9.3-p429-perf/bin/ruby extconf.rb
checking for rb_thread_blocking_region()... yes
checking for rb_wait_for_single_fd()... yes
checking for mysql.h... no
checking for mysql/mysql.h... no
-----
mysql.h is missing.  please check your installation of mysql and try again.
-----
*** 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
    --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=/Users/pupeno/.rvm/rubies/ruby-1.9.3-p429-perf/bin/ruby
    --with-mysql-config
    --without-mysql-config

The file mysql.h is present in /usr/local/Cellar/mysql/5.6.12/include/mysql.h. Any ideas what's going on?

The file mysql.h doesn't appear in /usr/local because the symlink seems to go deeper than it should:

$ ls -la /usr/local/include/mysql
lrwxr-xr-x  1 pupeno  admin  36 21 Jun 15:18 /usr/local/include/mysql@ -> ../Cellar/mysql/5.6.12/include/mysql

instead of

/usr/local/Cellar/mysql/5.6.12/include

Having said that, I manually fixed the symlink and the compilation still failed. So I'm stuck.

Answer 1

I had the same problem, I managed to fix it. I did a lot of things, and I don't know for sure what it was, but going to MySQL 5.6.10 seems to have worked.

Uninstall MySQL 5.6.12:

brew unlink mysql
brew uninstall mysql

Go to the homebrew directory:

cd /usr/local

Go to version 5.6.10 (you can find a list of versions by running brew versions mysql:

git checkout 48f7e86 Library/Formula/mysql.rb

Then install mysql again:

brew install mysql

And now gem install mysql2 works for me.

I've also installed mysql from source (brew install mysql --build-from-source), but that didn't solve it, but might be part of the solution.