MySQL Improperly Configured: The Problem with Relative Paths

When running python manage.py runserver in Django, you may encounter the following error:

ImproperlyConfigured: Error loading MySQLdb module: dlopen(/Library/Python/2.7/site-packages/_mysql.so, 2): Library not loaded: libmysqlclient.18.dylib
  Referenced from: /Library/Python/2.7/site-packages/_mysql.so
  Reason: unsafe use of relative rpath libmysqlclient.18.dylib in /Library/Python/2.7/site-packages/_mysql.so with restricted binary

The Cause

This error occurs due to Apple's implementation of System Integrity Protection in OS X El Capitan (10.11). This prevents programs in protected locations like /usr from accessing shared libraries using relative references.

In this case, the shared library _mysql.so contains a relative reference to libmysqlclient.18.dylib.

The Solution

To resolve this issue, you will need to force _mysql.so to use an absolute reference to libmysqlclient.18.dylib. This can be achieved using the install_name_tool utility.

Steps to Resolve the Issue

1. Ensure that libmysqlclient.18.dylib is located in /usr/local/mysql/lib/.
2. Run the following command in Terminal:

sudo install_name_tool -change libmysqlclient.18.dylib \
  /usr/local/mysql/lib/libmysqlclient.18.dylib \
  /Library/Python/2.7/site-packages/_mysql.so

This command will update the shared library reference in _mysql.so to use the absolute path to libmysqlclient.18.dylib.

After running this command, you should be able to successfully run python manage.py runserver without the MySQL configuration error.