Drush from GitHub stopped working I have a Github clone of drush that has been working since it moved there.  I did a git pull this morning, and am now getting errors:


  $ drush
  
  Warning: require(/home/mpd/drush/vendor/autoload.php): failed to open
  stream: No such file or directory in
  /home/mpd/drush/includes/bootstrap.inc on line 1007
  
  Fatal error: require(): Failed opening required
  '/home/mpd/drush/vendor/autoload.php' (include_path='.:') in
  /home/mpd/drush/includes/bootstrap.inc on line 1007


How can I fix this?
Drush now uses composer for managing external libraries.  You can read about this in the GitHub issue.

If you don't have composer installed, you can follow the instructions on its project page.  Under Linux or OSX, you can do

$ curl -sS https://getcomposer.org/installer | php
$ mv composer.phar /usr/local/bin/composer


which will install it globally.

Once you have done this, you can

$ cd /path/to/your/git/clone/of/drush
$ composer install


This will download all of the external depencencies, and drush should start working.

See the drush project page for details.