Here is a list of what we are loosing when moving to GitHub:

• no private branches (where we'll put our repository for papers?)

• no private wiki pages (where we'll put our todo list and referee comments?)

• command line unfriendly behavior of the GitHub download links for .zip and .tar.gz files
  • here is how it works currently:

    wget http://cp3.irmp.ucl.ac.be/downloads/Delphes-3.1.2.tar.gz
    

  • here is how it works with GitHub (command is almost twice longer and with additional parameters):

    wget --no-check-certificate https://github.com/delphes/delphes/archive/master.tar.gz -O delphes-master.tar.gz
    

• no search in wiki pages (github proposes to do it from command line using grep)

• less functional code browser (for example, no way to compare old and new versions of the same file, and yes, I regularly use this functionality)

• no way to adapt to our needs the interface of the code browser, wiki pages and issue tracker (for example, currently it's difficult to switch from code browser back to documentation)

• some information (formatting, dates, users) will be lost after migration of the tickets from trac to github.

• backup of github code repositories is more difficult (needs manual intervention for any new repository)

• backup of issues/tickets is even more difficult

• restore from backup is not clear at all

Possible alternatives:

• Trac with local Subversion repository and mirrors on GitHub, LaunchPad and BitBucket as it's done by the Trac developers: ​http://trac.edgewall.org/ticket/9235

• Trac with local Git repository and mirrors

• local GitLab with local Git repository and mirrors