On Windows, why does Trac not display diffs?
Note: this problem concerns old version of Subversion and Trac, and can probably be deleted from the FAQ. The tree diff functionality provided by the subversion python bindings use an external diff_ command. On UNIX-like systems, diff is usually installed already, so this wasn’t an issue there. Installing diffutils should solve the problem. After installing diffutils, you will need to add the path to the diff executable to the Windows PATH environment variable and reboot the machine.