In my svn config I have colordiff setup

~/.subversion/config --> "diff-cmd = colordiff"

But this breaks QtCreator diff display, showing escape characters. eg.

— snip
Index: source/blender/bmesh/intern/bmesh_walkers_impl.c
===================================================================
--- source/blender/bmesh/intern/bmesh_walkers_impl.c (revision 56780)
+++ source/blender/bmesh/intern/bmesh_walkers_impl.c (working copy)
— snip

QtCreator should pass --diff-cmd=diff to svn, or at the very least, allow the diff command to be set in the preferences.