Mojang/LegacyLauncher — pull request #3 by Mumfrey (2013-10-04 11:33:31+00:00)
Title: Prevent an infinite loop with duplicated tweakers

The sanity check for duplicated tweakers works and does correctly skip instancing the tweaker, however because the tweak is not removed from the tweak class list it creates an infinite loop.

This can be easily tested by just specifying the same tweak class more than once on the command line.