Per halostatue/diff-lcs#14, it is currently not possible to use the latest rspec-expectations (2.12.1) with diff-lcs 1.2 because that version of the rspec-expectations gem is '~> 1.1.3'. @petergoldstein provided rspec/rspec-expectations#200 (which I extend slightly with rspec/rspec-expectations#204) that should fix this, but a new release is required to allow @kevinansfield (and others) to use diff-lcs 1.2 with a modern release of rspec.
@myronmarston, thoughts on a point release? I'd also be game to plan for 2.13 soon if you give me a few days to wrap some things up in rspec-rails land.
We're planning to cut a release this weekend.
We released 2.13 earlier today.