[1.7.9] usage regression when merging annotated tag objects

I recently started using git 1.7.9.  Earlier today GregKH released a stable kernel update and I tried my tried and true procedure using 'git merge --ff-only v3.2.3'.  I was a bit surprised with the results.

There are two tags I am toying with...

69bade0 is v3.2.3 3499d64 is v3.2.2

And here is where we start...

$ git describe v3.2.2

$ git merge-base v3.2.2 v3.2.3 | xargs git describe v3.2.2

(it is thus eligible for a fast-forward)

Finally, the strangeness...

$ git merge --ff-only v3.2.3 fatal: Not possible to fast-forward, aborting.

$ git merge --ff-only v3.2.3~ Updating 3499d64..7b171c5 Fast-forward ...

$ git merge --ff-only v3.2.3 fatal: Not possible to fast-forward, aborting.

After talking to Junio, he pointed out that "merging tag objects gained new meanings in 1.7.9".

I am not sure if my confusion will be shared by others and if --ff-only needs a clarification.  Perhaps --ff-only should just continue to work as it did before, and fast-forward from tag to tag.

Cheers, -Bart