Odd results with git-describe

Hi,

with rust's git repo -- located at https://github.com/rust-lang/rust.git -- we see odd results from git-describe for the latest tag.

$ git rev-parse HEAD 795f6ae829ab1bfd72394a5da9096e2717ec0f62

$ git describe  --debug
searching to describe HEAD
finished search at 7140d7c52bdf55daf0b978a19706d20c3bf7ee92
 annotated       3627 0.10
 annotated       5929 0.9
 annotated       8581 0.8
 annotated      11686 0.7
 annotated      14540 0.6
 annotated      15230 0.11.0
traversed 15232 commits
0.10-3627-g795f6ae

Somehow it reports that 0.11.0 is missing tons of commits that are in HEAD. rev-list disagrees with this:

$ git rev-list 0.11.0.. | wc -l 1155

The `SEARCH STRATEGY` section of the manpage says that the commit numbers for describe and rev-list should match, which is not the case here.

Björn