Merge branch 'rn/sparse-describe'

"git describe --dirty" learns to work better with sparse-index.

* rn/sparse-describe:
  describe: enable sparse index for describe

diff --cc builtin/describe.c
Simple merge

diff --cc t/perf/p2000-sparse-operations.sh
index f7bdba90c55cac4368774dd5f0afa7814b35a9f3,db7887470f9c6cfff55b19533a87d3d560a18ef1..60d1de0662ac4842f0163d05366b20a62524f3db
--- 1/t/perf/p2000-sparse-operations.sh
--- 2/t/perf/p2000-sparse-operations.sh
+++ b/t/perf/p2000-sparse-operations.sh
@@@ -124,7 -125,8 +125,9 @@@ test_perf_on_all git read-tree -mu HEA
  test_perf_on_all git checkout-index -f --all
  test_perf_on_all git update-index --add --remove $SPARSE_CONE/a
  test_perf_on_all "git rm -f $SPARSE_CONE/a && git checkout HEAD -- $SPARSE_CONE/a"
 -test_perf_on_all git grep --cached --sparse bogus -- "f2/f1/f1/*"
 +test_perf_on_all git grep --cached bogus -- "f2/f1/f1/*"
 +test_perf_on_all git write-tree
+ test_perf_on_all git describe --dirty
+ test_perf_on_all 'echo >>new && git describe --dirty'
  
  test_done

diff --cc t/t1092-sparse-checkout-compatibility.sh
Simple merge