Funny 'git describe --contains' output

Hi,

In the Linux kernel tree, commit 0136db586c028f71e7cc21cc183064ff0d5919
is a bit "odd".

If I go to look to see what release it was in, I normally do:
	$ git describe --contains 0136db586c028f71e7cc21cc183064ff0d5919
	v3.6-rc1~59^2~56^2~76

However, it really showed up first in the 3.5-rc1 kernel release, as can
be seen by doing the following:
	$ git tag --contains 0136db586c028f71e7cc21cc183064ff0d5919
	v3.5
	v3.5-rc1
	v3.5-rc2
	v3.5-rc3
	v3.5-rc4
	v3.5-rc5
	v3.5-rc6
	v3.5-rc7
	v3.6-rc1
	v3.6-rc2
	v3.6-rc3

This commit ended up coming into Linus's tree in two different places,
both in 3.5-rc1 and in 3.6-rc1, through different merge requests, so it
seems to be tricky to figure out when it "first" went in.

Asking Linus about this, he tried the following:

	$ git name-rev --tags 0136db586c028f71e7cc21cc183064ff0d5919
	0136db586c028f71e7cc21cc183064ff0d5919 tags/v3.6-rc1~59^2~56^2~76
	$ git rev-list 0136db586c028f71e7cc21cc183064ff0d5919..v3.5-rc1 | wc
	  11415   11415  468015
	$ git rev-list 0136db586c028f71e7cc21cc183064ff0d5919..v3.4-rc1 | wc
	  0       0       0
	$ git rev-list 0136db586c028f71e7cc21cc183064ff0d5919..v3.6-rc1 | wc
	  22279   22279  913439

which shows that there are "less" commits to get from this commit to
v3.5-rc1 instead of v3.6-rc1, so something odd is going on here.

Any ideas?

I can reproduce this right now with git version 1.7.12.116.g31e0100

thanks,

greg k-h