git checkout --orphan skips reflogging

In short, git checkout --orphan doesn't write
HEAD_sha1 -> 00000
entry to logs/HEAD, while git-comit will write
00000 -> new_orphan_HEAD_sha1
entry. And then reflog backward walk will stop on 000 -> entry and
won't see earlier history.

How to reproduce:
$ git init test && cd test
$ git commit -m A --allow-empty
$ git checkout --orphan topic
$ git commit -m B --allow-empty
$ git log -g --oneline HEAD
some_sha1 HEAD@{0}: commit (initial): B
# oops, where are my old HEADs?
$ cat .git/logs/HEAD
000.. another_sha1 ... commit (initial): A
000.. some_sha1 ... commit (initial): B
# phew, at least I can find them by hand

Isn't  it also a bug in reflog walking that we rely on each old_sha1
being new_sha1 of a previous entry?