Detached HEAD and "git log --all"

When discussing differences between concept and implementation of branches in Git and in Mercurial on StackOverflow[1] (abusing SO comment system a bit), Steve Losh[2] wrote that he was surprised by the fact that "git log --all" doesn't include commits made on detached HEAD.

While documentation clearly states:

  --all  Pretend as if all the refs in `$GIT_DIR/refs/` are listed
         on the command line as <commit>.

and HEAD is in `$GIT_DIR/HEAD`, which is outside `$GIT_DIR/refs/`, it is nevertheless a bit strange that "git log --all" doesn't list all (everything).

This is of course only an issue if we are on detached HEAD; I guess that semantics of `--all` option to git-log predates this feature.

[1] http://stackoverflow.com/questions/1598759/git-and-mercurial-compare-and-contrast/1599930#1599930 [2] http://stevelosh.com/blog/entry/2009/8/30/a-guide-to-branching-in-mercurial/