Comment 6 for bug 292557

@SoloTurn:

Well, for a concrete example: Mercurial does not (and will not) version directories as first class objects. Bazaar does. Therefore, Bazaar can represent an empty directory's appearance in history, while Mercurial cannot. Whether most projects need this ability or not is not the point -- the point is that Mercurial cannot represent a history that Bazaar can, yet the reverse is not true. (Well, at least for this case. I don't know of any case where Mercurial can represent a history that Bazaar cannot, but I haven't personally studied that question in enough detail to claim it with certainty. However, I think it is more likely true than not; counterexamples welcome.)

Something similar is true about first-class renames, w.r.t. both Mercurial and Git, I believe.

So AFAIK, you *can* actually lose some information if you use Git or Mercurial as a client against a Bazaar repository. (Again, I'm making these claims based on shallow research, and welcome opinions more expert than mine.)

@André Klitzing:

Yes, you've got it right. And I've linked to this discussion from the FAQ item now.