corrupted ,v files break cvs-to-git mirror

[Jim Meyering]

This morning I noticed that my semi-automatic cvs-to-git
emacs repo-mirroring service got stuck in an infinite loop.
I tracked it down (through git-cvsimport and cvsps) to a corrupt ,v file:

    $ rlog /emacs/.state/cvsrepo/emacs/emacs/lisp/obsolete/swedish.el,v \
      |grep revision|head -25
    total revisions: 21;    selected revisions: 21
    revision 1.6
    revision 1.5
    revision 1.4
    revision 1.3
    revision 1.2
    revision 1.1   <<-- Huh?!?  This should be 1.13, not a duplicate of "1.1".
    revision 1.12
    revision 1.11
    revision 1.10
    revision 1.9
    revision 1.8
    revision 1.7
    revision 1.6
    revision 1.5
    revision 1.4
    revision 1.3
    revision 1.2
    revision 1.1
    Initial revision
    revision 1.8.14.5
    revision 1.8.14.4
    revision 1.8.14.3
    revision 1.8.14.2
    revision 1.8.14.1

I've never seen duplicate revision numbers like that before,
and I've been around the block a few time with cvs.
That seems like a serious problem.

For example, how will "cvs diff -r 1.6" work on this file, now?
Either way, it is guaranteed to be wrong some of the time.
If you tag the latest (1.6) version, which will it select?
If a tag for an older version of emacs pointed at the original
1.6 revision, does it still?  FYI, a couple of experiments suggest
that at least to rcsdiff (and probably cvs, too) the older shadowed
version numbers are not usable anymore.  E.g., rcsdiff -u -r1.11 -r1.12
on that ,v file gives an empty diff.  The 1.1 -> 1.2 diff selects the
most recent one, not the original.

Does anyone here have any idea how that happened?
FYI, here's the second "1.1" log entry, from "cvs log" output:
[What does "Moved" mean? ]

    ----------------------------
    revision 1.1
    date: 2005/08/23 20:05:32;  author: jhd;  state: Exp;
    Moved from international.  Old log:
    ;;; swedish.el --- miscellaneous functions for dealing with Swedish.
    ----------------------------
    revision 1.12
    date: 2005/07/04 17:22:27;  author: lute;  state: Exp;  lines: +2 -2
    Update FSF's address.
    ----------------------------

I hope it's easily fixed.