[cvsnt] "cvs unedit" and renaming files

[Gareth McCaughan]

One of my colleagues came to me with a puzzling error.
He was trying to do a "cvs unedit" using TortoiseCVS,
and getting a message along the lines of "[unedit aborted]
cannot rename CVS/Base/foo to foo: File exists".

After a bit of poking about, it turns out that

  - this message comes from CVSNT
  - the "File exists" bit of it comes from Windows'
    strerror function
  - it's a lie: although Microsoft's documentation
    claims that rename() always fails when the new
    filename is that of an existing file, that's
    false and there's usually a different problem
  - in this instance the real problem was that the
    file in question was in use (i.e., someone else
    had it open)

This is a bit sad usability-wise; my colleague was
deeply confused, and so was I (more so once I'd read
the source code and MS' documentation, according to
which a "cvs unedit" should *never* work!). Of course
there's no prospect of getting strerror to return
anything more helpful; but might it be worth considering
an ugly-but-practical measure such as checking errno
or even the return value from strerror (ugh!) and
conditionally appending a note along the lines of

  | (This may actually indicate that the file is
  | protected or currently in use.)

?

-- 
Gareth McCaughan