why are these files being transfered

[Harry Putnam]

jw schultz <jw at pegasys.ws> writes:

> Hmm, -a == -rlptgoD  could it be that the timestamp, owner,
> group or perms differ?

No, thats not it (at least not all of it) I see the same behavior with
rsync -rCv.  Only thing that comes close is `-rCcv'.  Even that
transfers a few files that diff sees no difference in.

Is there a major difference between differences as reported by diff
and what rsync does?  If we ignore timestamp, permissions and
ownership.  And diff finds no difference between two files.  And I
even went so far as to run md5sum on a couple.  With all that same
ness, why would rsync mess with it?

Seems one should not need the -c flag if diff reports no difference,
and the rsync commmand line is -r only.

But look at this:

  reader $ ls -l buf.t/UPDATE base.t/UPDATE 
  -rw-rw-r--  1 reader   reader   2589 May 30 18:06 base.t/UPDATE
  -rw-r--r--  1 reader   reader   2589 May 29 14:21 buf.t/UPDATE

  reader $ diff buf.t/UPDATE base.t/UPDATE 
   <nothing>

 md5sum buf.t/UPDATE base.t/UPDATE 
  050a08b8f8fc8b1debdcd387f9bdcc67  buf.t/UPDATE
  050a08b8f8fc8b1debdcd387f9bdcc67  base.t/UPDATE

 rsync -nrCv buf.t/ base.t|wc -l
    281

Running with -n so nothing actually happens.  And 281 files are
processed 

  rsync -nrCv buf.t/ base.t|grep UPDATE
  UPDATE
  including UPDATE... Why?

Throwing in the -c (checksum checking) and it goes away.
Since I've already dropped timestamp owner group access etc it seems
rsync should leave this alone without the -c flag.