--append option description in manpage confusing

[Matt McCutchen]

On 8/2/07, Paul Slootman <paul at debian.org> wrote:
> I thought that --append simply meant that in cases where the destination
> file is shorter, data is simply appended without first checksumming the
> existing data, but that transfers would otherwise not be affected in any
> way, i.e. be performed in the usual manner as if --append was not
> specified. In other words, that --append was simply an optimization
> hint.

Oddly, rsync does checksum the existing data.  At first I thought this
was inconsistent with skipping source files that have longer
destination files, but I suppose it could be justified.  If --times is
on, rsync will set the destination mtime to match the source mtime
after a successful transfer, causing the quick check to pass on future
non-(--append) runs.  Thus, rsync wants to make sure the entire files
are identical so as not to deceive those future runs.  Wayne, was this
your thinking?

Matt