bug#73865: cp 9.1+ fails to overwrite existing files even with -f under Cygwin

[Brian . Inglis]

On 2024-10-18 11:32, Paul Eggert wrote:
> On 2024-10-18 09:47, Brian Inglis wrote:
> > Hi folks,
> >
> > Versions of coreutils cp from 9.1-9.5 have been failing with error message:
> >
> >      "cp: cannot create regular file '/tmp/b/c': File exists"
> >
> > to overwrite existing files even with -f under Cygwin.
>
> What does strace say?

Thanks Paul,

That made me think to redo and reread the straces and I noticed that the 
basename was being accessed in the builddir, as patches were now accessing the 
basename not the realpath, so mea culpa!

That required a bunch of rebasing patches, and that now appears to work.

However, I now appear to have the issue that the Cygwin emulated "root" is not 
being detected and handled properly, so during tests, chgrp/chown/chmod 
--preserve-root is being ignored, also presumably rm!, tests are taking forever, 
and all my account and CI system mount points are being trashed by the tests, 
and build/gt-preserve-root.sh.XKPb/out is over 1GB!

I take it that should go into a different bug report, as I need to understand 
whether any access to "root" is just warned and skipped, or the command is 
terminated with prejudice.

The info docs section "Treating ‘/’ specially" appears to be ambiguous about the 
ch??? commands, whereas the man pages say "fail to operate recursively on ’/’".

Cygwin would probably want to default these commands to --preserve-root like rm, 
and also require -f --force to override, but ch??? redefine -f to --silent --quiet!

--
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer     but when there is no more to cut
                                -- Antoine de Saint-Exupéry