[Toybox] more gnu nonsense: cp -n

[Ryan Prichard]

Apparently upstream coreutils "cp -n" changed between 9.1 and 9.2, and the
Debian maintainers reverted the change temporarily(?) and also added the
"non-portable" error.

In coreutils 9.1 and older, "cp -n" quietly skipped a file if the
destination existed, but as of 9.2, it instead prints an error and exits
with non-zero at the end. (I saw some stuff about "immediately failing" on
the Debian bug, but AFAICT, cp keeps going and fails at the end.) It does
look like the new 9.2+ behavior matches "cp -n" on macOS (14.3.1) (and
probably FreeBSD but I didn't test that).

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1058752

Someone complained to upstream, but it didn't go anywhere:

https://debbugs.gnu.org/cgi/bugreport.cgi?bug=62572

New behavior:

$ docker run -it fedora:39 bash -l
[root at 137183bb9d76 /]# cp --version | head -n1
cp (GNU coreutils) 9.3
[root at 137183bb9d76 /]# mkdir a b; touch a/x a/y
[root at 137183bb9d76 /]# cp -rnv a b; echo $?
'a' -> 'b/a'
'a/x' -> 'b/a/x'
'a/y' -> 'b/a/y'
0
[root at 137183bb9d76 /]# cp -rnv a b; echo $?
cp: not replacing 'b/a/x'
cp: not replacing 'b/a/y'
1
[root at 137183bb9d76 /]# rm -f b/a/x; cp -rnv a b; echo $?; ls b/a
'a/x' -> 'b/a/x'
cp: not replacing 'b/a/y'
1
x  y
[root at 137183bb9d76 /]# rm -f b/a/y; cp -rnv a b; echo $?; ls b/a
cp: not replacing 'b/a/x'
'a/y' -> 'b/a/y'
1
x  y

Old behavior:

$ docker run -it fedora:38 bash -l
[root at e296da330d05 /]# cp --version | head -n1
cp (GNU coreutils) 9.1
[root at e296da330d05 /]# mkdir a b; touch a/x a/y
[root at e296da330d05 /]# cp -rnv a b; echo $?
'a' -> 'b/a'
'a/x' -> 'b/a/x'
'a/y' -> 'b/a/y'
0
[root at e296da330d05 /]# cp -rnv a b; echo $?
0

-Ryan


On Mon, Apr 1, 2024 at 10:09 PM Rob Landley <rob at landley.net> wrote:

> On 4/1/24 10:31, enh via Toybox wrote:
> > hadn't seen this one before...
> >
> > cp: warning: behavior of -n is non-portable and may change in future;
> > use --update=none instead
> >
> > (consider me skeptical that a system without -n is going to have
> > --update=none...)
>
> Define non-portable? Freebsd 14 has -n, macos has -n, busybox cp has -n,
> and of
> course toybox (and thus android) has -n.
>
> Meanwhile:
>
> $ ./busybox cp --update=none one two
> cp: option '--update' doesn't allow an argument
> root at freebsd:~ # cp --update=none one two
> cp: illegal option -- -
> root at freebsd:~ # cp --update=none one two
> cp: illegal option -- -
> $ toybox cp --update=none one two
> cp: Unknown option 'update=none' (see "cp --help")
>
> Those clowns are explicitly advocating for a LESS portable option.
>
> This is why I'm not removing "egrep", which is a shell wrapper on my devuan
> system by the way:
>
> $ which egrep
> /bin/egrep
> $ cat /bin/egrep
> #!/bin/sh
> exec grep -E "$@"
>
> At least THAT one is easy for distributions to keep doing regardless of
> gnu/stupid.
>
> If the solution for cp -n isn't "distro patches out the stupid", then
> "install
> busybox cp" or just "use alpine". Spurious warnings from gnu are just that:
> spurious.
>
> Rob
> _______________________________________________
> Toybox mailing list
> Toybox at lists.landley.net
> http://lists.landley.net/listinfo.cgi/toybox-landley.net
>
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