fix #4615: chown isnt showing a message

[djedi23]

This PR add a message when the current user is not matched by the from argument and the verbosity is increased.
Two different messages are displayed depending if a group is set or not to match the observed behavior on GNU chown.

This PR fixes #4615.

[sylvestre]

Seems that the GNU test isn't fixed:

FAIL: tests/chown/basic
=======================

chown: ownership of 'f' retained as root
--- exp	2023-04-21 06:05:45.448369817 +0000
+++ out	2023-04-21 06:05:45.444369729 +0000
@@ -1 +0,0 @@
-ownership of 'f' retained as root
make[5]: *** [Makefile:21405: tests/test-suite-root.log] Error 1
chown: cannot dereference 'nf': No such file or directory
--- exp	2023-04-21 06:05:45.452369904 +0000
+++ out	2023-04-21 06:05:45.448369817 +0000
@@ -1 +0,0 @@
-failed to change ownership of 'nf' to 0
FAIL tests/chown/basic.sh (exit status: 1)

[github-actions]

GNU testsuite comparison:

Congrats! The gnu test tests/tail-2/inotify-dir-recreate is no longer failing!

[djedi23]

Printing the message in stdout fixes the first part of the GNU test.
The test still fails on the diagnostics for non existent files...

[github-actions]

GNU testsuite comparison:

Congrats! The gnu test tests/tail-2/inotify-dir-recreate is no longer failing!

[sylvestre]

Maybe move this into a function?

fn print_verbose(&self, path: &Path, uid: u32, gid: Option<u32>) {
    if self.verbosity.level == VerbosityLevel::Verbose {
        match gid {
            Some(gid) => {
                println!(
                    "ownership of {} retained as {}:{}",
                    path.quote(),
                    entries::uid2usr(uid).unwrap_or_else(|_| uid.to_string()),
                    entries::gid2grp(gid).unwrap_or_else(|_| gid.to_string()),
                );
            }
            None => {
                println!(
                    "ownership of {} retained as {}",
                    path.quote(),
                    entries::uid2usr(uid).unwrap_or_else(|_| uid.to_string()),
                );
            }
        }
    }
}

and call:
print_verbose(path, uid, self.dest_gid.map(|_| meta.gid()));

[github-actions]

GNU testsuite comparison:

Congrats! The gnu test tests/tail-2/inotify-dir-recreate is no longer failing!

[cakebaker]

With GNU chown 9.3, the following commands:

$ chown -v --from=42 :43 f
$ chown -v --from=:42 :43 f
$ chown -v --from=42:42 :43 f

all output:

group of 'f' retained as dho

uutils chown, on the other hand, returns in all three cases:

ownership of 'f' retained as dho:dho

[djedi23]

Corrected.

[cakebaker]

Thanks!