bug#36831: Enhance directory move. (was Re: bug#36831: enhance 'directory not empty' message)

[L A Walsh]

On 2019/08/02 19:47, Assaf Gordon wrote:
> Can new merging features be added to 'mv'? yes.
> But it seems to me these would be better suited for 'higher level'
> programs (e.g. a GUI file manager).
---
        But neither the person who posted the original bug on this
nor I are using a GUI, we are running 'mv' GUI, we use the cmd line on linux, 
so that wouldn't
be of any use.

If the command was named 'ren', then I'd expect it to be dummer,
but 'mv'/move seem like it should be able to move files from
one dir into another.

But you say posix wants it to perform as a rename?
I know, create a 're' command (or 'rn') for rename, and have
it do what 'mv' would do.  Maybe posix would realize it would
be better to have re/rn behave like rename, and 'mv' to
behave it was moving something.

So if I have:
mkdir A B
touch A/foo B/fee

So when I look at the system call on linux for rename:
       oldpath can specify a directory.  In this case, newpath must either not
       exist, or it must specify an empty directory.
        (complying with POSIX_C_SOURCE >= 200809L)

So move should give an error: Nope:

mv A B
> tree B
B
├── A
│   └── foo
└── fee

1 directory, 2 files

So mv is violating POSIX - it didn't do the rename, but moved
A under B and neither dir had to be empty.

Saying it has to follow POSIX when it doesn't appear to, seems
a bit contradictory?