Re: [Info-mtools] [PATCH] permit empty disk in recursive mode

[Alain Knaff]

Hi,

On 9/8/21 2:34 PM, twoj stary wrote:
> Hello,
> 
> Attached is a patch to permit empty disk when the recursive directory
> listing option (via '-/' or '-s') is on.
> 
> The current state of affairs is while the non-recursive mode returns 0
> on exit for an empty disk, the recursive mode will return a non-zero
> status for such a disk:
> 
> $ dd if=/dev/zero of=./test.img count=360 bs=1024; mkfs.msdos ./test.img
> ...
> $ mdir -i ./test.img; echo $?
>  Volume in drive : has no label
>  Volume Serial Number is E723-8ABB
> Directory for ::/
> 
> No files
>                             362 496 bytes free
> 
> 0
> $ mdir -s -i ./test.img; echo $?
> mdir: File "." not found
> 1
> 
> Since an empty disk shouldn't necessarily trigger an error. I propose to
> add an environment variable to control it.

Thanks for the patch.

The behavior you observed is actually a Bug (IMHO), there is no reason
why empty (but existing) directories should trigger an error. And
actually, for non-recursive mode, they don't.

So, rather than making correct behavior conditional on an environment
variable, I applied the fix unconditionally.

This is now part of the new 4.0.36 release

[...]> Since some users may rely on the non-zero status in the recursive
mode
> (e.g. to detect empty disks), the existing behaviour is preserved:


IMHO, nobody should be relying on this peculiarity for checking whether
a disk is empty. Indeed, this is a potentially inefficient way to do so
if ever the disk is not empty with a well-supplied and deep directory
tree :-)

Regards,

Alain