Andreas Schwab <schwab@linux-m68k.org> writes:

> On Mai 06 2024, Thierry Volpiatto wrote:
>
>> The timestamp will be set to a few milliseconds in the past, yes, but is
>> this really a problem?
>
> You can touch a file that you don't own, if you have write permission.
> But you cannot set the time of such a file to an arbitrary value (even
> if that value happens to be the current time).

Thanks.  However this doesn't explain why dired-do-touch uses a
completing-read to complete 0 files, uses a default argument which is
not used with an empty prompt and doesn't fit with the info in prompt
even if the prompt is indeed right because finally the command exit with
current-time.
Also IIUC (I rarely use dired) when touching marked files the last file
will not have the same timestamp as the first.
Currently DEFAULT (if user press M-n) is only useful if one want to
modify timestamp of marked files to same timestamp as current.

All this seems incoherent and confusing.

I have now disabled dired-do-touch in Helm.

-- 
Thierry