bug#65902: 29.0.92; emacsclient-mail.desktop fails due to complicated escaping

[sbaugh]

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

> On Okt 22 2023, sbaugh@catern.com wrote:
>
>> +Exec=emacsclient --alternate-editor= --eval '(message-mailto (pop 
>> server-eval-args-left))' %u
>
> This line is not valid according to the specs.

Is that because of the single quotes surrounding spaces?  Are quoted
strings not permitted?

Would the following be valid:

Exec=emacsclient --alternate-editor= --eval '(message-mailto)' %u

or perhaps

Exec=emacsclient --alternate-editor= --eval (message-mailto) %u

That's easily achievable.