bug#61658: 30.0.50; server-eval-at might handle unreadable results better

[Sean Whitton <spwhitton@spwhitton.name>]

Hello,

On Wed 22 Feb 2023 at 10:07PM +02, Eli Zaretskii wrote:

>> From: Sean Whitton <spwhitton@spwhitton.name>
>> Cc: 61658@debbugs.gnu.org
>> Date: Wed, 22 Feb 2023 10:28:05 -0700
>> [...]
>> Yes, that is a way to handle cases like this.  I was thinking it might
>> be better to have
>>
>>     (define-error 'server-return-invalid-read-syntax
>>                   "Remote function returned unreadable form"
>>                   'invalid-read-syntax)
>>
>> for a more flexible way to handle the situation.
>
> But what we have now already gives you almost the same information:
>
>   invalid-read-syntax, "#"
>
> I'm not sure I understand what would the above add to this.  Is
> "Remote function returned unreadable form" really that much more
> informative, when the user doesn't expect an error?

I'm thinking about the design of calling code, not errors that bubble up
all the way to the user.  If I want to catch this situation in calling
code, I can catch 'invalid-read-syntax'.  But for that to catch only the
errors I intend to catch, I have to assume that the only call to 'read'
in server-eval-at is the one that reads the remote daemon's output.  But
that's an implementation detail of server-eval-at, that could change.

-- 
Sean Whitton