bug#51177: 29.0.50; stop-process on pipes

[Helmut Eller <eller.helmut@gmail.com>]

On Sat, Oct 16 2021, Eli Zaretskii wrote:
>> Running 1 tests (2021-10-16 18:21:53+0200, selector ‘t’)
>> Test test-filter=t backtrace:
>>   t(#<process foo> "0+0 records in\n0+0 records out\n")
>>   accept-process-output(#<process foo>)
>
> What do we expect to happen when a Lisp program calls
> accept-process-output on a process that is stopped?

I would not expect that the symbol t will be called.

I would expect that accept-process-output on a process initialized with

   (make-process ... :filter t)

and

   (set-process-filter (make-process ...) t)

does the same.

I would expect that accept-process-output checks and maybe updates the
process-status.  If the process-status hasn't changed, then the return
value of accept-process-output should be nil.

Helmut