bug#66020: (bug#64735 spin-off): regarding the default for read-process-output-max

[Dmitry Gutov]

Hi Paul and Eli,

On 24/09/2023 08:29, Eli Zaretskii wrote:

> > What do people think?
> I think we should increase the default size, and the rest (querying
> the system about the pipe size) looks like an unnecessary complication
> to me.
>
> I've added Paul Eggert to this discussion, as I'd like to hear his
> opinions about this stuff.

Do you think we can get this in before the emacs-30 branch is cut?

To summarize:

* Patch 1 (reduces consing when the default filter is used by moving it 
into C - skipping the creation of Lisp strings).
* Patch 2
  a) It ensures that the dynamic binding of read-process-output-max is 
saved when the process it created and used for its processing - ensuring 
that the current dynamic value is not just used when creating the pipe, 
but also later when reading from it.
  b) A few lines are outdated: part of the fix went in with bug#66288.
* Patch 3 can be replaced with just upping the default value of 
read-process-output-max to 65536.