Re: wait_reading_process_ouput hangs in certain cases (w/ patches)

[Paul Eggert]

On 11/15/2017 06:03 AM, Matthias Dahl wrote:
> The crucial part is: ALL data has been read from our wait_proc while we
> were running timers or filters -- and no further data will become
> available until there is some interaction again with the process.

Sure, but how do we know that the data read while running timers and 
filters was being read on behalf of our caller? Perhaps a timer or 
filter fired off some Elisp function that decided to read data for its 
own purposes, unrelated to our caller. We wouldn't want to count the 
data read by that function as being data of interest to our caller.

In your ispell case we know that the timers and filters are reading on 
ispell's behalf, so the proposed fix should be OK. (If memory serves, 
integer overflow isn't possible for ispell either.) But I don't yet see 
how the fix works in general.