Dear Eli,

Thank you very much for your helpful and rapid response.  Emacs has
never let me down in daily use from 1993 till this problem came up.

On 12/04/23 18:39 +0300, Eli Zaretskii wrote:
>> Date: Wed, 12 Apr 2023 17:05:13 +1000
>> From: Nick Urbanik <nicku@nicku.org>
>>
>>
>>
>> 1. Start emacs with emacs -Q
>> 2. Read in a large python file (3100 lines long, more than 10,000
>>     characters)
>
>Thanks.
>
>Please post such a file, or a URL where it could be downloaded.  I
>couldn't easily find such a large file on my system.

It turns out that it is not the size, but some pathological
arrangement of the code.  I have provided a much smaller sample here
that I can reproduce the problem with by:

1. Move the cursor to below the from elesewhere import ... line.
2. Press Enter
3. Type:
def function():
     """

4. At this point, CPU usage goes to 100%, I cannot type anything else
into the buffer, but I can send a USR2 signal to end the 100% CPU
usage, but the buffer has only partial syntax colouring.
>
>> 3. Near the top, type the following:
>>
>> def function():
>>     """
>>
>> 4. No further input is accepted.
>> 5. CPU usage is 100% as shown in /usr/bin/top
>> 6. type kill -USR2 {process_id_of_emacs-Q}
>>     and the emacs window closes.
>> 7. From my emacs started without '-Q', when I type
>>     killall -USR2 emacs
>>     I see:
>> Debugger entered--entering a function:
>
>I suspect this is already fixed in Emacs 29, but I cannot verify
>without a file that reproduces the problem in Emacs 28.

I will build an RPM package of emacs 29 and test that.
-- 
Nick Urbanik             http://nicku.org           nicku@nicku.org
GPG: 7FFA CDC7 5A77 0558 DC7A 790A 16DF EC5B BB9D 2C24 ID: BB9D2C24