Subject: bug#67510: 29.1; macOS accept-process-output line length limit of 1024

From: Eli Zaretskii <[email-masked]>
Date: Tue, 28 Nov 2023 16:51:11 +0200

> From: Max Arnold <[email-masked]>
> Date: Tue, 28 Nov 2023 11:14:09 +0700
> 
> blacken-buffer (from https://github.com/pythonic-emacs/blacken/blob/master/blacken.el) hangs
> at accept-process-output C call if a Python code line length exceeds 1024 characters.

Did you try binding process-connection-type to nil around the call to
blacken-buffer?