bug#32148: 27.0.50; Shell is getting characters when enlarging window

[Eli Zaretskii]

> From: James Engel <jimengel1209@gmail.com>
> Date: Fri, 13 Jul 2018 13:50:07 -0400
> 
> I cloned from git the latest version of emacs.
> I start emacs without an init file to be sure nothing in there is causing the 
> issue.
> If I start a shell and split the window horizontally I get > > characters on 
> the command line in 
> the shell. It doesn’t matter if I shrink/enlarge vertically or horizontally I 
> get the same
> characters. The more times I do that the > > characters are added.
> Any idea why this is occurring and/or how to fix it?

How did you define your shell's interactive prompt?