bug#62528: 28.2; Emacsclient doesn't use COLORTERM

[Eli Zaretskii <eliz@gnu.org>]

> Date: Wed, 29 Mar 2023 17:06:18 +0200
> From: Vojtěch Balák <vojtech@balak.me>
> 
> When starting Emacs in a terminal emulator with 24 bit color support, 
> I would like it to take advantage of this. According to the FAQ 
> section 5.3, setting the variable COLORTERM to truecolor should 
> result in Emacs using 24 bit colors. But according to my observations, 
> this is not always true. 
> 
> Starting Emacs in these ways does result in it using true color: 
> TERM=xterm-256color COLORTERM=truecolor emacs -nw 
> TERM=xterm-direct COLORTERM= emacs -nw 
> TERM=xterm-direct COLORTERM= emacsclient -nw 
> 
> Starting it in these ways does result in it NOT using true color: 
> TERM=xterm-256color COLORTERM= emacs -nw 
> TERM=xterm-256color COLORTERM= emacsclient -nw 
> TERM=xterm-256color COLORTERM=truecolor emacsclient -nw 
> 
> The last one is the odd one out. According to my understanding, that
> should result in 24 bit color being used, but in practice it does not. 

I think you are misinterpreting what the documentation says.
COLORTERM=truecolor can only affect Emacs, it cannot affect the
display triggered by emacsclient.