REPL not respecting sys.ps1 sys.ps2 if set in HYSTARTUP

[atisharma]

The documentation for the REPL gives an example of setting the REPL prompt. Here is the simplest hyrc to illustrate the problem.

(import sys)
(setv sys.ps1 "* ")
(print f"sys.ps1 overridden to {sys.ps1}.")

Starting hy from bash (with HYSTARTUP set appropriately) does not replace sys.ps1. Setting sys.ps1 subsequently gives the expected behaviour.

> hy
sys.ps1 overridden to * .
Hy 0.28.0 using CPython(main) 3.11.7 on Linux
=> sys.ps1
"=> "
=>  (setv sys.ps1 "* ")
* 

[Kodiologist]

I think this used to work, but then I broke it as part of how I implemented restoration of the old sys.ps1 and sys.ps2 when quitting from a Hy REPL launched inside the Python REPL (#2355). Probably the right thing to do is have the user set different variables, say repl-ps1 and repl-ps2. The way the old setup worked, if you customized Hy's prompts, Python's would change to the same values, and vice versa.