venv activate.csh fails when user prompt contains newline

[brandyn]

Bug report

Bug description:

activate.csh uses "$prompt" in quotes like that, which fails when the user prompt contains a newline (error: unbalanced quotes).

Using $prompt:q or "$prompt:q" solves this with no harm, at least in tcsh (not sure about vanilla csh), at least for activate. (Deactivate may have similar issue.)

CPython versions tested on:

3.11

Operating systems tested on:

Linux

Linked PRs

• gh-122765: make prompt in activate.csh robust against unbalanced quotes and newlines #123751
• [3.13] gh-122765: make prompt in activate.csh robust against unbalanced quotes and newlines (GH-123751) #124185

[JacekDuszenko]

sent a PR with a fix however there is a similar issue with __VENV_PROMPT__ variable. When you set a custom prompt e.g. with --prompt='"' the script crashes @ https://github.com/python/cpython/blob/main/Lib/venv/scripts/posix/activate.csh#L22.

It's fixable by extracting the concatenated __VENV_PROMPT__ and prompt to a separate variable and then using it with ":q" on the next line while setting the prompt.
Can send another PR with a fix if sounds good.