I accidentally removed Python-Ideas from the recipient list while posting this reply. On Wed, Feb 24, 2021, at 09:16, Random832 wrote:

On Wed, Feb 24, 2021, at 06:27, Christian Heimes wrote:

...

Separate directories don't prevent clashes and system breakage. But they provide an easy way to *recover* from a broken system.

I think it could be turned into a way to prevent them by A) having site-packages always take precedence over dist-packages [i believe this is already the case] in normal usage and B) providing an option to the interpreter, used by system scripts, to exclude site-packages entirely from the path.

Basically, site-packages would effectively be layered on top of "Lib + dist-packages" in a similar way to how a venv is layered on top of the main python installation - the inverse of the suggestion someone else in the thread made for the system python to be a venv. This wouldn't *exactly* be a venv because it wouldn't imply the other things that entering a venv does such as "python" [and script names such as pip] being an alias for the correct version of python, but it would provide the same kind of one-way isolation, whereby the "system environment" can influence the "normal environment" and not vice-versa, in the same way that packages installed in the main installation affect a venv [unless system-site-packages is disabled] but the venv obviously has no effect on the main installation.