[Python-Dev] Python install layout and the PATH on win32 (original) (raw)

R. David Murray rdmurray at bitdance.com
Tue Mar 20 23:45:43 CET 2012

On Wed, 21 Mar 2012 09:09:38 +1100, Mark Hammond <skippy.hammond at gmail.com> wrote:

On 21/03/2012 5:50 AM, Merlijn van Deen wrote: > I asked a question about this on IRC, to which the response was that > there were two main reasons to install python in c:\pythonxy: > > 1 - issues due to spaces ('Program Files') or non-ascii characters in > the path ('Fișiere Program' on a Romanian windows). These issues are > supposed to be fixed by now (?). > 2 - issues due to permissions - installing python / packages in > %programfiles% may require administrator rights.

Apart from personal preference (ie, I prefer the status quo here), the second issue is a bit of a killer. Even an administrator can not write to Program Files unless they are using an "elevated" process (ie, explicitly use "Run as Administrator" and confirm the prompt. This means that any installer wanting to write .py files into the Python install must be elevated, and any Python process wanting to generate .pyc files must also be elevated. So even if an installer does arrange elevation, unless that installer also compiles all .pyc and .pyo files at install time, Python would fail to generate the .pyc files on first use. While Python will probably fail silently and still continue to work, it will have a significant performance impact.

So windows requires admin privileges to install to Program Files, but not to install to '/'? How novel. (You can perhaps tell that I'm not a windoows user). My understanding, though, is that Python does make a distinction between a system install of Python and a per-user one, so I don't think your objection really applies.

That said, there is an open bug in the tracker about the insecurity of a system install of python (exactly that the files are writable by anyone). So that would have to be solved first. I'd say this is definitely a separate issue from Van's discussion, and the only reason one might want to tie them together at all is "well, we're changing the directory layout anyway".

--David

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