[Distutils] [Python-Dev] How we can get rid of eggs for 2.6 and beyond

[Phillip J. Eby]

At 12:33 AM 3/25/2008 +0000, Floris Bruynooghe wrote:
>On Mon, Mar 24, 2008 at 04:57:44PM -0400, Alexander Michael wrote:
> > With that preamble, here's my attempt at an
> > explicit rationale for a database of installed packages (A.K.A. The
> > New PEP 262):
>
>Nice effort, thanks.
>
> > Rationale
> > =========
> > It is often necessary during the course of managing a python
> > installation for an administrator to determine the following things:
> >
> > 1. If the current installation state satisfies the requirements of a
> > new package being considered for installation.
> > 2. If it is safe for the administrator to upgrade or remove a package,
> > and if so, how (e.g. use a system-level package management tool).
> > 3. What files to remove in order to uninstall the package (if a
> > system-level package management tool was not used to install it).
> > 4. If the current installation was modified in-place or custom
> > configured in an way, so that such changes can be noted before
> > upgrading.
>
>I agree with 1 and 2, but 3 and 4 are optional I think.  They are not
>important for the different tools to interact AIUI.  As long as
>everyone only removes files they own all is fine.

Not quite - it's necessary to know which files are owned by a given 
package or tool in order to do this.  If you are installing a 
package, you need to know who owns any files that you're about to overwrite.


>Something that this requirement should probably explicitly describe:
>does this database only concern modules, i.e. installed in a directory
>that's on sys.path?

It will probably need to include scripts, data, etc.


>   My understanding is that it does.  However I'm
>unsure as to how that can be combined with supporting applications
>that require certain modules.  Would every tool need to keep track of
>the apps it installed separately to make sure that, when it's used to
>uninstall a module, it doesn't render an app that it installed
>useless?
>
>To tie in another part of this discussion, this could mean that module
>installation is forced to be a simple list of files while still
>allowing a Turing complete installer for applications.

These are currently open issues.