python24.zip

[Robin Becker]

Dieter Maurer wrote:
.....
> 
> The question was:
> 
>    "should python start up with **non-existent** objects on the path".
> 
> I think there is no reason why path needs to contain an object
> which does not exist (at the time the interpreter starts).
> 
> In your use case, "python24.zip" does exist and therefore may
> be on the path. When "python24.zip" does not exist, it does
> not contain anything and especially not "site.py".
> 

I think this was my intention, but also I think I have some concern over
having two possible locations for the standard library. It seems non pythonic
and liable to cause confusion if some package should manage to install
python24.zip while I believe that python24\lib is being used.

> 
> I recently analysed excessive import times and
> saw thousands of costly and unneccesary filesystem operations due to:
> 
>   *  long "sys.path", especially containing non-existing objects
> 
>      Although non-existent, about 5 filesystem operations are
>      tried on them for any module not yet located.
> 
>   *  a severe weakness in Python's import hook treatment
> 
>      When there is an importer "i" for a path "p" and
>      this importer cannot find module "m", then "p" is
>      treated as a directory and 5 file system operations
>      are tried to locate "p/m". Of course, all of them fail
>      when "p" happens to be a zip archive.
> 
> 
> Dieter

I suppose that's a reason for eliminating duplicates and non-existent entries.

-- 
Robin Becker