[Python-Dev] PEP 3147: PYC Repository Directories

Nick Coghlan ncoghlan at gmail.com
Sun Feb 7 02:10:29 CET 2010

Ben Finney wrote:
> Right; I don't see who would disagree with that. I don't see any
> conflict between “decouple compiled bytecode file locations from source
> file locations” versus “predictable location for the compiled bytecode
> files”.

The more decoupled they are, the harder it is to manually find the
bytecode file.

With the current .pyc scheme, .pyr folders or an SVN style Python cache
directory, finding the bytecode file is pretty easy, since the cached
file is either in the same directory as the source file or in a

With any form of shadow hierarchy though, it gets trickier because you
have to:
1. Find the root of the shadow hierarchy
2. Navigate within the shadow hierarchy down to the point that matches
where your source file was

It's a fairly significant increase in mental overhead. It gets much
worse if the location of the shadow hierarchy root is configurable in
any way (e.g. based on sys.path contents or an environment variable).

Restricting the caching mechanism to the folder containing the source
file keeps things a lot simpler.


Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

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