[Python-Dev] Importing .pyc in -O mode and vice versa (original) (raw)

Greg Ewing greg.ewing at canterbury.ac.nz
Thu Nov 9 00:29:43 CET 2006

Martin v. Löwis wrote:

a) the directory cache is out of date, and you should re-read the directory b) the module still isn't there, but is available in a later directory on sys.path (which hasn't yet been visited) c) the module isn't there at all, and the import will eventually fail.

How can the interpreter determine which of these it is?

It doesn't need to - if there is no file for the module in the cache, it assumes that the cache could be out of date and rebuilds it. If that turns up a file, then fine, else the module doesn't exist.

BTW, I'm not thinking of cacheing individual directories, but scanning all the directories and building a single qualified_module_name -> pathname mapping. If the cache gets invalidated, all the directories along the path are re-scanned, so a new module will be picked up wherever it is on the path.

-- Greg

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