[Python-Dev] how important is setting co_filename for a module being imported to what file is set to? (original) (raw)

P.J. Eby pje at telecommunity.com
Mon Aug 31 21:08:51 CEST 2009


At 09:33 AM 8/31/2009 -0700, Guido van Rossum wrote:

Of course, tracking down all the code objects in the return value of marshal.load*() might be a bit tricky -- API-wise I still think that making it an argument to marshal.load*() might be simpler. Also it would preserve the purity of code objects.

Or maybe we could just do something like this:

 from new import code

 def with_changed_filename(code_ob, filename):
     def remap(ob):
         if not isinstance(ob, code):
             return ob
         return code(
             ob.co_argcount, ob.co_nlocals, ob.co_stacksize, 

ob.co_flags, ob.co_code, map(remap, ob.co_consts), ob.co_names, ob.co_varnames, filename, ob.co_name, ob.co_firstlineno, ob.co_lnotab, ob.co_freevars, ob.co_cellvars ) return remap(code_ob)

Granted, this takes a bit more memory than an in-place modification, but it's immediately usable and at least works wherever new.code is available.

(I've not tested the above, so it may not work. I seem to recall the last time I wrote something like this there was something tricky about handling co_freevars and co_cellvars; I think you may need to omit them if empty, or convert them to None, or from None to an empty tuple or some such rigamarole. And a 3.x version is left as an exercise for the reader. ;-) )



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