[pypy-dev] bug with vars() in a nested function

holger krekel hpk at trillke.net
Tue Dec 23 17:53:20 CET 2003

[Alex Martelli Mon, Dec 22, 2003 at 10:23:24PM +0100]
> The implementation of vars() in builtin.py relies on a call to getdictscope() 
> to return the caller's locals as a dir, but unfortunately that doesn't work 
> when the caller of built-in vars() is a nested function -- nestedscope.py
> overrides fast2locals to ensure setting in self.w_locals the free variables
> in addition to the locals, and that w_locals is what getdictscope returns.

I think some further CPython analysis would be warranted here.
It's not very easy to see in which code paths and situations 
PyFrame_FastToLocals and PyFrame_LocalsToFast in CPython get invoked 
regarding nested scopes. In some theoretically critical use cases like exec 
and import-star statements the  compiler actually forbids it ...

So I committed a fix which modifies fast2locals to not put
bindings from outer scopes into the dict and added some tests (also
the builtin_functions_test now passes).  I have the feeling though
that there might be some more dark corners  ...



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