[Python-3000] PEP 3134 status ? (Exception Chaining)

[Antoine Pitrou]

Hello,

Along the discussion of issue 3021 (a patch for the exception nesting issues
already discussed here), Adam Olsen suggested I bring on this mailing-list
the subject of PEP 3134. Indeed, he remarked, the patch I proposed, by 
implementing proper exception stacking, should make it relatively easy to 
adding the '__context__' attribute of exceptions a.k.a. implicit exception 
chaining.

However, the official status of PEP 3134 is not clear (it is not officially 
accepted, though many features of it have been implemented). Should my patch 
in issue 3021 try to be as much "PEP 3134-compliant" as possible?

More precisely, the fact that PEP 3134 proposes implicit exception chaining 
to also work inside finally blocks implies a more complicated implementation 
(mostly because the 'with' statement (ab)uses the existing try/finally 
infrastructure and likes to muck around with the interpreter stack).

In any case, both versions of the patch are available: the one which also
implies exception stacking in "finally" blocks, and the one which doesn't. 

Regards

Antoine.