[ python-Bugs-1542308 ] Nested finally in generators don't follow PEP 342

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Bugs item #1542308, was opened at 2006-08-17 18:56
Message generated for change (Comment added) made by gvanrossum
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Category: Python Interpreter Core
Group: Python 2.5
Status: Open
Resolution: None
Priority: 8
Submitted By: Bob Ippolito (etrepum)
Assigned to: Nobody/Anonymous (nobody)
Summary: Nested finally in generators don't follow PEP 342

Initial Comment:
The close() and GC interaction of generators that use yield inside of finally 
blocks doesn't execute correctly when nested. See the attached example.

More information about the issue is in the Mozilla bug tracker (they found 
a similar bug in their implementation for JS 1.7):
https://bugzilla.mozilla.org/show_bug.cgi?id=349012

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>Comment By: Guido van Rossum (gvanrossum)
Date: 2006-08-22 16:47

Message:
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I lost my patience halfway through reading the Mozilla bug
tracker, but IMO this works as designed.  The philosophical
question is, would you rather see the outer finally clause
reached in your example, or would you rather see the
following generator terminated upon close? (If you "fix" the
former, the latter ends up in an infinite loop when you
attempt to close() or GC it.)

def gen():
  while True:
    try:
      yield
    except:
      pass

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