[Cheetahtemplate-discuss] [PATCH] Prevent NameMapper from gobbling up exceptions

[R. T. B. <ty...@sl...>]

Howdy all, I figured I'd notify the list, I discovered another bug when
hunting down one of our own issues.

There was/is an error in the NameMapper code that causes objects that
override __getattr__() (and potentially raise exceptions) to get
swallowed up inside of NameMapper.py:_valueForName()

Basically the use of hasattr(obj, key) causes getattr() to break
prematurely and return False, swallowing an exception in the process.

Attached is a patch that fixes this in the C version of the NameMapper
module as well as the Python version. I've included a regression test
written against the stock PyUnit to both exhibit the behavior and
correct it.

(If you're curious as to how anybody might have this error, we're using
__getattr__() in some instances to provide transparent distributed cache
access on objects passed in on the searchList, and there are rare
occassions when cache.read() might raise, and Cheetah swallows the cache
read exception)

As my previous patches, I've pushed this one up into my GitHub
repository of Cheetah (https://github.com/rtyler/cheetah/tree), these
changes in particualr have been committed to the "next" branch if you're
interested.
-- 
Cheers,
-R. Tyler Ballance
Slide, Inc.