[Python-Dev] _not_found attribute on ImportError

Barry Warsaw barry at python.org
Mon Feb 11 15:23:34 CET 2013

On Feb 11, 2013, at 09:23 PM, Nick Coghlan wrote:

>On Mon, Feb 11, 2013 at 8:58 PM, Chris Withers <chris at simplistix.co.uk> wrote:
>> Have any other exceptions grown new attributes in Python 3?
>Off the top of my head, ImportError grew "name" and "path" attributes
>in 3.3, everything grew __cause__, __context__ and __traceback__
>attributes in 3.0 and the __suppress_context__ attribute in 3.3.
>PEP 3151 may have moved a few attributes around in 3.3 as well.
>If there are any others, you'll need to trawl the What's New documents
>looking for them.

Those public attributes should be documented.  _not_found should not be since
it's an implementation detail.  Also, Brett has left little TODO easter eggs
in the code which clearly indicate changes he plans for 3.4, although I don't
know where the plans for ModuleNotFound are documented.

In the meantime, I just ran a test against trunk, with the following change
and nothing broke afaict.

diff -r a79650aacb43 Lib/importlib/_bootstrap.py
--- a/Lib/importlib/_bootstrap.py	Mon Feb 11 13:33:00 2013 +0000
+++ b/Lib/importlib/_bootstrap.py	Mon Feb 11 09:16:51 2013 -0500
@@ -1640,6 +1640,7 @@
                     # TODO(brett): In Python 3.4, have import raise
                     #   ModuleNotFound and catch that.
                     if getattr(exc, '_not_found', False):
+                        del exc._not_found
                         if exc.name == from_name:

I won't commit this, but it really needs another hasattr() check to be
completely valid.


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