[Python-Dev] Breaking undocumented API

[Toshio Kuratomi]

On Tue, Nov 09, 2010 at 01:49:01PM -0500, Tres Seaver wrote:
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> On 11/08/2010 06:26 PM, Bobby Impollonia wrote:
> 
> > This does hurt because anyone who was relying on "import *" to get a
> > name which is now omitted from __all__ is going to upgrade and find
> > their program failing with NameErrors. This is a backwards compatible
> > change and shouldn't happen without a deprecation warning first.
> 
> Outside an interactive prompt, anyone using "from foo import *" has set
> themselves and their users up to lose anyway.
> 
> That syntax is the single worst misfeature in all of Python.  It impairs
> readability and discoverability for *no* benefit beyond one-time typing
> convenience.  Module writers who compound the error by expecting to be
> imported this way, thereby bogarting the global namespace for their own
> purposes, should be fish-slapped. ;)
> 
I think there's a valid case for bogarting the namespace in this instance,
but let me know if there's a better way to do it::

# Method to use system libraries if available, otherwise use a bundled copy,
# aka: make both system packagers and developers happy::


Relevant directories and files for this module::

+ foo/
+- __init__.py
++ compat/
 +- __init__.py
 ++ bar/
  +- __init__.py
  +- _bar.py

foo/compat/bar/_bar.py is a bundled module.

foo/compat/bar/__init__.py has:

try:
    from bar import *
    from bar import __all__
except ImportError::
    from foo.compat.bar._bar import *
    from foo.compat.bar._bar import __all__

-Toshio
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