Backwards incompatibility introduced in [5091]: obj.has_key(x) -> x in obj

[Jeremy Dunck]

In [5091], Django was changed to favor "key in container" rather than "container.has_key(key)".

This inadvertantly introduced a backwards incompatibility.

"
...[I]f you have PyXML installed for all the extra
goodies that supplies, that is transparently into the xml.* namespace
(via _xmlplus) ... in that case, AttributesImpl is missing a feature."

and

"
...[P]ushing an instance of xml.sax.xmlreader.AttributesImpl onto
my Context..., no matter what the value... is, what's passed to
xml.sax.xmlreader.AttributesImpl is int(0).

This was causing a KeyError in template attribute lookup.
"

On July 17, Malcolm said he'd back out the affecting changes, but it hasn't been done.

This should either be backed out or noted as an incompatibility. And it'd be nice if PyXML were fixed. :)

(See thread for more detail:
​http://groups.google.com/group/django-developers/browse_thread/thread/2ae80a504fa31d81/87b693ce3e52fcf2
)