Both in Zope2 and in Django you need to work with attributes called id. This is a shame since it's such a huge pitfall. Despite having done Python programming for so many years I today fell into this pitfall twice!! The pitfall is that id is a builtin function, not a suitable variable name. The reason is that I was changing a complex app to use something called the UUID as the indentifier instead of the ID which happened to be a name of a primary key in a table.

This meant lots of changes and I tested and tested and kept getting really strange errors. I took the whole thing apart and put it back together when I discovered my error of checking if variable id was set or not. id, if undefined, defaults to the builtin function id() which will always return true on bool(id).

It's been a long day. I'm going home. Two newbie mistakes in one programming session. I'm sure I'm not the only one who's been trapped by this.

Roberto - 17 September 2008 [«« Reply to this]
I've done that a lot too, now I just use id_ as the variable name.
Peter Bengtsson - 18 September 2008 [«« Reply to this]
I've changed most places to 'oid' as in "object ID".
nih - 18 September 2008 [«« Reply to this]
this is also common in wxPython, i only realised this was an issue after running one of my programs through pylint, which flags up something like 'using builtin function id', so i'm now also using id_


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