[Zope-dev] Strange behavior in modifying properties

[Rik Hoekstra]

Today I was experimenting a little with inserting and deleting from lines
properties (though I see no reason why this would not apply to other
properties. There was some strange behavior with modifying lists from dtml.
The method was as follows:


<dtml-var lst>

<dtml-call "lst.remove(REQUEST['remove_item'])">

<dtml-var lst>

where lst is a property of the containing folder. The proper way to do this
would be to make a local copy of the list and replacing the property with
it, but that's not the point.

Now, as far as I'm aware this method should have no effect on the properties
of the folder, or is it. But is has: it changes the property and it seems to
have a permanent effect.
But, as it is not a completed transaction changes are undone if ZServer is
closed down.

A few questions:
- has anyone seen this as well
- could someone explain me how this works
- is this a bug or a feature
- if it is a feature - could someone show me its use

Rik Hoekstra