base-typemaps.i and budgets

David Osguthorpe david.osguthorpe at
Thu Jan 16 18:52:49 EST 2014

In attempting to use qof query to look up budgets I have
come across an issue in base-typemaps.i for which Im not
sure would be the approved way to fix.

The first python Query class usage to attempt to return budgets returned a list of gnc_monetary
types, yet it should have been GncBudget.
(note the only implementation involved was in python setting up the query
and calling the query run function).

This appears to be a problem in the swig out typemap in base-typemaps.i for GList
type structures.
This typemap is defined differently for python versus scheme - here Im
specifically dealing with the Python version.

Currently there is a test for some specific list element data types
which then types each data element. However, there is a special
test for MonetaryList which maps the gnc_monetary type.

    else if ($1_descriptor == $descriptor(MonetaryList *))
        PyList_Append(list, SWIG_NewPointerObj(data, $descriptor(gnc_monetary *), 0));

The problem found returning budgets is that this matches any arbitrary GList whose
type is not defined in the previous else if components of the if structure,
hence a list of budgets is returned as a list of gnc_monetary type.

So far Ive created a separate out typemap for MonetaryList specifically which
assumes the elements of a MonetaryList are all gnc_monetary type.
(Its not clear to me its possible for it to be anything else).
I removed the above test from the more generic GList out typemap
and added a specific check for data elements of the swig budget type similar
the current style.

Question is why is this routine defined for various specific types
eg CommodityList *, SplitList *, AccountList *, LotList *, PriceList *, EntryList *
where it seems to me the elements must always be of a specific type.

Also, returning a void type for untested element types would seem to me to be better
than returning a wrong type for a generic GList (it may be possible to re-map the
swig void type in python later). 


More information about the gnucash-devel mailing list