Hi Tim,
Here's a small demonstration of the bug:
--test.py-- def test(self, a_string, an_int, a_named_arg=1): """bug provoking?""" template = """a_string = %s; type(a_string) -> %s\n an_int = %s; type(an_int) -> %s\n a_named_arg = %s; type(a_named_arg) -> %s""" return template % (a_string, type(a_string), an_int, type(an_int), a_named_arg, type(a_named_arg)) ----
External methods need no "self" (and normally should have no "self") as first parameter, as they are not methods of some objects, I thought. But Zope seems to do some magic here.
--Script (Python)-- return container.test('tim', 10, a_named_arg=(1,1)) return container.test('tim', 10, (1,1)) ----
Indeed the first call should be illegal, as one passes only two non-keyword arguments, but the function has three arguments without default values. If I try to call the function from the python command line in an equivalent way as done here by the script, I get an TypeError: test() takes at least 3 non-keyword arguments (2 given). But Zope seems to mangle in the container/context into the "self" argument, if the following two conditions hold: 1. the first argument is named "self". (If the first argument is named "foo", it does not work.) 2. there are to less arguments to make a "normal" function call Condition 2. is true for the first call, but not for the second one. Here enough arguments are provided to make a plaing function call with the arguments: self='tim', a_string=10, an_int=(1,1), a_named_arg=(1,1), as defined by the caller or the default values. Thus I guess it is not a bug, but a feature. There is actually an example for this usage in the Zope Book (with the image thumbnails), but at least I failed to recognise the magic "self" mumble. Cheers, Clemens