Module imports incorrect behaviour. BUG?

Question

Hi,
I was reading the forum and didn't find a solution on this problem, although I saw quite some problems with modules.
I have a problem with module imports in the library module. DB XML 2.5.16/ MacOS 10.6.2. Has been tested using DB XML shell and Java API
I have two modules: mod_slave.xq that is imported by mod_main.xq which in turn imported by the main query:
mod_slave.xq:
module "http://tntbase.mathweb.org/ns";
declare function test_slave() as xs:string {
  "test_slave"
mod_main.xq :
module namespace tnt = "http://tntbase.mathweb.org/ns";
import module namespace foo='http://tntbase.mathweb.org/ns' at 'file:/path/to/mods/mod_slave.xq';
declare function tnt:test_main() as xs:string {
  foo:test_slave()
main query:
import module namespace tnt = 'http://tntbase.mathweb.org/ns' at '/path/to/mods/mod_main.xq';
tnt:test_main()Executing the main query gives me an error:
query failed, Error: The graph of module imports contains a cycle for namespace 'http://tntbase.mathweb.org/ns' [err:XQST0073], <query>:1:1But there is no cycles: main query imports mod_main and mod_main imports mod_slave which imports nothing.
Moreover XQuery spec says: "it is a static error [err:XQST0073] if the graph of module imports contains a cycle (that is, if there exists a sequence of modules M1 ... Mn such that each Mi imports Mi+1 and Mn imports M1), *unless all the modules in the cycle share a common namespace*.". So even is there were a cycle, the error shouldn't be raised because my modules share a common namespace.
The next observation:
if I change the prefix foo to tnt in the mod_main, then I get the error:
query failed, Error: Namespace prefix has already been bound to a namespace [err:XQST0033], file:///path/to/mods/mod_main.xq:2:25But the spec says: "The namespace prefix specified in a module import must not be xml or xmlns [err:XQST0070], and must not be the same as any namespace prefix bound in the same module by another module import, a schema import, a namespace declaration, or *a module declaration with a different target namespace*". But I have the same namespace in the module declaration and a module import, so the error should not be raised.
The workaround for me for now is to put those two mods into different namespaces or unite both modules.
I would appreciate if anybody could confirm or point me to the real error in my modules. Thanks
Vyacheslav

Answer 1

Hi Vyacheslav,
I think you're analysis of both the XQuery spec and Berkeley DB XML is correct. The behaviour you're seeing is almost certainly a bug, but it's unlikely to be of a high enough priority to get attention in the near future. If fixing this is a priority to you, I expect it would be simple enough to point you in the right direction for the code that implements this.
John