buildlist task chokes on absolute path to parent Ivy module

[Mitch Gitman]

I'm using the parent Ivy module feature with the ivy.xml
/ivy-module/info/extends element. This works just fine whether I use a
relative path or an absolute path for the location attribute that locates
the parent ivy.xml. When I go to run ivy:buildlist, however, it only works
with the relative path. The moment it encounters an absolute path for the
parent location, it fails with:
… impossible to parse ivy file for …: ivyfile=…/ivy.xml
exception=java.text.ParseException: Problem occurred while parsing ivy
file: Unable to
 parse included ivy file for …#...;… in file:/…/ivy.xml

The exception is being thrown in XmlModuleDescriptorParser, line 422:
            if (parent == null) {
                throw new ParseException("Unable to parse included ivy file
for "
                        + parentOrganisation + "#" + parentModule + ";" +
parentRevision, 0);
            }

I'm seeing this with Ivy 2.2.0. I haven't tried yet to reproduce it with
Ivy 2.3.0-rc1.

Is anyone familiar with this behavior? Is this a known bug or is there
something I'm missing?

Depending on what I hear back, I can try creating an isolated, simple use
case using both 2.2.0 and 2.3.0-rc1.