Namespace prefix is serialized to "ns1" despite binding it.

[BalduinLandolt]

Hi, sorry to bother and to double-post (this here), but the more I think about it, the less I think it's intended behaviour:

In the following minimal test case:

from rdflib import Graph, Namespace, Literal, RDF

base = "http://test.com/ns"
foobar = Namespace("http://test.com/ns#")
g = Graph(base=base)
g.bind('foobar', foobar)

g.add((foobar.something, RDF.type, Literal('Blah')))
g.add((foobar.something, foobar.contains, Literal('a property')))

g.add((foobar.anotherthing, RDF.type, Literal('Blubb')))
g.add((foobar.anotherthing, foobar.contains, Literal('another property')))

print(g.serialize(format='turtle').decode("utf-8"))

I get

@base <http://test.com/ns> .
@prefix foobar: <http://test.com/ns#> .

<#anotherthing> a "Blubb" ;
    ns1:contains "another property" .

ns1:something a "Blah" ;
    ns1:contains "a property" .

what I'd expecte is more like

@base <http://test.com/ns> .
@prefix foobar: <http://test.com/ns#> .

<#anotherthing> a "Blubb" ;
    foobar:contains "another property" .

<#something> a "Blah" ;
    foobar:contains "a property" .

So either there is something I fundamentally don't understand about RDFLib and how to use namespaces, or there's something funky going on.
ns1, not being defined in the beginning, can't be resolved correctly, right?
Also, I'm not clear, why <#anotherthing> refers to @base while ns1:something (in opposition to <#something>) refers to the @prefix foobar.

If you could tell me what I'm doing wrong, I'd be very grateful! But also, this might be an indication that the documentation on that part is not 100% clear. :)

[BalduinLandolt]

I think I found the issue: @base and @prefix point to the same URI, which it doesn't seem to like.

If I remove the base, it turns out correct. If I don't bind the namespace, it adds it as ns1, so the result is correct (though ugly). Just if I have both, it doesn't work.

Is this behaviour intended? If so, it should be documented.

[nicholascar]

As per the answer to the same question in Stack Overflow: you need to complete the URI in the base declaration by adding the final #, or just don't use a base at all. As it is, the base is indeed clashing with the declared prefix.

There probably could be better handing of this in RDFlib but it's an extreme edge case predicated on incorrect declarations of a base that match a prefix, so I'm tempted to close the issue as I don't think anyone's likely to address it.

[BalduinLandolt]

Thank you for your reply, the final # indeed fixes it.
However, this brought another small "wonkiness" to light: now I get

@base <something#> .
@prefix foobar: <something#> .

<ting> a <thing-class> ;
    <contains> "Literal Property" .

So the @prefix is declared but never actually used (which makes sense, as it's the same as the @base).
But as it is never used, I figured I don't need to bind it in the first place.
But when I removed the binding, I got @prefix ns1: <something#> which again is never actually used.

In that sense, there is certainly some room for improvement... But I full well understand if that's not something that's getting addressed. It is an edge case after all.