Support RDFLib 5.0.0

[Panaetius]

RDFLib released version 5.0.0 on 4th April, which many bugfixes detailed here https://github.com/RDFLib/rdflib/blob/master/docs/upgrade4to5.rst

Are there any plans to make cwltool work with RDFLib 5.0.0?

[mr-c]

Hello @Panaetius . I'm open to it ; do you want to send a PR to see if anything breaks?

[mr-c]

RDFLib v5 isn't in Debian yet, so I won't make it mandatory until then

https://packages.debian.org/sid/python-rdflib

[Panaetius]

I tried to look into it. schema-salad would have to be updated as well, so I looked at that first at https://github.com/Panaetius/schema_salad/tree/rdflib-5.0.0

There's an issue with rdflib.namespace.split_uri() now allowing : in names, so I added a small workaround.

The next issue is that rdflib.py3compat was removed in RDFLib/rdflib#519 which looks like a bigger change.

Without being familiar with rdflib, schema-salad or cwltool source code, this looks like it'd be a rather big effort to fix unfortunately

[mr-c]

Thank you @Panaetius for starting this, it will be needed at some point.

[mr-c]

We are Python3.5+ only now, so the removal of py3compat shouldn't matter, I don't think.

[Panaetius]

Actually, py3compat is not used in cwltool/schema_salad but the error was from rdflib-jsonld.

The requirements of rdflib-jsond say that it works with any rdflib > 4.2, but rdflib-jsonld 0.4.0 does not work with rdflib 5.0.0 due to the p3compat. See RDFLib/rdflib-jsonld#78
So if someone upgrades rdflib, pip would see the requirement for rdflib-jsonld as fullfilled, even though the versions are incompatible.

All the tests pass with 5.0.0 & rdflib-jsonld 0.5.0 for python 3.8 for both cwltool and schema_salad. They fail for python 3.5 but I think that's just some issue with tox caching versions on my end.

So everything seems to work with 5.0.0 and the minor fix, there's just the potential for a broken upgrade path where rdflib is upgraded but rdflib-jsonld is not.

On a side note, my bugfix for schema_salad just replicates the old functionality of split_uri() in case the new functionality didn't work. But it might be better to not rely on split_uri() at all and implement a specific function for what schema_salad wants to accomplish.