Add multiple C-API version infrastructure and C-API v1.1.0a.1

[jbreue16]

This PR adds infrastructure to implement support for multiple C-API versions and v1.1.0a1
The str lookup for the version number should be changed to the type @schmoelder suggested to make comparisons (>, < =) work
to be continued by @AntoniaBerger

• Add a test
• Developer guide

[AntoniaBerger]

@jbreue16 Is this the pull request you worked on Friday where you added the new C-API versioning to the cpp site? It’s cadet/CADET-Core#366.

[AntoniaBerger]

If I recall correctly, the idea is to call the _set_api function with a string instead of the dictionary of signatures. Then, within _set_api, compare which string is greater.
What’s the benefit of doing it this way?

[jbreue16]

yes exactly, but not using a string but this other type that Jo mentioned which supports comparisons of PEP440 version numbers. The benefit is that we can use this to successively add functions introduced in later (minor or pre-release) versions instead of repeating the whole list

[schmoelder]

from packaging.version import Version

latest = "5.1.0"

current = Version("5.2.0a_1")

if current > Version("5.1.0"):
    print("Something that was implemented in 5.2.0")

[jbreue16]

I dont see a difference here?

[jbreue16]

supported

[jbreue16]

v1.1.0a1 is smaller than v1.1.0

[jbreue16]

I think we can put a > 1.0.0 && < 2.0.0 here and then not set signatures = dict(CADET_API_V1_SIGNATURES.signatures_1_0_0) for the other cases

Also, we could add a last case with < 1.0.0 || > 1.1.0a1 that raises an exception? @schmoelder

[AntoniaBerger]

This would be my suggestions to implement the versioning and timeout in cadet_dll.py.

Key points:

• Create a dictionary _VERSION_SIGNATURES outside of classes that depends on the version.
• Add a new attribute _version to c-api classes. The _setup_api() method uses the corresponding _VERSION_SIGNATURES based on the _version.
• The dll_runner attempts to create the latest c-api version. If unavailable on the cpp site, it defaults to version 1.0.0.