Re-export binding versions to satisfied mypy --strict

[bact]

Modify the __init__.py generation so that bindings for each SPDX version will be re-exported.
To fix mypy compatibility when strict=true.

Currently this code:

from spdx_python_model import v3_0_1

will cause mypy (strict=true) error as:

Module "spdx_python_model" has no attribute "v3_0_1"

[bact]

The generated spdx_python_model/__init__.py will be:

# SPDX-License-Identifier: Apache-2.0
#
# Generated by generate-bindings at build time. DO NOT EDIT.
"""SPDX model in Python."""

from .bindings import v3_0_1
from .version import VERSION

__all__ = [
    "VERSION",
    "v3_0_1",
]

The generated spdx_python_model/bindings/__init__.py will be:

# SPDX-License-Identifier: Apache-2.0
#
# Generated by generate-bindings at build time. DO NOT EDIT.
"""SPDX model in Python — all supported SPDX versions."""

from . import v3_0_1

__all__ = [
    "v3_0_1",
]

The generated actual bindings will be handled normally by shacl2code.

[benjarobin]

I never noticed that, but is it a good ideal to load all binding versions from __init__?
Most of the time, an application only cares for a specific version. We are really slowing down the startup of applications by importing unnecessary versions.
Currently this is not an issue, since there is only one binding version.

[bact]

The current implementation loads *, which is effectively all versions.

We can also ask the developers to do

from spdx_python_model.bindings import v3_0_1

instead.

That would be cleaner.
(Need to update code examples in README in that case)

[benjarobin]

This is a breaking change. I am proposing to remove the import * (concerning the versions) from the __init__ .

And I prefer to change that as soon as possible. This way we are not living with this "issue" forever.

[bact]

This is a breaking change. I am proposing to remove the import * (concerning the versions) from the __init__ .

We have several __init__.py. Do you mean this one at the top-level?

spdx-python-model/src/spdx_python_model/__init__.py

Lines 5 to 6 in 4f82f94

	from .bindings import *
	from .version import VERSION

(Btw, this file is not part of current generation script, it will be used as-is.
The generation script in this PR will overwrite this file.)

[benjarobin]

The goal is when doing from spdx_python_model.bindings import v3_0_1 or something similar to import the binding of version 3.0.1, we do not want to load other versions, we only wants to load the verson 3.0.1.

If I am not mistaken, when doing from spdx_python_model.bindings import v3_0_1 some __init__ are executed.

[bact]

The goal is when doing from spdx_python_model.bindings import v3_0_1 or something similar to import the binding of version 3.0.1, we do not want to load other versions, we only wants to load the verson 3.0.1.

Agree and want to see that too.

The question here is how to deal with a statement like:

from spdx_python_model import v3_0_1

If we are to allow it (like it currently is), we need to import and re-export v3_0_1 in top-level __init__.py.

We can remove the import/re-export there, but that will be a breaking change for people who do import v3_0_1 that way.

(Anyway, since we are in 0.0.x version line, breaking changes should not be a surprise, if we need to)

[benjarobin]

As I said, this is a (major) breaking change.
This is no longer going to work: from spdx_python_model import v3_0_1.
Between v0.0.4 and version v0.0.5 there was also a major breaking change (compatibility was broken because shacl2code >= 1.0.0 was used, which changed various things).

[bact]

Thank you. I will open another PR to propose an alternative from this PR, based on our discussion. It will introduce a breaking change (while this PR will not).

The goal is to improve resource efficiency (when SPDX versions are growing) by moving away from import * in init.py, so we only load modules as needed instead of loading unused components. (Note that this is not currently an issue because there's only one version to load and by definition nothing is unused).

It should also keep typing annotation accurate (as intended similarly in this PR).