Dependencies

Types of dependencies

skpro has three types of dependencies:

• “core” dependencies that are required for skpro to install and run

• “soft” dependencies that are required to import or use specific, non-core functionality

• “developer” dependencies are required for developing skpro but not required of end-users (e.g., pre-commit)

• “test” dependencies are required for running skpro’s unit tests

Making it easy to install and use skpro in a variety of projects is on of skpro’s goals. Therefore, we seeks to minimizing the number of dependencies needed to provide the proejct’s functionality.

Soft Dependencies

A soft dependency is a dependency that is only required to import certain modules, but not necessary to use most of the package’s functionality. Accordingly, soft dependencies are not automatically installed alongside skpro. If you want to install soft dependencies, you’ll either need to do so manually or use follow the installation instructions and install the optional “[all_extras]” version of the package.

Adding a soft dependency

The project tries to keep its dependencies, including soft dependencies, minimized. Core developers will consider the pros and cons of any additional soft dependency when reviewing Pull Requests. In the event you need to add a new soft dependency or changing the version of an existing one, the following files need to be updated:

• pyproject.toml, adding the dependency or version bounds in the all_extras dependency set. Following the PEP 621 convention, all dependencies including build time dependencies and optional dependencies are specified in this file.

Informative warnings or error messages for missing soft dependencies should be raised, in a situation where a user would need them. This is handled through our _check_soft_dependencies utility.

There are specific conventions to add such warnings in BaseObject-s. To add BaseObject with a soft dependency, ensure the following:

• imports of the soft dependency only happen inside the object (e.g., a particular methods or in __init__ after calls to super(cls).__init__).

• the python_dependencies tag of the BaseObject is populated with a str, or a list of str, of import dependencies. Exceptions will automatically raised when constructing the BaseObject in an environment without the required packages.

• in the python module containing the BaseObject, the _check_soft_dependencies utility is called at the top of the module, with severity="warning". This will raise an informative warning message at module import.

• In a case where the package import differs from the package name (i.e., import package_string is different from pip install different-package-string), the _check_soft_dependencies utility should be used in __init__. Both the warning and constructor call should use the package_import_alias argument for this.

• If the soft dependencies require specific python versions, the python_version tag should also be populated, with a PEP 440 compliant version specification str such as "<3.10" or ">3.6,~=3.8".

Core or developer dependences

Core and developer dependencies can only be added by core developers after discussion in a core developer meeting or in the project’s communication channels.

When adding a new core dependency or changing the version of an existing one, the following files need to be updated:

• pyproject.toml, adding the dependency or version bounds in the dependencies dependency set.

When adding a new developer dependency or changing the version of an existing one, the following files need to be updated:

• pyproject.toml, adding the dependency or version bounds in the dev dependency set.