Why are most Python dependencies use depends_lib?

[Chih-Hsuan Yen]

Hi all,

In many Python libraries, depends_lib is used to store dependencies
listed in install_requires of setup.py. According to MacPorts
documents, depends_lib is for dependencies that are necessary for both
build-time and run-time, and depends_run is for those required in
run-time only. For most Python libraries, especially pure Python ones,
the build step is just copying Python sources files to a build/
directory, and dependencies are not checked. So, the question is: why
depends_lib is used in these cases instead of depends_run?

Regards,

Chih-Hsuan Yen