[epistasis]

That works for your project, but then nobody can include you as a library without conflicts.

But having that lock file will allow somebody to reconstruct your particular moment in time in the future. Its just that those lock files do not exist for 99.9% of Python projects in time.

[dagw]

That works for your project, but then nobody can include you as a library without conflicts.

I think this is the core to much misunderstandings and arguments around this question. Some people are writing code that only they will run, on a python they've installed, on hardware they control. Others are writing code that has to work on lots of different versions of python, on lots of different hardware, and when being run in all kinds of strange scenarios. These two groups have quite different needs and don't always understand each other and the problems they face.

[zelphirkalt]

A lib can still lock its dependencies and have version ranges declared at the same time. The lock file is an artifact than is used to reproducibly build the lib, while the version ranges are used to see, whether some other project can use the lib.

It is only a matter of tooling. Locking ones dependencies remains the right thing to do, even for a lib.

[epistasis]

This is of course the right answer. But unfortunately it has only recently become supported by packaging tooling, and is extremely uncommon to encounter in the wild.

[LtWorf]

If you include a range you have to test with everything in the range.