Projects that aren't meant to generate a wheel and `pyproject.toml`

Not precisely. It means that I think using the existing [project.dependencies] field locks us into the PEP 621 metadata in a way that might not be appropriate for all use cases of lockfiles (which I see as basically the same as the use cases for this proposal). I’m not suggesting we have another go at lockfiles, just that we look at this proposal in the context of what people want lockfiles for.

Specifically, making name and/or version optional. Conversely, if name and version are not optional, I don’t understand how the motivating VS Code feature will work - I certainly don’t want to be asked to specify a name and version every time I start a new project, and I’d be very unhappy if VS Code put some sort of “dummy” value in there - that would be just as bad as setuptools’ current behaviour of using UNKNOWN-0.0.0.

Definitely. But there are also other use cases. For example, I have a folder of “adhoc work”, that contains a number of independent scripts. These each have their own dependencies, and have no relationship to each other, apart from all being too small or temporary to warrant a “project directory”.

The point here is that while VS Code may want to ease beginners into a “directory per project” model, and may choose to only support that model, the Python packaging ecosystem doesn’t have the same freedom to declare existing workflows unsupported. So there’s a conflict of priorities, in that the VS Code motivating example has a limited set of use cases that matter, but the packaging standards can’t ignore the bigger picture.

Speaking very much as a user, I have things that I absolutely consider a “Python project” that are nothing more than a single script, or a single Jupyter notebook. These might well be stored in a directory that contains lots of other files and projects, none of which are in any way related to each other or to the Python project in question.

In terms of the title of this thread, a single script can very much be a “project that isn’t meant to generate a wheel”. And for such a script, there’s absolutely no way to associate a particular pyproject.toml with it. So I think that any solution to “how do we specify a project’s dependencies” must include some provision to explicitly name a project’s “dependency file”. That’s a benefit of the requirements.txt format that isn’t shared by pyproject.toml, for better or worse.

Agreed. And having such a thing would be good. But can we agree that any solution that mandates a specific named file would lose one important benefit of the requirements format, which is that the filename is up to the user? And if we don’t cover that, there will be people who need to continue using requirements files, because the new format doesn’t handle their needs.

One other issue I have, which is vaguely related to the “putting everything in pyproject.toml” comments, is that pyproject.toml is fundamentally a user-edited file. That’s not mandated by any spec, but PEP 518 listed “Reliable comments” and “Easy for humans to edit” as key factors in the choice of TOML as a format. If we allow project dependencies to be specified in pyproject.toml, we open up the possibility of tools expecting to write dependencies as a result of some sort of “add dependency” command, and IMO we need to be much more explicit that it’s not acceptable to lose comments or user formatting of pyproject.toml in the process. I have no idea if this is something that has been considered for the VS Code extension, so I don’t want to make it specifically about that particular use case, but given that format-preserving TOML editors aren’t common (neither tomli-w nor toml do this as far as I can see) it’s a non-trivial requirement.