Using `tool.uv.dependency-groups` with a `uv.toml`

[mikeweltevrede]

Summary

When using the below pyproject.toml, running uv sync --all-groups fails (as expected) due to

Because the requested Python version (>=3.9, <4.0) does not satisfy Python>=3.11 and sphinx==8.2.3 depends on Python>=3.11, we can conclude that sphinx==8.2.3 cannot be used. And because test-dependency-groups:docs depends on sphinx==8.2.3 and your project requires test-dependency-groups:docs, we can conclude that your project's requirements are unsatisfiable.

# pyproject.toml
[project]
name = "test-dependency-groups"
version = "0.1.0"
description = "Add your description here"
readme = "README.md"
requires-python = "<4.0,>=3.9"
dependencies = [
    "requests==2.27.1; python_version == '3.9'",
    "requests==2.28.1; python_version == '3.10'",
    "requests==2.31.0; python_version == '3.11'",
    "requests==2.32.2; python_version == '3.12'",
    "requests; python_version > '3.12'",
]

[dependency-groups]
docs = [
    "sphinx==8.2.3",
]

I wanted to solve this by using tool.uv.dependency-groups as introduced in #13735. Indeed it works if I add it to the pyproject.toml like so, uv is indeed able to compile:

# pyproject.toml
[tool.uv.dependency-groups]
docs = {requires-python = ">=3.11"}

However, there are two cases that do not work as expected:

Error case 1: including tool.uv.dependency-groups in pyproject.toml while uv.toml exists

We have a uv.toml file for separation of concerns. When we include tool.uv.dependency-groups in pyproject.toml as the docs say and create an empty uv.toml file, and sync:

warning: Found both a uv.toml file and a [tool.uv] section in an adjacent pyproject.toml. The [tool.uv] section will be ignored in favor of the uv.toml file.

This still compiles successfully even though the tool.uv.dependency-groups section is not there. The warning message seems to indicate it would be ignored though, so I would expect this to fail like the first pyproject.toml without [tool.uv.dependency-groups].

Error case 2: including dependency-groups in uv.toml

We have a uv.toml file for separation of concerns. We include dependency-groups in uv.toml like so (and leave pyproject.toml as the base version):

# uv.toml
[dependency-groups]
docs = {requires-python = ">=3.11"}

I would expect this to succeed like the first pyproject.toml with [tool.uv.dependency-groups]. However, it fails with the same error message I mentioned first.

Conclusion

1. The warning raised when including tool.uv.dependency-groups in pyproject.toml while uv.toml exists does not actually seem to be correct.
2. The error raised when including dependency-groups in uv.toml is not expected.

Platform

Darwin 24.5.0 arm64

Version

uv 0.7.15 (4ed9c57 2025-06-25)

Python version

Python 3.12.10

[konstin]

Why are you creating the uv.toml next to the pyproject.toml, what's in that file?

[mikeweltevrede]

@konstin for separation of concerns, we like to use the uv.toml over the pyproject.toml just how we like to use ruff.toml and .coveragerc over [tool.ruff] and [tool.coverage] sections. Otherwise, it would blow up the pyproject.toml.

What we have in there, for example, is the [[index]] section to our corporate proxy.

[zanieb]

I don't think we support reading this from a uv.toml, it's project-specific metadata.

I am a bit confused about our merging behavior here, especially that we warn we'll ignore it but use the configuration?

[mikeweltevrede]

Thanks for updating the title @zanieb. Sorry, I forgot to make it a bit concrete.

Indeed then the support might not be there. I am fine with putting it in the pyproject.toml if that is currently the only supported way but then indeed the warning should not be emitted.

[Gankra]

• Case 1: Make warnings about masked [tool.uv] fields more precise #14325
• Case 2: Add missing validations for disallowed uv.toml fields #14322

[mikeweltevrede]

@Gankra Thanks for the quick action :) I am not a Rust programmer, so the code in #14322 is not apparent to me that it would indeed allow specifying something in pyproject.toml while a uv.toml exists. Is that the case? Or would this mean that if you want to use tool.uv.dependency-group that you cannot use a uv.toml?

[Gankra]

Yeah it's intentional that you have to use tool.uv.dependency-group here.

[mikeweltevrede]

Alright, great. So it is still allowed to use both a uv.toml and pyproject.toml with tool.uv.dependency-group?

[charliermarsh]

I think what you want is a uv.toml, and then a pyproject.toml with [dependency-groups] (instead of tool.uv.dependency-group, which is effectively deprecated in favor of the standards-complaint [dependency-groups]).