Conflicting dependencies for a test matrix

[delfick]

Hi,

I want to make it so that I can run the tests for my project against django==4.2 and separately against django==5.1, which means if I want that represented in the uv.lock I need to create conflicting dependencies.

But I can't figure out how to make this work and I end up with both versions of django in the virtualenv, which means it's always running the tests with django 5.1

old-django = [
    "django-stubs==5.1.1",
    "django==4.2.16"
]
new-django = [
    "django-stubs==5.1.1",
    "django==5.1.3"
]

[tool.uv]
conflicts = [
    [
      { group = "old-django" },
      { group = "new-django" },
    ],
]

Seems to be enough to make uv lock work, but then I do uv run --group old-django pytest and it is still using django 5.1

My branch where I'm trying to work this out is over at delfick/extended-mypy-django-plugin#65

The way I'm doing it currently is uv run --with django==4.2.16 pytest and uv run --with django==5.1.3 pytest but this means it doesn't end up in the uv.lock.

[samypr100]

Related #6830

[zanieb]

I tried to reproduce this, but could not:

❯ uv init example
❯ cd example
❯ uv add --group old django==4.2.16
Using CPython 3.12.7
Creating virtual environment at: .venv
Resolved 5 packages in 337ms
Prepared 3 packages in 651ms
Installed 3 packages in 76ms
 + asgiref==3.8.1
 + django==4.2.16
 + sqlparse==0.5.2
❯ uv add --group new django==5.1.3
  × No solution found when resolving dependencies:
  ╰─▶ Because example:new depends on django==5.1.3 and example:old depends on django==4.2.16, we can conclude that example:new and example:old are incompatible.
      And because your project depends on example:new and example:old, we can conclude that your project's requirements are unsatisfiable.
  help: If you want to add the package regardless of the failed resolution, provide the `--frozen` flag to skip locking and syncing.

❯ vi pyproject.toml
❯ cat pyproject.toml
[project]
name = "example"
version = "0.1.0"
description = "Add your description here"
readme = "README.md"
requires-python = ">=3.12"
dependencies = []

[dependency-groups]
old = [
    "django==4.2.16",
]
new = [
    "django==5.1.3",
]
dev = [
    "pytest>=8.3.4",
]

[tool.uv]
conflicts = [
    [
      { group = "old" },
      { group = "new" },
    ],
]

❯ uv add --group new django==5.1.3
Resolved 6 packages in 159ms
Prepared 1 package in 717ms
Uninstalled 1 package in 280ms
Installed 1 package in 58ms
 - django==4.2.16
 + django==5.1.3

❯ touch conftest.py
❯ vi conftest.py

❯ cat conftest.py
import importlib

import pytest


def pytest_report_header(config: pytest.Config) -> list[str] | None:
    return [f"Django: {importlib.metadata.version('django')}"]

❯ uv add --dev pytest
Resolved 11 packages in 267ms
Prepared 4 packages in 109ms
Installed 4 packages in 8ms
 + iniconfig==2.0.0
 + packaging==24.2
 + pluggy==1.5.0
 + pytest==8.3.4

❯ uv run pytest
==================================================================================================================== test session starts =====================================================================================================================
platform darwin -- Python 3.12.7, pytest-8.3.4, pluggy-1.5.0
Django: 5.1.3
rootdir: /Users/mz/workspace/example
configfile: pyproject.toml
collected 0 items                                                                                                                                                                                                                                            

=================================================================================================================== no tests ran in 0.00s ====================================================================================================================
❯ uv run --group old pytest
Uninstalled 1 package in 267ms
Installed 1 package in 59ms
==================================================================================================================== test session starts =====================================================================================================================
platform darwin -- Python 3.12.7, pytest-8.3.4, pluggy-1.5.0
Django: 4.2.16
rootdir: /Users/mz/workspace/example
configfile: pyproject.toml
collected 0 items                                                                                                                                                                                                                                            

=================================================================================================================== no tests ran in 0.00s ====================================================================================================================

[zanieb]

Ah actually I'm successful if I add the stubs package

❯ uv add django-stubs==5.1.1
Resolved 15 packages in 277ms
Prepared 4 packages in 155ms
Installed 5 packages in 694ms
 + django==5.1.3
 + django-stubs==5.1.1
 + django-stubs-ext==5.1.1
 + types-pyyaml==6.0.12.20240917
 + typing-extensions==4.12.2
❯ uv run --group old pytest
Uninstalled 2 packages in 264ms
Installed 2 packages in 741ms
==================================================================================================================== test session starts =====================================================================================================================
platform darwin -- Python 3.12.7, pytest-8.3.4, pluggy-1.5.0
Django: 5.1.3
rootdir: /Users/mz/workspace/example
configfile: pyproject.toml
collected 0 items                                                                                                                                                                                                                                            

=================================================================================================================== no tests ran in 0.00s ====================================================================================================================

[zanieb]

I believe this is a bug with the same root cause as #9289

We're writing ambiguous entries to the lockfile.

Will be resolved by a solution like #9370

[delfick]

awesome, thanks :)

[BurntSushi]

Yup, I can confirm that this will be fixed by #9370.

[delfick]

🥳