Repeated markers in resolution-markers

[charliermarsh]

If you lock:

[project]
name = "project"
version = "0.1.0"
requires-python = ">=3.12.0"
dependencies = []

[project.optional-dependencies]
cpu = [
  "torch>=2.5.1",
  "torchvision>=0.20.1",
]
cu124 = [
  "torch>=2.5.1",
  "torchvision>=0.20.1",
]

[tool.uv]
conflicts = [
  [
    { extra = "cpu" },
    { extra = "cu124" },
  ],
]
environments = ["platform_system != 'Darwin'", "platform_system == 'Darwin'"]

[tool.uv.sources]
torch = [
  { index = "pytorch-cpu", extra = "cpu", marker = "platform_system != 'Darwin'" },
]
torchvision = [
  { index = "pytorch-cpu", extra = "cpu", marker = "platform_system != 'Darwin'" },
]

[[tool.uv.index]]
name = "pytorch-cpu"
url = "https://download.pytorch.org/whl/cpu"
explicit = true

Then the top of the lockfile includes:

resolution-markers = [
    "platform_system != 'Darwin'",
    "platform_system != 'Darwin'",
    "platform_system != 'Darwin'",
    "platform_system == 'Darwin'",
    "platform_system == 'Darwin'",
    "platform_system == 'Darwin'",
]

And the packages have entries like:

[[package]]
name = "torch"
version = "2.5.1"
source = { registry = "https://pypi.org/simple" }
resolution-markers = [
    "platform_system != 'Darwin'",
    "platform_system != 'Darwin'",
    "platform_system != 'Darwin'",
    "platform_system == 'Darwin'",
    "platform_system == 'Darwin'",
    "platform_system == 'Darwin'",
]

[charliermarsh]

@BurntSushi -- I think this is somehow related to #9289. When we first fork, we create three forks:

DEBUG fork: ResolverEnvironment { kind: Universal { initial_forks: [platform_system != 'Darwin', platform_system == 'Darwin'], markers: platform_system != 'Darwin', exclude: {ConflictItem { package: PackageName("project"), conflict: Extra(ExtraName("cu124")) }, ConflictItem { package: PackageName("project"), conflict: Extra(ExtraName("cpu")) }} } }
DEBUG fork: ResolverEnvironment { kind: Universal { initial_forks: [platform_system != 'Darwin', platform_system == 'Darwin'], markers: platform_system != 'Darwin', exclude: {ConflictItem { package: PackageName("project"), conflict: Extra(ExtraName("cu124")) }} } }
DEBUG fork: ResolverEnvironment { kind: Universal { initial_forks: [platform_system != 'Darwin', platform_system == 'Darwin'], markers: platform_system != 'Darwin', exclude: {ConflictItem { package: PackageName("project"), conflict: Extra(ExtraName("cpu")) }} } }

But those aren't "differentiated" in their markers.

[BurntSushi]

Hmmm. This might be a separate issue from #9289. I think the problem here is that we've traditionally assumed that forks are disjoint based on markers. But with forking based on extras, multiple forks can have the same markers. So we might be able to just de-deduplicate them?

[charliermarsh]

Maybe, I’m not sure though… The forks do represent something different than one another, but it’s not captured by the markers. Is that ok?

[BurntSushi]

It should be captured by the conflicts written to the lock file.

I guess I do wonder if perhaps the forks need their markers associated with the specific conflicts that arise for that fork during resolution.

[charliermarsh]

Yeah we may be able to dedupe. It just feels slightly off, so I'm unsure. Maybe just think on it as you solve the deeper issue around transitive deps with conflicts etc.