Changing a torch-installation from cu124 to cu126 removes required dependencies

Description

Switching from torch-2.x.x+cu124 to torch-2.x.x+cu126 removes important package dependencies in the lock file, which consequently leads to failures during execution. For reproducibility, one can use the pyproject.toml-file below once with x = 4 (i.e. cu124) and once with x = 6 (i.e. cu126). Using x = 4 results in the following poetry.lock-file:

poetry_124.lock.txt

Changing to x = 6 results in
poetry_126.lock.txt

In the latter, the additional nvidia-*-dependencies and triton are missing for torch in the poetry.lock-file. Somehow, poetry does not take these dependencies into account, and therefore removes them, even though they're found in the METADATA-file.

Workarounds

None known until now

Poetry Installation Method

pipx

Operating System

Observed on Win11 and Ubuntu 24.04

Poetry Version

1.8.5

Poetry Configuration

cache-dir = "C:\\Users\\~\\AppData\\Local\\pypoetry\\Cache"
experimental.system-git-client = false
installer.max-workers = null
installer.modern-installation = true
installer.no-binary = null
installer.parallel = true
keyring.enabled = true
repositories.pytorch.url = "https://download.pytorch.org/whl/cu126"
solver.lazy-wheel = true
virtualenvs.create = true
virtualenvs.in-project = null
virtualenvs.options.always-copy = false
virtualenvs.options.no-pip = false
virtualenvs.options.no-setuptools = false
virtualenvs.options.system-site-packages = false
virtualenvs.path = "{cache-dir}\\virtualenvs"  # C:\Users\~\AppData\Local\pypoetry\Cache\virtualenvs
virtualenvs.prefer-active-python = false
virtualenvs.prompt = "{project_name}-py{python_version}"
warnings.export = true

Python Sysconfig

Example pyproject.toml

[tool.poetry]
name = "torch-debug"
version = "0.1.0"
description = ""
readme = "README.md"

[tool.poetry.dependencies]
python = "^3.11"
torchvision = { version = "^0.21.0+cu12x", source = "pytorch" }
torch = { version = "^2.6.0+cu12x", source = "pytorch" }
torchaudio = { version = "^2.6.0+cu12x", source = "pytorch" }

[[tool.poetry.source]]
name = "pytorch"
url = "https://download.pytorch.org/whl/cu12x"
priority = "explicit"

[build-system]
requires = ["poetry-core"]
build-backend = "poetry.core.masonry.api"

Poetry Runtime Logs

Log files for poetry -vvv lock are attached, both for the switch from cu124 to cu126 (switch_124_126.log) and back (switch_124_126.log).

switch_124_126.log
switch_126_124.log

Start with the provided pyproject.toml and reproduce the cu124-to-cu126 switch using Poetry 1.8.5. Compare the attached poetry.lock files and read the switch_124_126.log and switch_126_124.log to trace dependency resolution. Done means the lock file retains the required nvidia-* dependencies and triton after switching CUDA variants, with the reported execution failures addressed.