Improve Python version resolution UI #7183
Description
I just resurrected an old project (I suspect over 10 years old, changed hands entirely at one point and was rewritten from Python 2 to 3)
I managed to install it OK, but when I added another unrelated dependency, I got errors.
It turned out it was to do with an overly relaxed (and thus irreconcilable) NumPy constraint.
NumPy dropped support for Python 3.8 around v1.25, and demanded support for Python 3.10 as of v2.1.0
PDM gives a huge list of messages that hint to the user that the problem is (if they read between the lines) that you can't satisfy an unpinned numpy with a requires-python TOML config of ">=3.8,<3.13", too ambiguous
Details
(page-dewarp) louis 🚶 ~/lab/other/page-dewarp $ pdm install
WARNING: Lockfile does not exist
Updating the lock file...
INFO: Inside an active virtualenv /home/louis/lab/other/page-dewarp/.venv, reusing it.
Set env var PDM_IGNORE_ACTIVE_VENV to ignore it.
/home/louis/miniconda3/lib/python3.12/site-packages/pdm/resolver/providers.py:200: PackageWarning: Skipping numpy@2.1.1 because it requires Python>=3.10 but
the lock targets to work with Python<3.13,>=3.8. Instead, another version of numpy that supports Python<3.13,>=3.8 will be used.
If you want to install numpy@2.1.1, narrow down the `requires-python` range to include this version. For example, "<3.13,>=3.10" should work.
return self.repository.find_candidates(
/home/louis/miniconda3/lib/python3.12/site-packages/pdm/resolver/providers.py:200: PackageWarning: Skipping numpy@2.1.0 because it requires Python>=3.10 but
the lock targets to work with Python<3.13,>=3.8. Instead, another version of numpy that supports Python<3.13,>=3.8 will be used.
If you want to install numpy@2.1.0, narrow down the `requires-python` range to include this version. For example, "<3.13,>=3.10" should work.
return self.repository.find_candidates(
/home/louis/miniconda3/lib/python3.12/site-packages/pdm/resolver/providers.py:200: PackageWarning: Skipping numpy@2.0.2 because it requires Python>=3.9 but
the lock targets to work with Python<3.13,>=3.8. Instead, another version of numpy that supports Python<3.13,>=3.8 will be used.
If you want to install numpy@2.0.2, narrow down the `requires-python` range to include this version. For example, "<3.13,>=3.9" should work.
return self.repository.find_candidates(
/home/louis/miniconda3/lib/python3.12/site-packages/pdm/resolver/providers.py:200: PackageWarning: Skipping numpy@2.0.1 because it requires Python>=3.9 but
the lock targets to work with Python<3.13,>=3.8. Instead, another version of numpy that supports Python<3.13,>=3.8 will be used.
If you want to install numpy@2.0.1, narrow down the `requires-python` range to include this version. For example, "<3.13,>=3.9" should work.
return self.repository.find_candidates(
/home/louis/miniconda3/lib/python3.12/site-packages/pdm/resolver/providers.py:200: PackageWarning: Skipping numpy@2.0.0 because it requires Python>=3.9 but
the lock targets to work with Python<3.13,>=3.8. Instead, another version of numpy that supports Python<3.13,>=3.8 will be used.
If you want to install numpy@2.0.0, narrow down the `requires-python` range to include this version. For example, "<3.13,>=3.9" should work.
return self.repository.find_candidates(
/home/louis/miniconda3/lib/python3.12/site-packages/pdm/resolver/providers.py:200: PackageWarning: Skipping numpy@1.26.4 because it requires Python>=3.9 but
the lock targets to work with Python<3.13,>=3.8. Instead, another version of numpy that supports Python<3.13,>=3.8 will be used.
If you want to install numpy@1.26.4, narrow down the `requires-python` range to include this version. For example, "<3.13,>=3.9" should work.
return self.repository.find_candidates(
/home/louis/miniconda3/lib/python3.12/site-packages/pdm/resolver/providers.py:200: PackageWarning: Skipping numpy@1.26.3 because it requires Python>=3.9 but
the lock targets to work with Python<3.13,>=3.8. Instead, another version of numpy that supports Python<3.13,>=3.8 will be used.
If you want to install numpy@1.26.3, narrow down the `requires-python` range to include this version. For example, "<3.13,>=3.9" should work.
return self.repository.find_candidates(
/home/louis/miniconda3/lib/python3.12/site-packages/pdm/resolver/providers.py:200: PackageWarning: Skipping numpy@1.26.2 because it requires Python>=3.9 but
the lock targets to work with Python<3.13,>=3.8. Instead, another version of numpy that supports Python<3.13,>=3.8 will be used.
If you want to install numpy@1.26.2, narrow down the `requires-python` range to include this version. For example, "<3.13,>=3.9" should work.
return self.repository.find_candidates(
/home/louis/miniconda3/lib/python3.12/site-packages/pdm/resolver/providers.py:200: PackageWarning: Skipping numpy@1.26.1 because it requires Python<3.13,>=3.9
but the lock targets to work with Python<3.13,>=3.8. Instead, another version of numpy that supports Python<3.13,>=3.8 will be used.
If you want to install numpy@1.26.1, narrow down the `requires-python` range to include this version. For example, "<3.13,>=3.9" should work.
return self.repository.find_candidates(
/home/louis/miniconda3/lib/python3.12/site-packages/pdm/resolver/providers.py:200: PackageWarning: Skipping numpy@1.26.0 because it requires Python<3.13,>=3.9
but the lock targets to work with Python<3.13,>=3.8. Instead, another version of numpy that supports Python<3.13,>=3.8 will be used.
If you want to install numpy@1.26.0, narrow down the `requires-python` range to include this version. For example, "<3.13,>=3.9" should work.
return self.repository.find_candidates(
/home/louis/miniconda3/lib/python3.12/site-packages/pdm/resolver/providers.py:200: PackageWarning: Skipping numpy@1.25.2 because it requires Python>=3.9 but
the lock targets to work with Python<3.13,>=3.8. Instead, another version of numpy that supports Python<3.13,>=3.8 will be used.
If you want to install numpy@1.25.2, narrow down the `requires-python` range to include this version. For example, "<3.13,>=3.9" should work.
return self.repository.find_candidates(
/home/louis/miniconda3/lib/python3.12/site-packages/pdm/resolver/providers.py:200: PackageWarning: Skipping numpy@1.25.1 because it requires Python>=3.9 but
the lock targets to work with Python<3.13,>=3.8. Instead, another version of numpy that supports Python<3.13,>=3.8 will be used.
If you want to install numpy@1.25.1, narrow down the `requires-python` range to include this version. For example, "<3.13,>=3.9" should work.
return self.repository.find_candidates(
/home/louis/miniconda3/lib/python3.12/site-packages/pdm/resolver/providers.py:200: PackageWarning: Skipping numpy@1.25.0 because it requires Python>=3.9 but
the lock targets to work with Python<3.13,>=3.8. Instead, another version of numpy that supports Python<3.13,>=3.8 will be used.
If you want to install numpy@1.25.0, narrow down the `requires-python` range to include this version. For example, "<3.13,>=3.9" should work.
return self.repository.find_candidates(
/home/louis/miniconda3/lib/python3.12/site-packages/pdm/resolver/providers.py:200: PackageWarning: Skipping matplotlib@3.9.2 because it requires Python>=3.9
but the lock targets to work with Python<3.13,>=3.8. Instead, another version of matplotlib that supports Python<3.13,>=3.8 will be used.
If you want to install matplotlib@3.9.2, narrow down the `requires-python` range to include this version. For example, "<3.13,>=3.9" should work.
uv (latest version) however is showing a relatively concise and uninformative error.
If you inspect the traceback you might assume you're dealing with a setuptools issue (red herring: this is the build backend for numpy, the package doesn't use that backend).
It looks like 1.24.4 was chosen in this case, but when the python-requires was amended as PDM suggested, the uv installation succeeded.
(page-dewarp) louis 🚶 ~/lab/other/page-dewarp $ uv add msgspec
Resolved 23 packages in 39ms
error: Failed to prepare distributions
Caused by: Failed to fetch wheel: numpy==1.24.4
Caused by: Build backend failed to determine extra requires with `build_wheel()` with exit status: 1
--- stdout:
--- stderr:
Traceback (most recent call last):
File "<string>", line 8, in <module>
File "/home/louis/.cache/uv/builds-v0/.tmpr2bEaK/lib/python3.12/site-packages/setuptools/__init__.py", line 10, in <module>
import distutils.core
ModuleNotFoundError: No module named 'distutils'
---
I imagine the solution here is for uv to be on the lookout for this category of error and fail fast sooner (or at least give helpful messages before failing)?
Let me know if I haven't explained any of the setup here clearly: for reference the pathological python-requires pin was here