pip -d tries (and fails) to download packages meant for wrong platform

[Michael-Kuritzky]

Description

Hi,

I have a build system which uses pip -d to download packages along with their dependencies. Recently I ran into an error when I tried to update one of the packages I use (details below), which seems to stem from pip -d trying to grab unnecessary dependencies (meant for a different platform).

Some details:
I'm using Windows, and running pip -d --platform manylinux1_x86_64 to download packages meant for Linux.
I ran into the problem when I tried to switch from azure-identity==1.3.1 to azure-identity==1.10.0.
azure-identity==1.10.0 depends, among other things, on msal-extensions<2.0.0,>=0.3.0 which, in turn, depends on portalocker<3,>=1.6 for Windows-based platforms and portalocker<3,>=1.0 for non-Windows-based platforms.
So far, so good.
However, all the versions of portalocker from 1.6.0 seem to have a Windows-specific dependency on a Windows-specific package named pywin32 (pywin32>=226; platform_system == "Windows"). That in itself should not be a problem, but pip -d seems to ignore the "windows-specificness" of this dependency and tries to download it - an operation which fails since there are, naturally, no versions of pywin32 meant for Linux.

Expected behavior

I expect pip -d --platform manylinux1_x86_64 to ignore Windows-specific dependencies.

pip version

22.2.2

Python version

3.7.9

OS

Microsoft Windows 11 Enterprise Version 10.0.22000 Build 22000

How to Reproduce

1. Install Python on a Windows machine (I have Python 3.7.9, but I doubt it matters in this case).
2. Update pip to 22.2.2.
3. Run the following command: py -m pip download azure-identity==1.10.0 -d "C:\Temp\PipRepro" --platform "manylinux1_x86_64" --python-version "3.8" --only-binary=:all: --retries 3 --timeout 60
   (you can substitute some other directory instead of "C:\Temp\PipRepro", of course.
4. pip complains that it "Cannot install msal-extensions because these package versions have conflicting dependencies.".

Output

Collecting azure-identity==1.10.0
  Using cached azure_identity-1.10.0-py3-none-any.whl (134 kB)
Collecting six>=1.12.0
  File was already downloaded c:\temp\piprepro\six-1.16.0-py2.py3-none-any.whl
Collecting cryptography>=2.5
  File was already downloaded c:\temp\piprepro\cryptography-3.3.2-cp36-abi3-manylinux1_x86_64.whl
Collecting azure-core<2.0.0,>=1.11.0
  File was already downloaded c:\temp\piprepro\azure_core-1.25.0-py3-none-any.whl
Collecting msal<2.0.0,>=1.12.0
  File was already downloaded c:\temp\piprepro\msal-1.18.0-py2.py3-none-any.whl
Collecting msal-extensions<2.0.0,>=0.3.0
  Using cached msal_extensions-1.0.0-py2.py3-none-any.whl (19 kB)
Collecting requests>=2.18.4
  File was already downloaded c:\temp\piprepro\requests-2.28.1-py3-none-any.whl
Collecting typing-extensions>=4.0.1
  File was already downloaded c:\temp\piprepro\typing_extensions-4.3.0-py3-none-any.whl
Collecting cffi>=1.12
  File was already downloaded c:\temp\piprepro\cffi-1.14.6-cp38-cp38-manylinux1_x86_64.whl
Collecting PyJWT[crypto]<3,>=1.0.0
  File was already downloaded c:\temp\piprepro\PyJWT-2.4.0-py3-none-any.whl
Collecting portalocker<3,>=1.6
  Using cached portalocker-2.5.1-py2.py3-none-any.whl (15 kB)
Collecting pycparser
  File was already downloaded c:\temp\piprepro\pycparser-2.21-py2.py3-none-any.whl
Collecting portalocker<3,>=1.6
  Using cached portalocker-2.5.0-py2.py3-none-any.whl (15 kB)
  Using cached portalocker-2.4.0-py2.py3-none-any.whl (16 kB)
  Using cached portalocker-2.3.2-py2.py3-none-any.whl (15 kB)
  Using cached portalocker-2.3.1-py2.py3-none-any.whl (15 kB)
  Using cached portalocker-2.3.0-py2.py3-none-any.whl (15 kB)
  Using cached portalocker-2.2.1-py2.py3-none-any.whl (15 kB)
  Using cached portalocker-2.2.0-py2.py3-none-any.whl (15 kB)
  Using cached portalocker-2.1.0-py2.py3-none-any.whl (13 kB)
  Using cached portalocker-2.0.0-py2.py3-none-any.whl (11 kB)
  Using cached portalocker-1.7.1-py2.py3-none-any.whl (10 kB)
  Using cached portalocker-1.7.0-py2.py3-none-any.whl (14 kB)
  Using cached portalocker-1.6.0-py2.py3-none-any.whl (14 kB)
INFO: pip is looking at multiple versions of cffi to determine which version is compatible with other requirements. This could take a while.
Collecting cffi>=1.12
  Using cached cffi-1.14.5-cp38-cp38-manylinux1_x86_64.whl (411 kB)
INFO: pip is looking at multiple versions of six to determine which version is compatible with other requirements. This could take a while.
Collecting six>=1.12.0
  Using cached six-1.15.0-py2.py3-none-any.whl (10 kB)
INFO: pip is looking at multiple versions of msal-extensions to determine which version is compatible with other requirements. This could take a while.
Collecting msal-extensions<2.0.0,>=0.3.0
  Using cached msal_extensions-0.3.1-py2.py3-none-any.whl (18 kB)
  Using cached msal_extensions-0.3.0-py2.py3-none-any.whl (16 kB)
INFO: pip is looking at multiple versions of msal to determine which version is compatible with other requirements. This could take a while.
Collecting msal<2.0.0,>=1.12.0
  Using cached msal-1.17.0-py2.py3-none-any.whl (79 kB)
  Using cached msal-1.16.0-py2.py3-none-any.whl (78 kB)
INFO: pip is looking at multiple versions of msal-extensions to determine which version is compatible with other requirements. This could take a while.
  Using cached msal-1.15.0-py2.py3-none-any.whl (77 kB)
  Using cached msal-1.14.0-py2.py3-none-any.whl (75 kB)
INFO: This is taking longer than usual. You might need to provide the dependency resolver with stricter constraints to reduce runtime. See https://pip.pypa.io/warnings/backtracking for guidance. If you want to abort this run, press Ctrl + C.
  Using cached msal-1.13.0-py2.py3-none-any.whl (67 kB)
  Using cached msal-1.12.0-py2.py3-none-any.whl (66 kB)
INFO: pip is looking at multiple versions of cryptography to determine which version is compatible with other requirements. This could take a while.
Collecting cryptography>=2.5
  Using cached cryptography-3.3.1-cp36-abi3-manylinux1_x86_64.whl (2.7 MB)
INFO: pip is looking at multiple versions of msal to determine which version is compatible with other requirements. This could take a while.
INFO: This is taking longer than usual. You might need to provide the dependency resolver with stricter constraints to reduce runtime. See https://pip.pypa.io/warnings/backtracking for guidance. If you want to abort this run, press Ctrl + C.
  Using cached cryptography-3.3-cp36-abi3-manylinux1_x86_64.whl (2.7 MB)
  Using cached cryptography-3.2.1-cp35-abi3-manylinux1_x86_64.whl (2.6 MB)
  Using cached cryptography-3.2-cp35-abi3-manylinux1_x86_64.whl (2.6 MB)
  Using cached cryptography-3.1.1-cp35-abi3-manylinux1_x86_64.whl (2.6 MB)
  Using cached cryptography-3.1-cp35-abi3-manylinux1_x86_64.whl (2.6 MB)
  Using cached cryptography-3.0-cp35-abi3-manylinux1_x86_64.whl (2.7 MB)
INFO: pip is looking at multiple versions of cryptography to determine which version is compatible with other requirements. This could take a while.
  Using cached cryptography-2.9.2-cp35-abi3-manylinux1_x86_64.whl (2.7 MB)
  Using cached cryptography-2.9.1-cp35-abi3-manylinux1_x86_64.whl (2.7 MB)
  Using cached cryptography-2.9-cp35-abi3-manylinux1_x86_64.whl (2.7 MB)
  Using cached cryptography-2.8-cp34-abi3-manylinux1_x86_64.whl (2.3 MB)
  Using cached cryptography-2.7-cp34-abi3-manylinux1_x86_64.whl (2.3 MB)
Collecting asn1crypto>=0.21.0
  Using cached asn1crypto-1.5.1-py2.py3-none-any.whl (105 kB)
INFO: This is taking longer than usual. You might need to provide the dependency resolver with stricter constraints to reduce runtime. See https://pip.pypa.io/warnings/backtracking for guidance. If you want to abort this run, press Ctrl + C.
Collecting cryptography>=2.5
  Using cached cryptography-2.6.1-cp34-abi3-manylinux1_x86_64.whl (2.3 MB)
  Using cached cryptography-2.5-cp34-abi3-manylinux1_x86_64.whl (2.4 MB)
INFO: pip is looking at multiple versions of azure-core to determine which version is compatible with other requirements. This could take a while.
Collecting azure-core<2.0.0,>=1.11.0
  Using cached azure_core-1.24.2-py3-none-any.whl (178 kB)
  Using cached azure_core-1.24.1-py3-none-any.whl (178 kB)
  Using cached azure_core-1.24.0-py3-none-any.whl (178 kB)
  Using cached azure_core-1.23.1-py3-none-any.whl (178 kB)
  Using cached azure_core-1.23.0-py3-none-any.whl (179 kB)
  Using cached azure_core-1.22.1-py3-none-any.whl (178 kB)
  Using cached azure_core-1.21.1-py2.py3-none-any.whl (178 kB)
INFO: pip is looking at multiple versions of azure-core to determine which version is compatible with other requirements. This could take a while.
  Using cached azure_core-1.21.0-py2.py3-none-any.whl (178 kB)
  Using cached azure_core-1.20.1-py2.py3-none-any.whl (177 kB)
  Using cached azure_core-1.20.0-py2.py3-none-any.whl (176 kB)
  Using cached azure_core-1.19.1-py2.py3-none-any.whl (176 kB)
  Using cached azure_core-1.19.0-py2.py3-none-any.whl (176 kB)
INFO: This is taking longer than usual. You might need to provide the dependency resolver with stricter constraints to reduce runtime. See https://pip.pypa.io/warnings/backtracking for guidance. If you want to abort this run, press Ctrl + C.
  Using cached azure_core-1.18.0-py2.py3-none-any.whl (166 kB)
  Using cached azure_core-1.17.0-py2.py3-none-any.whl (165 kB)
  Using cached azure_core-1.16.0-py2.py3-none-any.whl (163 kB)
  Using cached azure_core-1.15.0-py2.py3-none-any.whl (138 kB)
  Using cached azure_core-1.14.0-py2.py3-none-any.whl (136 kB)
  Using cached azure_core-1.13.0-py2.py3-none-any.whl (133 kB)
  Using cached azure_core-1.12.0-py2.py3-none-any.whl (130 kB)
  Using cached azure_core-1.11.0-py2.py3-none-any.whl (127 kB)
INFO: pip is looking at multiple versions of <Python from Requires-Python> to determine which version is compatible with other requirements. This could take a while.
INFO: pip is looking at multiple versions of azure-identity to determine which version is compatible with other requirements. This could take a while.
ERROR: Cannot install msal-extensions because these package versions have conflicting dependencies.

The conflict is caused by:
    portalocker 1.7.1 depends on pywin32!=226; platform_system == "Windows"
    portalocker 1.7.0 depends on pywin32!=226; platform_system == "Windows"
    portalocker 1.6.0 depends on pywin32!=226; platform_system == "Windows"

To fix this you could try to:
1. loosen the range of package versions you've specified
2. remove package versions to allow pip attempt to solve the dependency conflict

ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/topics/dependency-resolution/#dealing-with-dependency-conflicts

Code of Conduct

• I agree to follow the PSF Code of Conduct.

[sbidoul]

This looks like a duplicate of #10050.