Platform-Specific Dependencies in requirements.in Not Working as Expected with --universal

[ewianda]

Description:
When specifying platform-specific dependencies in requirements.in for optimum[onnxruntime] and optimum[onnxruntime-gpu], the generated requirements.txt file consolidates dependencies inappropriately. Specifically, optimum[onnxruntime-gpu]; sys_platform == 'linux' and optimum[onnxruntime]; sys_platform == 'darwin' results in optimum[onnxruntime,onnxruntime]==1.18; sys_platform == 'linux' in the output requirements.txt, which causes the Darwin platform dependency to be ignored.

Steps to Reproduce:

1. Create a requirements.in file with the following lines:

   optimum[onnxruntime-gpu]; sys_platform == 'linux'
   optimum[onnxruntime]; sys_platform == 'darwin'
   

2. Run uv pip compile --universal requirements.in to generate requirements.txt.
3. Open the resulting requirements.txt.

Expected Behavior:
requirements.txt should list both platform-specific dependencies separately, like:

optimum[onnxruntime-gpu]==1.18; sys_platform == 'linux'
optimum[onnxruntime]==1.18; sys_platform == 'darwin'

Actual Behavior:
The generated requirements.txt incorrectly merges dependencies, resulting in:

optimum[onnxruntime,onnxruntime-gpu]==1.18; sys_platform == 'linux'

This line omits the macOS (Darwin) dependency entirely.

Environment:

• uv version: 0.4.30

• Operating System: Linux

[charliermarsh]

I can guess at what's going on here, thanks.

[ewianda]

Hi @charliermarsh , I just tested the fix, and it works, but for one anomaly.

 echo -e "optimum[onnxruntime]; sys_platform == 'darwin'\noptimum[onnxruntime-gpu]; sys_platform == 'linux'" | cargo run --  pip compile --universal --no-strip-extras  - | grep optimum
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.34s
     Running `target/debug/uv pip compile --universal --no-strip-extras -`
 
optimum==1.23.3 ; sys_platform == 'darwin' or sys_platform == 'linux'
optimum[onnxruntime]==1.23.3 ; sys_platform == 'darwin'
optimum[onnxruntime-gpu]==1.23.3 ; sys_platform == 'linux'  

The extra optimum==1.23.3 ; sys_platform == 'darwin' or sys_platform == 'linux' seems unnecessary

[charliermarsh]

I saw that, but I think it's acceptable personally.