Unnecessary dependency on pandas in Pypi metadata

[joshuagruenstein]

Checklist

• I have searched for similar issues.
• For Python issues, I have tested with the latest development wheel.
• I have checked the release documentation and the latest documentation (for master branch).

Describe the issue

Open3D includes the following metadata in their releases to Pypi:

Requires-Dist: setuptools (>=40.8.0)
Requires-Dist: wheel (>=0.36.0)
Requires-Dist: numpy (>=1.18.0)
Requires-Dist: ipywidgets (>=7.6.0)
Requires-Dist: pygments (>=2.7.4)
Requires-Dist: jupyter-packaging (~=0.10)
Requires-Dist: jupyterlab (==3.*,>=3.0.0)
Requires-Dist: addict
Requires-Dist: pillow (>=8.2.0)
Requires-Dist: matplotlib (>=3)
Requires-Dist: numpy (>1.15)
Requires-Dist: pandas (>=1.0)
Requires-Dist: pyyaml (>=5.4.1)
Requires-Dist: scikit-learn (>=0.21)
Requires-Dist: tqdm
Requires-Dist: pyquaternion

However, the Open3D code does not actually depend on pandas: a ctrl-f through the code-base verifies this. Having this unnecessary dependency tricks build tools like Poetry into installing unnecessary packages, and in Poetry's case leads to exponentially longer build times.

Steps to reproduce the bug

Go to https://pypi.org/pypi/open3d/json to see the metadata. ctrl-f to see the pandas dependency.

Error message

N/A

Expected behavior

This dependency should not be required, and should be removed from the metadata on Pypi.

Open3D, Python and System information

N/A: this is verifiable from any browser.

Additional information

No response

[johnthagen]

I believe related to

• Build-only dependencies are listed as required runtime dependencies #5125

Could probably be fixed more holistically/permanently by:

• Support for Python Optional Dependencies #5853

For Poetry, (which uses the JSON API) see why the JSON API has inherent problems with packages like Open3D that have different dependencies depending on the platform:

• Why does Poetry select incorrect dependencies when pip does not? python-poetry/poetry#7128

[johnthagen]

It looks like the ideal here is for Open3d to use markers (e.g. platform_system == "Windows") to explicitly mark the dependencies they have that differ between platforms.