Problem 1

The first problem I ran into when trying to run rospy with Python 3.14 is that it wouldn't build. I chased down errors and found that it was trying to utilize a different version of python to do the building than the version we wanted to actually run with. I think this just generally creates a lot of potential for compatibility issues.

In fact, my version of Ubuntu 22.04 doesn't even have python available. I dunno if that was a bug or is part of Python2 being discontinued, but it caused the changed code, when reached, to error. When I manually set it to python3.10 I got new kinds of errors related to pip and all that. I think it generally is a bad idea to use Python 3.10 to construct a virtualenv and gather all the dependencies for a Python3.14 project.

Instead of calling python by string name, we use the target version of Python, which is passed in from CMakeLists.txt via argparse. To do this in a number of functions, we move python to the constructor args and make it an instance member.

Problem 2

Once I started using this further, I found that there is a further problem with setuptools missing. This came when trying to depend on locus_py. I found that setuptools is no-longer pre-installed in venvs (Changed in version 3.12: setuptools is no longer a core venv dependency.)

I hacked away at venv.py to install setuptools as part of preinstall. Also went to a newer version of pip and pip-tools. Pretty sure this breaks Python2 support.

Problem 3

When depending on tycho_py I ran into install failure issues with numpy. Meson complains: ../meson.build:41:12: ERROR: Python dependency not found

I tried updating numpy in tycho_py requirements.txt to the latest version: 2.3.4 and get a version resolution error:

ERROR: Ignored the following versions that require a different python version: 2.3.0 Requires-Python >=3.11; 2.3.1 Requires-Python >=3.11; 2.3.2 Requires-Python >=3.11; 2.3.3 Requires-Python >=3.11; 2.3.4 Requires-Python >=3.11
ERROR: Could not find a version that satisfies the requirement numpy==2.3.4 (from versions: 1.3.0, 1.4.1, 1.5.0, 1.5.1, 1.6.0, 1.6.1, 1.6.2, 1.7.0, 1.7.1, 1.7.2, 1.8.0, 1.8.1, 1.8.2, 1.9.0, 1.9.1, 1.9.2, 1.9.3, 1.10.0.post2, 1.10.1, 1.10.2, 1.10.4, 1.11.0, 1.11.1, 1.11.2, 1.11.3, 1.12.0, 1.12.1, 1.13.0, 1.13.1, 1.13.3, 1.14.0, 1.14.1, 1.14.2, 1.14.3, 1.14.4, 1.14.5, 1.14.6, 1.15.0, 1.15.1, 1.15.2, 1.15.3, 1.15.4, 1.16.0, 1.16.1, 1.16.2, 1.16.3, 1.16.4, 1.16.5, 1.16.6, 1.17.0, 1.17.1, 1.17.2, 1.17.3, 1.17.4, 1.17.5, 1.18.0, 1.18.1, 1.18.2, 1.18.3, 1.18.4, 1.18.5, 1.19.0, 1.19.1, 1.19.2, 1.19.3, 1.19.4, 1.19.5, 1.20.0, 1.20.1, 1.20.2, 1.20.3, 1.21.0, 1.21.1, 1.21.2, 1.21.3, 1.21.4, 1.21.5, 1.21.6, 1.22.0, 1.22.1, 1.22.2, 1.22.3, 1.22.4, 1.23.0, 1.23.1, 1.23.2, 1.23.3, 1.23.4, 1.23.5, 1.24.0, 1.24.1, 1.24.2, 1.24.3, 1.24.4, 1.25.0, 1.25.1, 1.25.2, 1.26.0, 1.26.1, 1.26.2, 1.26.3, 1.26.4, 2.0.0, 2.0.1, 2.0.2, 2.1.0, 2.1.1, 2.1.2, 2.1.3, 2.2.0, 2.2.1, 2.2.2, 2.2.3, 2.2.4, 2.2.5, 2.2.6)
ERROR: No matching distribution found for numpy==2.3.4

Along with log errors before this, I'm pretty sure the issue is that the installer is still using Python 3.10 to build a Python 3.14 virtualenv.

Testing

You can test this with this repo: https://github.com/ablakey/rospypypi/tree/main Though you may have to add additionally complex dependencies to figure out what else is breaking where.