Conda Python runtimes fail with init_sys_streams: Bad file descriptor after launching Conda-based R runtime on macOS

Thanks for the report @ChenHingO!

The init_sys_streams ... Bad file descriptor error means Python's stdin/stdout/stderr aren't available when the process launches. I don't think we've seen this specific failure before so we'll need some more information to help us debug.

The fact that system Python 3.9 works but Conda 3.13/3.14 doesn't is interesting.

A few more things that would help:

1. Have you used the same Conda envs successfully in another tool (VS Code, Jupyter, etc.)?
2. Does the Conda env work in the terminal?

   conda activate dev
   python -c "import sys; print(sys.version); print(sys.executable)"
   

3. How was Conda installed: Anaconda, Miniconda, Miniforge?
4. If you can, please also run the Developer: Runtime Startup Diagnostics command from the Command Palette (Cmd+Shift+P), then copy the full output and share it here.

Originally posted by @seeM in #13580

No source file or test is identified in the issue. Start by checking the Conda environment in the terminal with the supplied Python command, compare it with other tools, and run Developer: Runtime Startup Diagnostics. The issue currently defines investigation and information gathering rather than a confirmed fix.