Amend or clarify interaction between build.tools.python and conda.environment

[astrojuanlu]

If build.tools.python is specified with a non-conda version at the same time that conda.environment is present, the build fails. See for example:

https://readthedocs.org/projects/salishsea-nowcast/builds/14996913/

/home/docs/.asdf/installs/python/3.9.7/bin/python: can't open file '/home/docs/checkouts/readthedocs.org/user_builds/salishsea-nowcast/checkouts/latest/env': [Errno 2] No such file or directory

which corresponds to this configuration file:

version: 2

build:
  os: ubuntu-20.04
  tools:
    python: "3.9"

conda:
  environment: envs/environment-rtd.yaml

# Only build HTML and JSON formats
formats: []

We should either produce a better error message if this combination is not possible, or reconcile the two options.

(Thanks @douglatornell for the report 🙏🏽)

[humitos]

I think it makes sense to fail the build with a validation error in the config file saying something like "If conda.environment is specified, you have to use build.tools.python with mambaforge or miniconda"

[astrojuanlu]

xref https://stackoverflow.com/q/69774313

[esennesh]

xref https://stackoverflow.com/q/69774313

My thanks for finding my question and documenting what's going on!

[DanielChaseButterfield]

I would also like this amended or clarified somewhere in the documentation. I was getting the following error, with no clear way of how to fix it:

python -mvirtualenv $READTHEDOCS_VIRTUALENV_PATH
usage: virtualenv [--version] [--with-traceback] [-v | -q] [--read-only-app-data] [--app-data APP_DATA] [--reset-app-data] [--upgrade-embed-wheels] [--discovery {builtin}] [-p py] [--try-first-with py_exe]
[--creator {builtin,cpython3-posix,venv}] [--seeder {app-data,pip}] [--no-seed] [--activators comma_sep_list] [--clear] [--no-vcs-ignore] [--system-site-packages] [--symlinks | --copies] [--no-download | --download]
[--extra-search-dir d [d ...]] [--pip version] [--setuptools version] [--wheel version] [--no-pip] [--no-setuptools] [--no-wheel] [--no-periodic-update] [--symlink-app-data] [--prompt prompt] [-h]
dest
virtualenv: error: the following arguments are required: dest
SystemExit: 2

Although the Stack overflow post exists (https://stackoverflow.com/questions/69774313/why-does-rtd-run-python-env-create-instead-of-conda-env-create-when-building), I don't know what I would have done if I didn't find it.

[benjaoming]

This seems at the very least like a simple docs issue: I also just stumbled on it while wondering if conda needs to be listed in build.tools or not.

[st-bender]

Hi,
Just observed this too and had to search the issues for a fix. Please fix the docs, especially since build.image has been deprecated in favour of build.os and build.tools:
https://blog.readthedocs.com/use-build-os-config/

Edit: this is where I'd be looking for a hint:
https://docs.readthedocs.io/en/stable/config-file/v2.html#conda
Just add a sentence that build.tools.python needs to be one of the conda/mamba ones.

Thanks.