Correct Python version is not correctly chosen

[pradal]

The Python version was chosen using CONDA_VERSION.
When CONDA_VERSION was 2, Python 2 was selected.
Otherelse, Python 3 was chosen.

However, this is not longer true. We have to specify explictly both CONDA_VERSION and PYTHON_VERSION in travis and appveyor

[pfernique]

When did it worked ? When dit it stopped ?
As you can see, your travis_ci repository is seriously late with regards to the one of StatisKit.

[pradal]

Hi Pierre, nice to read you.
I think that because we do not had before both Python 2 and Python 3 packages, evrything worked as expected.
Moreover, is old conda releases, conda 3 were mainly used with py3, while conda 2 with py2. Now this is not the case.

Do you think is usefull that we upgrade the travis-ci version? What are the changelogs?
Thanks for your advices.

[pradal]

In conda documentation with Travis, they promote the use of $TRAVIS_PYTHON_VERSION to create new conda environment.

Do you manage explicitly the Python version?

[pfernique]

I don't understand what you mean with
Moreover, is old conda releases, conda 3 were mainly used with py3, while conda 2 with py2. Now this is not the case.
In my scripts when CONDA_VERSION=2, miniconda 2 is installed and when CONDA_VERSION=3, miniconda 3 is installed.
Then, in conda builds the argument --python=${PYTHON_MAJOR}.${PYTHON_MINOR} is used

[pradal]

To clarify: You may have both Python 2 or Python 3 version with conda 2 and conda 3.
So when you create a new env, you can pass the python ersion you wante to use. Idenpendently of the version of conda.

The logic I would like is:

1. Either set CONDA_VERSION and PYTHON_VERSION as ENV variables

2. If Python_version is not defined, use CONDA_VERSION

   • PYTHON_VERSION=CONDA_VERSION

3. Or use TRAVIS_PYTHON_VERSION

[pfernique]

Well... This feature is old but I do not recommend it on Travis nor Appveyor since I encountered serious issues (wrong version of Python used in the build or as a dependency). Moreover, on CI there is no problem to install different versions of Conda. I think this is a more robust solution.

[pfernique]

But still, it could be possible to control the Conda version using PYTHON_VERSION if defined. But do we want something like 2.x, for the latest minor, and 3.6, for a previous minor ? Or simply 2 and 3 ? I will have some time next week to do so if you want.

[pradal]

I think we can just add the PYTHON_VERSION explicitly.
CONDA_VERSION is fine for me. If PYTHON_VERSION is not set, I will just define PYTHON_VERSION=$CONDA_VERSION

Otherelse, we can set PYTHON_VERSION to 2.7, 3.5, 3.6, 3.7 like done in travis.
We can even just do

PYTHON_VERSION=$TRAVIS_PYTHON_VERSION