Inconsistence between download_datasets and get_samples_dir

[marcboulle]

Description

Lorsque l'on utilise la fonction download_datasets, les examples sont downloadés sous C:\Users\<userid>\khiops_data\samples.
Mais quand on demande ou sont les example par get_samples_dir, on obtient C:\Users\Public\khiops_data\samples.

Context

Version 11.0.0
OS: Windows

[popescu-v]

On Windows operating systems, when the KHIOPS_SAMPLES_DIR environment variable is not set, the KhiopsLocalRunner instance initializes, via the ._initialize_default_samples_dir method, the (default) samples directory (which can subsequently be retrieved via the .samples_dir runner property), via the following strategy:

1. if the %PUBLIC% environment variable is set, and its value denotes an existing and accessible directory (or remote path), then the default samples directory is set to %PUBLIC%\khiops_data\samples;
2. else, the default samples directory is set to %USERPROFILE%\khiops_data\samples.

On the other hand, the kh-download-datasets command uses the the download_datasets helper function, which, on Windows operating systems, follows a different strategy:

1. Systematically download the datasets to the %USERPROFILE%\khiops_data\samples directory, if it exists; if the directory doesn't exist, then create it and download the datasets therein.

Note that, on Windows as well as on Linux / macOS operating systems, the KHIOPS_SAMPLES_DIR environment variable is ignored by the donwload_datasets function, which always uses the default samples directory (computed according to a different strategy on Windows - see above).

The goal of this issue is to make download_datasets follow a strategy that is coherent with the KhiopsLocalRunner's _initialize_default_samples_dir method:

1. If KHIOPS_SAMPLES_DIR is defined, then use it as a target samples directory path; if it doesn't exist, then create it;
2. else, on Windows, if %PUBLIC% is defined, then use %PUBLIC%\khiops_data\samples as target directory; if it does not exist, then create it;
3. else, on Windows, use %USERPROFILE%\khiops_data\samples as target directory; if it does not exist, then create it.

On Linux, download_dataset should:

1. If KHIOPS_SAMPLES_DIR is defined, then use it as a target samples directory path; if it doesn't exist, then create it;
2. else, use $HOME/khiops_data/samples as target directory; if it doesn't exist, then create it.