[FIX] Windows installers: Python lookup

[ales-erjavec]

Issue

• Miniconda Installer (Windows) - handle missing/corrupted Anaconda installation #2826
• Regular 32-bit installer for Python >= 3.5 would fail to find the correct Python installation (looks for 64 bit python instead)

Description of changes

• Validate conda install layout
• Fix registry key lookup for 32 bit python >= 3.5

Includes

• Code changes
• Tests
• Documentation

[codecov-io]

Codecov Report

Merging #2827 into master will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2827      +/-   ##
==========================================
+ Coverage   81.95%   81.96%   +0.01%     
==========================================
  Files         321      321              
  Lines       54823    54841      +18     
==========================================
+ Hits        44928    44952      +24     
+ Misses       9895     9889       -6

[astaric]

Is there a way to specify the order of entries in the start menu? Currently Orange Command Prompt comes before Orange. (miniconda installer)

[ales-erjavec]

Orange comes first for me:

[astaric]

I was testing it on windows 7, I guess windows changed the default ordering since then. If Orange is listed first on recent versions of windows, it is ok

[astaric]

I have tested the miniconda stuff and it works. Not sure how to reproduce the regular installer problem though.

[ales-erjavec]

Not sure how to reproduce the regular installer problem though.

The 32-bit regular installers for Python >= 3.5 did not work at all. They would fail with "Python installation failed (cannot determine Python installation prefix)" or with a pip error "...win32.whl is not a supported wheel on this platform" depending on whether 64 bit Python was already installed.

To reproduce the error create a installer on master

./scripts/windows/build-win-installer.sh --python-version 3.6.3 --platform win32 --pip-arg={orange3==3.8.0,PyQt5,-f,https://orange.biolab.si/download/files/wheelhouse}

and try running it.

[astaric]

Thanks. As the new installers work (for me) I am merging this.