It seems like the combination of options passed to pip prevents usage of wheels, which makes some packages uninstallable:
This is how snapcraft fails:
creating /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/parts/nikola-source/install/usr/lib/python3/dist-packages/pip-8.1.2-py3.5.egg
Extracting pip-8.1.2-py3.5.egg to /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/parts/nikola-source/install/usr/lib/python3/dist-packages
Adding pip 8.1.2 to easy-install.pth file
Installing pip3 script to /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/parts/nikola-source/install/usr/bin
Installing pip3.5 script to /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/parts/nikola-source/install/usr/bin
Installing pip script to /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/parts/nikola-source/install/usr/bin
Installed /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/parts/nikola-source/install/usr/lib/python3/dist-packages/pip-8.1.2-py3.5.egg
Processing dependencies for pip
Finished processing dependencies for pip
python3 /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/parts/nikola-source/install/usr/bin/pip3 install --root /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/parts/nikola-source/install --install-option=--prefix=usr --requirement /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/requirements.txt
/home/ralsina/Desktop/proyectos/nikola/master/snapcraft/parts/nikola-source/install/usr/lib/python3.5/site-packages/pip-8.1.2-py3.5.egg/pip/commands/install.py:180: UserWarning: Disabling all use of wheels due to the use of --build-options / --global-options / --install-options.
cmdoptions.check_install_build_global(options)
Collecting entrypoints==0.2.2 (from -r /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/requirements.txt (line 1))
Could not find a version that satisfies the requirement entrypoints==0.2.2 (from -r /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/requirements.txt (line 1)) (from versions: )
No matching distribution found for entrypoints==0.2.2 (from -r /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/requirements.txt (line 1))
Command '['/bin/sh', '/tmp/tmpe_yi6b3p', 'python3', '/home/ralsina/Desktop/proyectos/nikola/master/snapcraft/parts/nikola-source/install/usr/bin/pip3', 'install', '--root', '/home/ralsina/Desktop/proyectos/nikola/master/snapcraft/parts/nikola-source/install', '--install-option=--prefix=usr', '--requirement', '/home/ralsina/Desktop/proyectos/nikola/master/snapcraft/requirements.txt']' returned non-zero exit status 1
And here is what is really happening, when trying to repeat the step manually:
(nikola) ralsina@clakker:~/Desktop/proyectos/nikola/master/snapcraft$ /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/parts/nikola-source/install/usr/bin/pip3 install --root /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/parts/nikola-source/install --install-option=--prefix=usr --requirement /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/requirements.txt
/home/ralsina/Desktop/proyectos/nikola/master/snapcraft/parts/nikola-source/install/usr/lib/python3.5/site-packages/pip-8.1.2-py3.5.egg/pip/commands/install.py:180: UserWarning: Disabling all use of wheels due to the use of --build-options / --global-options / --install-options.
cmdoptions.check_install_build_global(options)
Collecting entrypoints==0.2.2 (from -r /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/requirements.txt (line 1))
Could not find a version that satisfies the requirement entrypoints==0.2.2 (from -r /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/requirements.txt (line 1)) (from versions: )
No matching distribution found for entrypoints==0.2.2 (from -r /home/ralsina/Desktop/proyectos/nikola/master/snapcraft/requirements.txt (line 1))