check for internet connection before uninstalling a PPA

This is not a bug report but a suggestion for improvement.

It would really make sense that ppa-purge makes a short checking of the network availability before a PPA uninstall process is started.

For example, ppa-purge is not able to remove the oibaf Mesa PPA in offline mode. Regardless of that fact, ppa-purge is trying to purge the mentioned PPA and makes the situation even worse. While some stuff is removed the original stock Mesa is not restored because the needed files cannot be downloaded. This can be confirmed for the case when ppa-purge is started from the "emergency console".

In my case I had to boot with regular settings but to the CLI aka command prompt. This can be achieved by adding a "3" to the boot parameters. For my system I also have added "xforcevesa" and "vga=791" which resulted in:

quiet splash 3 xforcevesa vga=791

After that it should be possible to boot directly to the command prompt (CLI). Log-in with username and password and then execute the corresponding ppa-purge command like:

sudo ppa-purge ppa:oibaf/graphics-drivers