takluyver
commented
2 years ago Good question. Pynsist is built on top of NSIS, and it's not something Pynsist changes, so I did a bit of googling about why NSIS is that way.
The basic answer seems to be that the way NSIS installers run doesn't make it easy to undo the steps that have already been done, so 'just' cancelling would leave a half-complete installation which it may not be easy to uninstall again (e.g. it might not have written the uninstaller exe). In theory, you can write NSIS code to enable the cancel button and try to undo the partial installation, but it'd be a real pain to test. It's probably better for everyone just to let the installation complete, and then go and uninstall it again.
- http://forums.winamp.com/showthread.php?t=317977
- https://nsis.sourceforge.io/InstFiles_Cancel_-_Allowing_a_user_to_cancel_installation_during_InstFiles
I think making an MSI based installer would get round this, because that's based on a system that will record & roll back changes. I did play around with using WiX at one point, but it's a very different system to NSIS, so making a Python wrapper for it would be a completely new project.
mattiatantardini
Hi, I've noticed that the cancel button is not clickable once the installation is launched (the step after setting the installation path). Not a real issue, but it is annoying in case of heavy installations if you did some mistake in setting the path.