Cache Behaviour

Hello,

This is a general question which might be helpful to write up in the README. What exactly determines:

1. When the cache can be stored?
2. When the cache can be used?

For my current workflow (https://github.com/spinicist/QUIT/actions), building vcpkg and dependencies takes >30 minutes, whereas building my project takes only 5. Hence caching is a real game-changer. I have observed the following:

1. The cache is only stored at the end of the run in the “post vcpkg” phase, if every phase was successful. This was very frustrating for my build, because for every typo in my .yml file I had to wait 30 minutes for the dependencies to build. Would it be possible to store the cache directly after finishing a successful vcpkg+dependencies build instead?
2. I kicked off a build with a tag, which will create a Release with my setup. I did this via (approximately) git commit -m "A release build"; git tag a_tag; git push && git push origin a_tag. This starts two builds almost simultaneously in Github Actions, one for the first push and one for the tag. The first build correctly picked up the cached vcpkg information, but the tag did not. Why did the tag build not pick up the cache?

Thanks again for providing these actions, they’re very useful.

[spinicist]

Hello - finally had a chance to try. Sadly it looks like it doesn’t play well with Manifest mode? Since originally raising this I’ve swapped to manifest mode and it looks like all my dependencies are being rebuilt at the configure. Will continue discussion over on #53

[spinicist]

Other projects are getting in the way of trying this - I will let you know when I finally get a chance but I’m sure it will be good!