Ccache and Travis Cache

[flippmoke]

@springmeyer is travis cache different for different compilers and different operating systems? If not we should change the ccache directory with export CCACHE_DIR=path per different environment.

[springmeyer]

Its per-compiler. You can look at the logs and see this:

$ export CASHER_DIR=$HOME/.casher
$ Installing caching utilities
attempting to download cache archive
fetching master/cache--compiler-clang.tbz
found cache
adding /home/travis/.ccache to cache

So, yeah, we should modify the cache directory. BTW, I noticed https://github.com/urho3d/Urho3D/blob/master/.travis.yml which is someone who really understands travis and there are likely some gems there.

[springmeyer]

landing here because OSX does not support caching (travis-ci/travis-ci#4011), but we should try to manually cook something up to be able to use ccache on osx.

[lightmare]

I think this can be closed. It's been established that separating caches via compiler setting in .travis.yml is clearly better than having shared cache for all jobs with separate subdirectories.

[lightmare]

Travis now automatically separates caches by OS, distro, and visible ENV vars: https://docs.travis-ci.com/user/caching/#Caches-and-build-matrices
So even the compiler hack isn't necessary anymore.

[springmeyer]

👍 thanks @lightmare