Hash package contents / mtime to detect cache miss

[jordwalke]

Right now, if you have a local package dependency such as symlink, esy will just rebuild everything any time you do esy build. esy should hash the package contents to detect if a rebuild is actually necessary.

I believe for local file system dependencies file://blah there are other issues with not detecting changes correctly perhaps.

[andreypopp]

Should we move issues over to reasonml/esy?

[jordwalke]

Yes, perhaps I just didn't know how to do that, and wanted to avoid having them spread out over two locations (do I have to do it manually)?