VCS requires that projects build from source code that is more or less immutable except when humans really want to change it. But some projects mutate in machi

VCS requires that projects build from source code that is more or less immutable except when humans really want to change it. But some projects mutate in machine-dependent ways by the build system. Bonus points when said data is binary. I've seen CMake caches and Eclipse project files go wrong this way. Another good one is where your development project is testable only against a real database, and the schema keeps changing. Even if you could revert the schema file, you can't revert the data.