While using a path: URL does fix the always-changing lock file issue, I now have a different problem: whenever I change something in the sub-flake these changes are not immediately “propagated” to the parent-flake. Instead I have to recreate the lock file (or, more specifically, update the lock file entry for the sub flake). While I suppose this happens because the sub-flake is getting locked properly in the lock file, I do not think that this is desired behavior most of the time. Is there any way to make this automatic?
Edit: I guess I am running into this: More intelligent subflake locking. · Issue #6352 · NixOS/nix · GitHub