In reply to @coca162:matrix.org
the issue still pretty much remains, in nix there is no way for us to edit files to update the locks, the user would see the locks are mismatching but they'd still need to do something extra

    /// Extra configuration lines for `/etc/nix.conf`
    #[cfg_attr(feature = "cli", clap(long, action = ArgAction::Append, num_args = 0.., env = "NIX_INSTALLER_EXTRA_CONF", global = true))]
    pub extra_conf: Vec<UrlOrPathOrString>,

I found something that is messed up with flakes:

1. Write src = ./.;
2. On another line write something like something = finalAttrs.src
3. Run nom build

It shows that finalAttrs.src does not match the $src that is unpacked for some reason.

The log outputs will say something like

unpacking source archive /nix/store/6vpcbgxb1lv4xb36i4z0wcns26qkqb0a-ss7yf0ysfsr45a1811bcyvpkblpnhk1q-source
source root is ss7yf0ysfsr45a1811bcyvpkblpnhk1q-source

Notice that this looks like a store path made from a store path. It seems to be, as both store paths exist. But if you write something like:

echo "${finalAttrs.src}"

you will get:

ss7yf0ysfsr45a1811bcyvpkblpnhk1q-source

Since I rely on finalAttrs.src == $src I get a derivation failure. This can be fixed if I write something like src = self; from the flake outputs.