Occasionally, `nix-build --check` is fairly helpful and I'd like to be
able to use this feature for flakes that need to be built with `nix
build` as well.
I think this better captures the intent of what's going on: we either
have an opaque store path, or a drv path with some outputs.
Having this structure will also help us support CA derivations: we'll
have to allow the outpath paths to be optional, so the structure we gain
now makes up for the structure we loose then.
That is, the commands 'nix path-info nixpkgs#hello' and 'nix path-info
/nix/store/00ls0qi49qkqpqblmvz5s1ajl3gc63lr-hello-2.10.drv' now do the
same thing (i.e. build the derivation and operate on the output store
path, rather than the .drv path).
This allows you to refer to an input from another flake. For example,
$ nix run --inputs-from /path/to/hydra nixpkgs#hello
runs 'hello' from the 'nixpkgs' inputs of the 'hydra' flake.
Fixes#3769.
E.g.
$ nix run nixpkgs#hello
error: --- Error ---------- nix
flake 'flake:nixpkgs' does not provide attribute 'apps.x86_64-linux.hello' or 'hello'
instead of
$ nix run nixpkgs#hello
error: --- Error ---------- nix
flake 'flake:nixpkgs' does not provide attribute 'hello'
This fixes an issue where lockfile generation was not idempotent:
after updating a lockfile, a "follows" node would end up pointing to a
new copy of the node, rather than to the original node.
The initial contents of the flake is specified by the
'templates.<name>' or 'defaultTemplate' output of another flake. E.g.
outputs = { self }: {
templates = {
nixos-container = {
path = ./nixos-container;
description = "An example of a NixOS container";
};
};
};
allows
$ nix flake init -t templates#nixos-container
Also add a command 'nix flake new', which is identical to 'nix flake
init' except that it initializes a specified directory rather than the
current directory.
The attributes previously stored in TreeInfo (narHash, revCount,
lastModified) are now stored in Input. This makes it less arbitrary
what attributes are stored where.
As a result, the lock file format has changed. An entry like
"info": {
"lastModified": 1585405475,
"narHash": "sha256-bESW0n4KgPmZ0luxvwJ+UyATrC6iIltVCsGdLiphVeE="
},
"locked": {
"owner": "NixOS",
"repo": "nixpkgs",
"rev": "b88ff468e9850410070d4e0ccd68c7011f15b2be",
"type": "github"
},
is now stored as
"locked": {
"owner": "NixOS",
"repo": "nixpkgs",
"rev": "b88ff468e9850410070d4e0ccd68c7011f15b2be",
"type": "github",
"lastModified": 1585405475,
"narHash": "sha256-bESW0n4KgPmZ0luxvwJ+UyATrC6iIltVCsGdLiphVeE="
},
The 'Input' class is now a dumb set of attributes. All the fetcher
implementations subclass InputScheme, not Input. This simplifies the
API.
Also, fix substitution of flake inputs. This was broken since lazy
flake fetching started using fetchTree internally.
This completes flakerefs using the registry (e.g. 'nix<TAB>' => 'nix
nixpkgs') and flake output attributes by evaluating the flake
(e.g. 'dwarffs#nix<TAB>' => 'dwarffs#nixosModules').
InstallableValue has children InstallableFlake and InstallableAttrPath, but InstallableFlake was overriding toDerivations, and usage was changed so that InstallableFlake didn't need cmd. So these changes were made:
InstallableValue::toDerivations() -> InstalllableAttrPath::toDerivations()
InstallableValue::cmd -> InstallableAttrPath::cmd
InstallableValue uses state instead of cmd
toBuildables() and toDerivations() were made abstract
In particular, doing 'nix build /path/to/dir' now works if
/path/to/dir is not a Git tree (it only has to contain a flake.nix
file).
Also, 'nix flake init' no longer requires a Git tree (but it will do a
'git add flake.nix' if it's a Git tree)
