The old string format is a holdover from the pre JSON days. It is not
friendly to users who need to get the information out of it.
Also introduce the sort of versioning we have for derivation for this
format too.
Add a `secretKeyFiles` URI parameter in the store URIs receiving a
coma-separated list of Nix signing keyfiles.
For instance:
nix copy --to "file:///tmp/store?secret-keys=/tmp/key1,/tmp/key2" \
"$(nix build --print-out-paths nixpkgs#hello)"
The keys passed through this new store URI parameter are merged with
the key specified in the `secretKeyFile` parameter, if any.
We'd like to rotate the signing key for cache.nixos.org. To simplify
the transition, we'd like to sign the new paths with two keys: the new
one and the current one. With this, the cache can support nix
configurations only trusting the new key and legacy configurations
only trusting the current key.
See https://github.com/NixOS/rfcs/pull/149 for more informations
behind the motivation.
I think it is bad for these reasons when `tests/` contains a mix of
functional and integration tests
- Concepts is harder to understand, the documentation makes a good
unit vs functional vs integration distinction, but when the
integration tests are just two subdirs within `tests/` this is not
clear.
- Source filtering in the `flake.nix` is more complex. We need to
filter out some of the dirs from `tests/`, rather than simply pick
the dirs we want and take all of them. This is a good sign the
structure of what we are trying to do is not matching the structure
of the files.
With this change we have a clean:
```shell-session
$ git show 'HEAD:tests'
tree HEAD:tests
functional/
installer/
nixos/
```
