Worktrees[1] are a feature of git which allow you to check out a ref in
a different directory.
While playing around with flakes I realized that git repositories in a
worktree checkout break when trying to build a flake:
```
$ git worktree add ../nixpkgs-flakes nixpkgs-flakes
$ cd ../nixpkgs-flakes
$ nix build .#hello
error: opening directory '/home/ma27/Projects/nixpkgs-flakes/.git/refs/heads': Not a directory
```
This issue has been fixed by determining with `git rev-parse --git-common-dir`
where the actual `.git` directory is.
Please note that this issue only exists on the `flakes` branch, fetching
worktree checkouts with Nix master seems to work fine.
[1] https://git-scm.com/docs/git-worktree
This allows all supported fetchers to be used, e.g.
builtins.fetchTree {
type = "github";
owner = "NixOS";
repo = "nix";
rev = "d4df99a3349cf2228a8ee78dea320afef86eb3ba";
}
This improves reproducibility and may be faster than fetching from the
original source (especially for git/hg inputs, but probably also for
github inputs - our binary cache is probably faster than GitHub's
dynamically generated tarballs).
Unfortunately this doesn't work for the top-level flake since even if
we know the NAR hash of the tree, we don't know the other tree
attributes such as revCount and lastModified.
Fixes#3253.
Typical usage:
$ nix flake update ~/Misc/eelco-configurations/hagbard --update-input nixpkgs
to update the 'nixpkgs' input of a flake while leaving every other
input unchanged.
The argument is an input path, so you can do e.g. '--update-input
dwarffs/nixpkgs' to update an input of an input.
Fixes#2928.
Added a flag --no-update-lock-file to barf if the lock file needs any
changes. This is useful for CI systems if you're building a
checkout. Fixes#2947.
Renamed --no-save-lock-file to --no-write-lock-file. It is now a fatal
error if the lock file needs changes but --no-write-lock-file is not
given.
E.g.
$ nix flake update ~/Misc/eelco-configurations/hagbard \
--override-input 'dwarffs/nixpkgs' ../my-nixpkgs
overrides the 'nixpkgs' input of the 'dwarffs' input of the top-level
flake.
Fixes#2837.
When computing a lock file, we now respect the lock files of flake
inputs. This is important for usability / reproducibility. For
example, the 'nixops' flake depends on the 'nixops-aws' and
'nixops-hetzner' repositories. So when the 'nixops' flake is used in
another flake, we want the versions of 'nixops-aws' and
'nixops-hetzner' locked by the the 'nixops' flake because those
presumably have been tested.
This can lead to a proliferation of versions of flakes like 'nixpkgs'
(since every flake's lock file could depend on a different version of
'nixpkgs'). This is not a major issue when using Nixpkgs overlays or
NixOS modules, since then the top-level flake composes those
overlays/modules into *its* version of Nixpkgs and all other versions
are ignored. Lock file computation has been made a bit more lazy so it
won't try to fetch all those versions of 'nixpkgs'.
However, in case it's necessary to minimize flake versions, there now
are two input attributes that allow this. First, you can copy an input
from another flake, as follows:
inputs.nixpkgs.follows = "dwarffs/nixpkgs";
This states that the calling flake's 'nixpkgs' input shall be the same
as the 'nixpkgs' input of the 'dwarffs' input.
Second, you can override inputs of inputs:
inputs.nixpkgs.url = github:edolstra/nixpkgs/<hash>;
inputs.nixops.inputs.nixpkgs.url = github:edolstra/nixpkgs/<hash>;
or equivalently, using 'follows':
inputs.nixpkgs.url = github:edolstra/nixpkgs/<hash>;
inputs.nixops.inputs.nixpkgs.follows = "nixpkgs";
This states that the 'nixpkgs' input of the 'nixops' input shall be
the same as the calling flake's 'nixpkgs' input.
Finally, at '-v' Nix now prints the changes to the lock file, e.g.
$ nix flake update ~/Misc/eelco-configurations/hagbard
inputs of flake 'git+file:///home/eelco/Misc/eelco-configurations?subdir=hagbard' changed:
updated 'nixpkgs': 'github:edolstra/nixpkgs/7845bf5f4b3013df1cf036e9c9c3a55a30331db9' -> 'github:edolstra/nixpkgs/03f3def66a104a221aac8b751eeb7075374848fd'
removed 'nixops'
removed 'nixops/nixops-aws'
removed 'nixops/nixops-hetzner'
removed 'nixops/nixpkgs'
Fixes
error: derivation '/nix/store/klivma7r7h5lndb99f7xxmlh5whyayvg-zlib-1.2.11.drv' has incorrect output '/nix/store/fv98nnx5ykgbq8sqabilkgkbc4169q05-zlib-1.2.11-dev', should be '/nix/store/adm7pilzlj3z5k249s8b4wv3scprhzi1-zlib-1.2.11-dev'
As fromTOML supports \u and \U escapes, bring fromJSON on par. As JSON defaults
to UTF-8 encoding (every JSON parser must support UTF-8), this change parses the
`\u hex hex hex hex` sequence (\u followed by 4 hexadecimal digits) into an
UTF-8 representation.
Add a test to verify correct parsing, using all escape sequences from json.org.
Having a colon in the path may cause issues, and having the hash
function indicated isn't actually necessary. We now verify the path
format in the tests to prevent regressions.
This replaces the '(...)' installable syntax, which is not very
discoverable. The downside is that you can't have multiple expressions
or mix expressions and other installables.
