Relative 'path:' flake inputs now use the containing flake's
InputAccessor. This has the following implications:
* They're no longer locked in the lock file.
* They don't cause an additional copy to the store.
* They can reference the containing directory (i.e. a subflake can
have an input '../foo', so long as it doesn't go outside the
top-level containing flake).
Note: this is not a complete fix for subflake handling, since the lock
file currently makes it ambiguous what the containing flake is. We'll
probably need to add another field to the lock file for that.
Fixes#6352.
User on Matrix reported install problems which presented as
"vifs:editing error" which we traced back to vim griping about an
existing swap file. When opened interactively, it did this:
E325: ATTENTION
Found a swap file by the name "/etc/.fstab.swp"
owned by: root dated: Sön Apr 24 16:54:10 2022
file name: /private/etc/fstab
modified: YES
user name: root host name: MBP.local
process ID: 1698
While opening file "/etc/fstab"
dated: Sön Apr 24 16:56:27 2022
NEWER than swap file!
...
To quote Eelco in #5867:
> Unfortunately we can't do
>
> evalSettings.pureEval.setDefault(false);
>
> because then we have to do the same in main.cc (where
> pureEval is set to true), and that would allow pure-eval
> to be disabled globally from nix.conf.
Instead, a command should specify that it should be impure by
default. Then, `evalSettings.pureEval` will be set to `false;` unless
it's overridden by e.g. a CLI flag.
In that case it's IMHO OK to be (theoretically) able to override
`pure-eval` via `nix.conf` because it doesn't have an effect on commands
where `forceImpureByDefault` returns `false` (i.e. everything where pure
eval actually matters).
Closes#5867
The git fetcher code used to dereference the (potentially empty) `ref`
input attribute. This was magically working, probably because the
compiler somehow outsmarted us, but is now blowing up with newer nixpkgs
versions.
Fix that by not trying to access this field while we don't know for sure
that it has been defined.
Fix#6554
