The manpage for `getgrouplist` says:
> If the number of groups of which user is a member is less than or
> equal to *ngroups, then the value *ngroups is returned.
>
> If the user is a member of more than *ngroups groups, then
> getgrouplist() returns -1. In this case, the value returned in
> *ngroups can be used to resize the buffer passed to a further
> call getgrouplist().
In our original code, however, we allocated a list of size `10` and, if
`getgrouplist` returned `-1` threw an exception. In practice, this
caused the code to fail for any user belonging to more than 10 groups.
While unusual for single-user systems, large companies commonly have a
huge number of POSIX groups users belong to, causing this issue to crop
up and make multi-user Nix unusable in such settings.
The fix is relatively simple, when `getgrouplist` fails, it stores the
real number of GIDs in `ngroups`, so we must resize our list and retry.
Only then, if it errors once more, we can raise an exception.
This should be backported to, at least, 2.9.x.
If a package's attribute path, description or name contains matches for any of the
regexes specified via `-e` or `--exclude` that package is excluded from
the final output.
Currently nix-build prints the "printMissing" information by default,
nix build doesn’t.
People generally don‘t notice this because the standard log-format of
nix build would not display the printMissing
output long enough to perceive the information.
This addresses https://github.com/NixOS/nix/issues/6561
The security.csm ACL is, as far as I know, never reasonable to remove, so let's add it to the ignore-list in the vanilla nix image. This makes this image usable on GKE.
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
