In https://github.com/NixOS/nixpkgs/issues/333734 it was noticed that
executing the list-generations with sudo would fail. The reason was,
that the variable $PAGER was set, but empty.
${PAGER:cat} only has the default of cat if PAGER is unset, but it will
not default to cat if the variable is empty instead.
One way of fixing this would have been to change it to ${PAGER:-cat},
but since a pager requires pressing an additional key to exit, it is a
bit annoying in the first place, so it was removed instead.
Lore overrides have been included with binlore's source up to now, but
this hasn't worked very well. (It isn't as easy to self-service for
people working in nixpkgs, and its use of partial pnames for matching
breaks down around some edge cases like version numbers appearing
early in perl pnames, or multiple packages having identical pnames.)
Most nixos-rebuild commands support a relative flake path, however
`repl` uses `builtins.getFlake` and that requires an absolute path. So
ensure we pass an absolute path to it, providing UX consistency. Only do
so when the path exists in order to passthrough URLs as-is.
pkgs.lib and lib need not match, so prefer the one that the modules get.
For example:
```nix
nix-repl> :lf nixpkgs
nix-repl> (lib.nixosSystem { modules = [ ({ lib, ... }: assert lib?nixosSystem; { nixpkgs.hostPlatform = "x86_64-linux"; }) ]; }).pkgs.lib?nixosSystem
false
```
The code is backwards compatible, for the case where you evaluate a
config whose nixpkgs doesn't have the preceding commit yet.
This solves again the problem solved by 09fd207cb8.
To quote:
> We always want to use `ssh -t` to force PTY allocation as there may be
> interactive SSH prompts like trusting unknown hosts.
However, the creation of a pseudoterminal causes the remote stdout and stderr
to point to the same tty, resulting in a single stream in the ssh client,
which breaks other usages of ssh, such as `--build-host`.
Hence, this commit only sets the flag for invocations that need it -
or would need it if sudo were disabled. That should help with development
and gives a somewhat more consistent user experience.
Apologies to the non-flake users; your repl isn't quite as fancy,
but at least evaluates your config exactly as you would expect,
unlike flakes which are only evaluated impurely for now.
This is a hint that mentions the feature #105910 but that is not yet
merged. This is very confusing and since it there is no progress with
that merge we should remove the reference
Right now, running `nixos-rebuild switch` in a remote system via SSH may
put the system in an unusable state by restarting services (e.g.:
network ones like systemd-networkd.service) during the update. This will
cause the SSH to lose access to the TTY, stopping the process entirely.
This commit wraps up the call to `switch-to-configuration` inside a
systemd-run call, making the switch resiliant against TTY loss, since it
will allocate its own TTY. For the user this should be entirely
transparent though, with the only visible change is that the
`switch-to-configuration` messages will be logged through journalctl
(e.g.: `journalctl -u nixos-rebuild-switch-to-configuration`).
