most modules can be evaluated for their documentation in a very
restricted environment that doesn't include all of nixpkgs. this
evaluation can then be cached and reused for subsequent builds, merging
only documentation that has changed into the cached set. since nixos
ships with a large number of modules of which only a few are used in any
given config this can save evaluation a huge percentage of nixos
options available in any given config.
in tests of this caching, despite having to copy most of nixos/, saves
about 80% of the time needed to build the system manual, or about two
second on the machine used for testing. build time for a full system
config shrank from 9.4s to 7.4s, while turning documentation off
entirely shortened the build to 7.1s.
some options have default that are best described in prose, such as
defaults that depend on the system stateVersion, defaults that are
derivations specific to the surrounding context, or those where the
expression is much longer and harder to understand than a simple text
snippet.
The first one doesn't make any sense because the directory where the
init binary resides does not contain other tools we need like
systemd-escape.
The second one doesn't make sense either because the errors are already
ignored.
This reverts commit 57961d2b83, reversing
changes made to b04f913afc.
(I.e. this reverts PR #141192.)
While well-intended, this change does unfortunately introduce very
serious regressions that are especially disruptive/noticeable on desktop
systems (e.g. users of Sway will loose their graphical session when
running "nixos-rebuild switch").
Therefore, this change has to be reverted ASAP instead of trying to fix
it in "production".
Note: An updated version should be extensively discussed, reviewed, and
tested before re-landing this change as an earlier version also had to
be reverted for the exact same issues [0].
Fix: #146727
[0]: https://github.com/NixOS/nixpkgs/pull/73871#issuecomment-559783752
By using the new extendModules function to produce the specialisations,
we avoid reimplementing the eval-config.nix logic in reverse and fix
cross compilation support for specialisations in the process.
This makes the order of operations the same in dry-activate and a "true"
activate. Also fixes the indentation I messed up and drop a useless
unlink() call (we are already unlinking that file earlier).
The previous logic failed to detect that units were socket-activated
when the socket was stopped before switch-to-configuration was run. This
commit fixes that and also starts the socket in question.
The first FIXME is removed because it doesn't make sense to use
/proc/1/exe since that points to a directory that doesn't have all tools
the activation script needs (like systemd-escape).
The second one is removed because there is already no error handling
(compare with the restart logic where the return code is checked).
This commit changes a lot more that you'd expect but it also adds a lot
of new testing code so nothing breaks in the future. The main change is
that sockets are now restarted when they change. The main reason for
the large amount of changes is the ability of activation scripts to
restart/reload units. This also works for socket-activated units now,
and honors reloadIfChanged and restartIfChanged. The two changes don't
really work without each other so they are done in the one large commit.
The test should show what works now and ensure it will continue to do so
in the future.
When cross-compiling, we can't run the runtime shell to check syntax
if it's e.g. for a different architecture. We have two options here.
We can disable syntax checking when cross compiling, but that risks
letting errors through. Or, we can do what I've done here, and change
the syntax check to use stdenv's shell instead of the runtime shell.
This requires the stdenv shell and runtime shell to be broadly
compatible, but I think that's so ingrained in Nixpkgs anyway that
it's fine. And this way we avoid conditionals that check for cross.
The primary use case is tools like sops-nix and agenix to restart units
when secrets change. There's probably other reasons to restart units as
well and a nice thing to have in general.
Since 03eaa48 added perl.withPackages, there is a canonical way to
create a perl interpreter from a list of libraries, for use in script
shebangs or generic build inputs. This method is declarative (what we
are doing is clear), produces short shebangs[1] and needs not to wrap
existing scripts.
Unfortunately there are a few exceptions that I've found:
1. Scripts that are calling perl with the -T switch. This makes perl
ignore PERL5LIB, which is what perl.withPackages is using to inform
the interpreter of the library paths.
2. Perl packages that depends on libraries in their own path. This
is not possible because perl.withPackages works at build time. The
workaround is to add `-I $out/${perl.libPrefix}` to the shebang.
In all other cases I propose to switch to perl.withPackages.
[1]: https://lwn.net/Articles/779997/
