In some contexts, we don’t want to have to build the whole i686 stdenv
just to use the x86_64 nvidia driver. It’s hard to know ahead of time
what we want, so it’s best to leave this as an overridable option.
I have been using the main example of the spaCy web page for testing
updates of spacy (and its transitive dependencies). Let's convert this
into a proper test to take out manual testing.
An easy-to-make mistake when declaring e.g. a submodule is the accidental
confusion of `options` and `config`:
types.submodule {
config = {
foo = mkOption { /* ... */ };
};
}
However the error-message
The option `[definition 1-entry 1].foo' defined in `<expr.nix>' does not exist.
is fairly unhelpful because it seems as the options are declared at the
first sight. In fact, it took a colleague and me a while to track down such
a mistake a few days ago and we both agreed that this should be somehow caught
to save the time we spent debugging the module in question.
At first I decided to catch this error in the `submodules`-type directly
by checking whether `options` is undeclared, however this becomes fairly
complicated as soon as a submodule-declaration e.g. depends on existing
`config`-values which would've lead to some ugly `builtins.tryExec`-heuristic.
This patch now simply checks if the option's prefix has any options
defined if a point in evaluation is reached where it's clear that the
option in question doesn't exist. This means that this patch doesn't
change the logic of the module system, it only provides a more detailed
error in certain cases:
The option `[definition 1-entry 1].foo' defined in `<expr.nix>' does not exist.
However it seems as there are no options defined in [definition 1-entry 1]. Are you sure you've
declared your options properly? This happens if you e.g. declared your options in `types.submodule'
under `config' rather than `options'.
If `qemu-vm.nix` is imported, the option `virtualisation.qemu.consoles`
should be set to make sure that the machine's output isn't rendered on
the graphical window of QEMU.
This is needed when interactively running a NixOS test or in conjunction
with `nixos-build-vms(8)`.
The patch 2578557530 tries to only do this
if the option actually exists, however this condition used to be always
false since `options` wasn't imported in the module and pointed to
`lib.options` due to the `with lib;`-clause.
