As suggested in #131205.
Now it's possible to pretty-print a value with `lib.generators` like
this:
with lib.generators;
toPretty { }
(withRecursion { depthLimit = 10; } /* arbitrarily complex value */)
Also, this can be used for any other pretty-printer now if needed.
When having e.g. recursive attr-set, it cannot be printed which is
solved by Nix itself like this:
$ nix-instantiate --eval -E 'let a.b = 1; a.c = a; in builtins.trace a 1'
trace: { b = 1; c = <CYCLE>; }
1
However, `generators.toPretty` tries to evaluate something until it's
done which can result in a spurious `stack-overflow`-error:
$ nix-instantiate --eval -E 'with import <nixpkgs/lib>; generators.toPretty { } (mkOption { type = types.str; })'
error: stack overflow (possible infinite recursion)
Those attr-sets are in fact rather common, one example is shown above, a
`types.<type>`-declaration is such an example. By adding an optional
`depthLimit`-argument, `toPretty` will stop evaluating as soon as the
limit is reached:
$ nix-instantiate --eval -E 'with import ./Projects/nixpkgs-update-int/lib; generators.toPretty { depthLimit = 2; } (mkOption { type = types.str; })' |xargs -0 echo -e
"{
_type = \"option\";
type = {
_type = \"option-type\";
check = <function>;
deprecationMessage = null;
description = \"string\";
emptyValue = { };
functor = {
binOp = <unevaluated>;
name = <unevaluated>;
payload = <unevaluated>;
type = <unevaluated>;
wrapped = <unevaluated>;
};
getSubModules = null;
getSubOptions = <function>;
merge = <function>;
name = \"str\";
nestedTypes = { };
substSubModules = <function>;
typeMerge = <function>;
};
}"
Optionally, it's also possible to let `toPretty` throw an error if the
limit is exceeded.
m68k was recently added for Linux and none, but NetBSD also supports
m68k. Nothing will build yet, but I want to make sure we at least
encode the existence of NetBSD support for every applicable
architecture we support for other operating systems.
In 2d45a62899, the submodule type
description was amended with the freeformType description. This causes
all the modules passed to the submodule to be evaluated once on their
own, without any extra definitions from the config section. This means
that the specified modules need to be valid on their own, without any
undeclared options.
This commit adds a test that evaluates a submodules option description,
which would trigger the above problem for one of the tests, if it were
not fixed by this commit as well.
This is done because the next commit makes option evaluation a bit more
strict, which would also trigger this test failure, even though it's not
related to the change at all.
These are all the architectures supported by Nixpkgs on other
platforms, that are also supported by NetBSD. (So I haven't added
any architectures that are new to Nixpkgs here, even though NetBSD
supports some that we don't have.)
I recently wrote some Nix code where I wrongly set a value to an option
which wasn't an actual option, but an attr-set of options. The mistake I
made can be demonstrated with an expression like this:
{
foo = { lib, pkgs, config, ... }: with lib; {
options.foo.bar.baz = mkOption {
type = types.str;
};
config.foo.bar = 23;
};
}
While it wasn't too hard to find the cause of the mistake for me, it was
necessary to have some practice in reading stack traces from the module
system since the eval-error I got was not very helpful:
error: --- TypeError --------------------------------------------------------- nix-build
at: (323:25) in file: /nix/store/3nm31brdz95pj8gch5gms6xwqh0xx55c-source/lib/modules.nix
322| foldl' (acc: module:
323| acc // (mapAttrs (n: v:
| ^
324| (acc.${n} or []) ++ f module v
value is an integer while a set was expected
(use '--show-trace' to show detailed location information)
I figured that such an error can be fairly confusing for someone who's
new to NixOS, so I decided to catch this case in th `byName` function in
`lib/modules.nix` by checking if the value to map through is an actual
attr-set. If not, a different error will be thrown.
PPC64 supports two ABIs: ELF v1 and v2.
ELFv1 is historically what GCC and most packages expect, but this is
changing because musl outright does not work with ELFv1. So any distro
which uses musl must use ELFv2. Many other platforms are moving to ELFv2
too, such as FreeBSD (as of v13) and Gentoo (as of late 2020).
Since we use musl extensively, let's default to ELFv2.
Nix gives us the power to specify this declaratively for the entire
system, so ELFv1 is not dropped entirely. It can be specified explicitly
in the target config, e.g. "powerpc64-unknown-linux-elfv1". Otherwise the
default is "powerpc64-unknown-linux-elfv2". For musl,
"powerpc64-unknown-linux-musl" must use elfv2 internally to function.
Previously the .enable option was used to encode the condition as well,
which lead to some oddness:
- In order to encode an assertion, one had to invert it
- To disable a check, one had to mkForce it
By introducing a separate .check option this is solved because:
- It can be used to encode assertions
- Disabling is done separately with .enable option, whose default can be
overridden without a mkForce
Previously this option was thought to be necessary to avoid infinite
recursion, but it actually isn't, since the check evaluation isn't fed
back into the module fixed-point.
- These symbols can be confusing for those not familiar with them
- There's no harm in making these more obvious
- Terminals may not print them correctly either
Also changes the function argument printing slightly to be more obvious
`toHex` converts the given positive integer to a string of the hexadecimal
representation of that integer. For example:
```
toHex 0 => "0"
toHex 16 => "10"
toHex 250 => "FA"
```
`toBase base i` converts the positive integer `i` to a list of it
digits in the given `base`. For example:
```
toBase 10 123 => [ 1 2 3 ]
toBase 2 6 => [ 1 1 0 ]
toBase 16 250 => [ 15 10 ]
```
The semantic difference between `encode` and `to` is not apparent.
Users are likely to confuse both functions (which leads to unexpected
error messages about the wrong types). Like in `generators.nix`, all
functions should be prefixed by `to`.
Furthermore, converting to a string depends on the target context. In
this case, it’s a POSIX shell, so we should name it that (compare
`escapeShellArg` in `strings.nix`).
We can later add versions that escape for embedding in e.g. python
scripts or similar.
Fix the broken test in https://github.com/NixOS/nixpkgs/pull/77416
Apparently hydra uses `nix-build lib/tests/release.nix` to run all
tests, where IFD isn't allowed. Fortunately we can get around this with
builtins.toFile, which doesn't require IFD, but still can test the
properties we want.
This adds a new utility to intelligently convert Nix records to
command line options to reduce boilerplate for simple use cases and to
also reduce the likelihood of malformed command lines
`pipe` is a useful operator for creating pipelines of functions.
It works around the usual problem of e.g. string operations becoming
deeply nested functions.
In principle, there are four different ways this function could be
written:
pipe val [ f1 .. fn ]
pipe val [ fn .. f1 ]
compose [ f1 .. fn ] val
compose [ fn .. f1 ] val
The third and fourth form mirror composition of functions, they would
be the same as e.g. `(f1 << f2 << f3 .. << fn) val`.
However, it is not clear which direction the list should have (as one
can see in the second form, which is the most absurd.
In order not to confuse users, we decide for the most “intuitive”
form, which mirrors the way unix pipes work (thus the name `pipe`).
The flow of data goes from left to right.
Co-Authored-By: Silvan Mosberger <infinisil@icloud.com>
This reverts commit ce2f74df2c.
Doubles are treated as -darwin here, to provide some consistency.
There is some ambiguity between “x86_64-darwin” and “i686-darwin”
which could refer to binaries linked between iOS simulator or real
macOS binaries. useiOSPrebuilt can be used to determine which to use,
however.
This commit changes the `mkAliasOptionModule` function to make sure that
the priority for the aliased option is propagated to the non-aliased
option.
This also affects the `mkRenamedOptionModule` function in a similar
fashion.
This also removes the `mkAliasOptionModuleWithPriority` function, since
its functionality is now subsumed by `mkAliasOptionModule`.
This change was recommended by @nbp:
https://github.com/NixOS/nixpkgs/pull/53397#discussion_r245487432
This commit adds a function `mkAliasOptionModuleWithPriority`. This
function will make an alias to an existing option and copy over the
priority.
This functionality is needed for PRs like #53041. In that case
`nixos-generate-config` added an option to `hardware-configuration.nix`
with `mkDefault`. That option was then changed and an alias created for
the old name.
The end user should be able to set the non-alias option in their
`configuration.nix` and have everything work correctly. Without this
function, the priority for the option won't be copied over correctly
and the end-user will get a message saying they have the same option
set to two different values.
This has been not touched in 6 years. Let's remove it to cause less
problems when adding new cross-compiling infrastructure.
This also simplify gcc significantly.
toPath has confusing semantics and is never necessary; it can always
either just be omitted or replaced by pre-concatenating `/.`. It has
been marked as "!!! obsolete?" for more than 10 years in a C++
comment, hopefully removing it will let us properly deprecate and,
eventually, remove it.
Assigning a list of 10 or more elements to an option having the type
`loaOf a` produces a configuration value that is not honoring the
order of the original list. This commit fixes this and a related issue
arising when 10 or more lists are merged into this type of option.
So far, `mkValueString` defaulted to `toString`,
which is a bad match for most configuration file formats,
especially because how booleans are formatted.
This also improves error messages for unsupported types.
Add a test to codify the formatting.
Existing "mips64el" should be "mipsel".
This is just the barest minimum so that nixpkgs can recognize them as
systems - although required for building individual derivations onto
MIPS boards, it is not sufficient if you want to actually build nixos on
those targets
This means the generation of values can now be influenced, even down from e.g.
an INI generator.
Breaks the interface of `mkKeyValueDefault` to match its interface to other
generator functions. It might me sensible to rename `mkKeyValue` and
`mkKeyValueSet` to conform to the `toX`-style of generator functions.
With `builtins.functionArgs` we can get some information if the first argument
is an attrset and whether the contained fields have default values. Encode that
into the pretty-printed lambda.
The old hard-coded lists are now used to test system parsing.
In the process, make an `assertTrue` in release lib for eval tests; also
use it in release-cross
This is based on a prototype Nicolas B. Pierron worked on during a
discussion we had at FOSDEM.
A new version with a workaround for problems of the reverted original.
Discussion: https://github.com/NixOS/nixpkgs/commit/3f2566689
