the fix to extendDerivation in #140051 unwittingly worsened eval performance by
quite a bit. set elements alone needed over 1GB extra after the change, which
seems disproportionate to how small it was. if we flip the logic used to
determine which outputs to install around and keep a "this one exactly" flag in
the specific outputs instead of a "all of them" in the root we can avoid most
of that cost.
if extendDerivation is called on something that already had extendDerivation
called on it (eg a mkDerivation result) the second call will set
outputUnspecified=true on every output by way of propagating attributes of the
full derivation to the individual outputs. this in turn causes buildEnv--and
thus nix-shell and environment.systemPackages--to install every output of such a
derivation even when only a specific output was requested, which renders the
point of multiple outputs moot. this happens in python modules (see #139756),
though it seems that tcl and possibly others should also be affected.
I'm working on a project that involves running a virtual machine
monitor program, which creates a control socket in the project
directory (because it doesn't make sense to put it anywhere else).
This obviously isn't part of the source of my program, so I think
cleanSource should filter it out.
Consider a derivation a value to be serialized.
nix-repl> lib.generators.toGitINI { hello = { drv = pkgs.hello; }; }
error: evaluation aborted with the following error message: 'generators.mkValueStringDefault: attrsets not supported: <derivation /nix/store/533q15q67sl6dl0272dyi7m7w5pwkkjh-hello-2.10.drv>'
Fixes #137390
The current implementation of the concatStringsSep fallback references
concatStrings whcih is just a partial application of concatStringsSep,
forming a circular dependency. Although this will almost never be
encountered as (assuming the user does not explicitly trigger it):
1. the or operator will short circuit both in lazy and strict
evaluation
2. this can only occur in Nix versions prior to 1.10
which is not compatible with various nix operations as of 2.3.15
However it is still important if scopedImport is used or the builtins
have been overwritten. lib.foldl' is used instead of builtins.foldl'
as the foldl' primops was introduced in the same release as concatStringsSep.
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.
The message I originally implemented here was to catch a mixup of
`config' and `options' in a `types.submodule'[1]. However it looks
rather weird for a wrongly declared top-level option.
So I decided to throw
error: The option `foo' does not exist. Definition values:
- In `<unknown-file>':
{
bar = {
_type = "option";
type = {
_type = "option-type";
...
It seems as you're trying to declare an option by placing it into `config' rather than `options'!
for an expression like
with import ./lib;
evalModules {
modules = [
{
foo.bar = mkOption {
type = types.str;
};
}
];
}
[1] fa30c9abed
When having a bogus declaration such as
{ lib, ... }:
{
foo.bar = mkOption {
type = types.str;
};
}
the evaluation will terminate with a not-so helpful
error: stack overflow (possible infinite recursion)
To make sure a useful error is still provided, I added a `depthLimit` of
`10` which should be perfectly sufficient to `toPretty` when it's used
in an error-case for `showDefs`.
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.
- Remove inheritance of `lists.fold` as it isn't used anywhere.
- Inherit `foldl'` for consistency as only `cartesianProductOfSets` explicitly
reference lib.
- Inline `foldr` to generate nested attrs instead of using `listToAttrs` and `tail`.
This allows checking e.g. stdenv.hostPlatform.isGnu, just like isMusl
or isUClibc. It was already possible to check for glibc with
stdenv.hostPlatform.libc == "glibc", but when that doesn't line up
with how every other platform check works, this is apparently
sufficiently non-obvious that we've ended up with stuff like adding
glibc.static if !isMusl, which is obviously wrong.
This regressed in 9c213398b3
The recursiveUpdate gave the platform both gcc.cpu and gcc.arch attrs
instead of only gcc.cpu. This is invalid; gcc configuration fails with:
```
Switch "--with-arch" may not be used with switch "--with-cpu"
```
So we revert to using `//` to retain only gcc.cpu
(which is more specific than the processor arch).
Trying to create a simple flake with input:
```
{
inputs.nixpkgs-lib.url = "github:NixOS/nixpkgs?dir=lib";
outputs = {nixpkgs-lib, ...}: { };
}
```
Fails when trying to evaluate the nixpkgs-lib flake with an error like:
```
error: getting status of '/nix/store/xxxx-source/lib/lib': No such file or directory
(use '--show-trace' to show detailed location information)
```
Allows for distinction of licenses that are unfree overall but do grant the
right to redistribute. Defaults to the freeness of the license.
Note: Many unfree but are redistributable licenses aren't marked as such.
I expect that to be fixed in a distributed manner over time.
Closes https://github.com/NixOS/nixpkgs/pull/97789
Previously, if a derivation without a `drvPath` was handled, an error
would be thrown:
nix-repl> lib.generators.toPretty {} { type = "derivation"; }
error: attribute 'drvPath' missing, at /home/infinisil/src/nixpkgs/lib/generators.nix:251:24
With this commit it doesn't anymore:
nix-repl> lib.generators.toPretty {} { type = "derivation"; }
"<derivation ???>"
This matches what `nix repl` outputs:
nix-repl> { type = "derivation"; }
«derivation ???»
For an option definition that uses `lib.options.mergeEqualOption`
underneath, like `types.anything`, an error is thrown when multiple
functions are assigned, indicating that functions can't be compared for
equivalence:
error: The option `test' has conflicting definition values:
- In `xxx': <function>
- In `xxx': <function>
(use '--show-trace' to show detailed location information)
However, the error message didn't use the correct files. While above
error indicates that both definitions are in the xxx file, that's in
fact not true. Above error was generated with
options.test = lib.mkOption {
type = lib.types.anything;
};
imports = [
{
_file = "yyy";
test = y: y;
}
{
_file = "xxx";
test = x: x;
}
];
With this change, the error uses the correct file locations:
error: The option `test' has conflicting definition values:
- In `xxx': <function>
- In `yyy': <function>
(use '--show-trace' to show detailed location information)
so the underlaying use case of the preceding commit is so
generic, that we gain a lot in reasoning to give it an
appropriate name.
As the comment states:
image media needs to override host config short of mkForce
