Passing the elaborated system defeats what pkgs/top-level/default.nix
tries to do: Pass only the original args and let defaults be inferred.
The underlying problem is that lib.systems.elaborate can not deal with
arbitrary overrides, but will often return an inconsistent system
description when partially overriding some values. This becomes most
prominent if trying to override an already elaborated system.
It creates interoperability issues that can not be reconciled by
`lib` or maintainers of projects that use the Nixpkgs library.
Occasionally, end users may be able to solve the problems they run
into, but most are not prepared to deal with this set of problems,
nor should they be.
Typical conflict:
- User wants to propagate their own lib, because it has some function
they like to use throughout their projects
- Project maintainer requires the project's lib to be used
No sane language uses a single namespace for combining all the things.
(Arguably not even C with its extensive use of prefixing)
Meanwhile, in Nix, all symbols are first class variables. We don't even
have the concept of a global top-level namespace to pour everything into.
With `lib` you can try to approximate that, I get the appeal of its
apparent simplicity, but since `lib` can't be global, we just don't even
get that apparent simplicity.
I apologize for not offering concrete solutions to this in the text.
The manuals are limited to reference documentation.
Alternatives - of which we have multiple - are best provided in
task-oriented documentation, e.g. nix.dev.
It's not the longest-open PR (May 28, 2023 -> Jan 22, 2025) but it took a while. This PR introduces a unified approach to implementing build helpers that support fixed-point arguments and bring such support to existing build helpers.
Before this patch, code like this would break generate invalid XML:
lib.generators.toPlist {} "ab<cd"
That's obviously bad, since the call to toPlist often happens through
indirection, as is the case in e.g. the nix-darwin project. A user might
not realize that they have to escape the strings.
This patch adds the argument 'escape' to lib.generators.plist and emits
a warning if it is not set to true. In a future release, this behavior
should become the default.
I have also added a note for future maintainers, in case I forget to
actually remove the deprecated functionality in a future release.
Include the system string in the error message to give a bit more context to
the user.
Co-authored-by: Wolfgang Walther <wolfgangwalther@users.noreply.github.com>
After final improvements to the official formatter implementation,
this commit now performs the first treewide reformat of Nix files using it.
This is part of the implementation of RFC 166.
Only "inactive" files are reformatted, meaning only files that
aren't being touched by any PR with activity in the past 2 months.
This is to avoid conflicts for PRs that might soon be merged.
Later we can do a full treewide reformat to get the rest,
which should not cause as many conflicts.
A CI check has already been running for some time to ensure that new and
already-formatted files are formatted, so the files being reformatted here
should also stay formatted.
This commit was automatically created and can be verified using
nix-build a08b3a4d19.tar.gz \
--argstr baseRev b32a094368
result/bin/apply-formatting $NIXPKGS_PATH
After final improvements to the official formatter implementation,
this commit now performs the first treewide reformat of Nix files using it.
This is part of the implementation of RFC 166.
Only "inactive" files are reformatted, meaning only files that
aren't being touched by any PR with activity in the past 2 months.
This is to avoid conflicts for PRs that might soon be merged.
Later we can do a full treewide reformat to get the rest,
which should not cause as many conflicts.
A CI check has already been running for some time to ensure that new and
already-formatted files are formatted, so the files being reformatted here
should also stay formatted.
This commit was automatically created and can be verified using
nix-build a08b3a4d19.tar.gz \
--argstr baseRev 78e9caf153
result/bin/apply-formatting $NIXPKGS_PATH
