The vast majority of CI jobs to build the lib tests are caused by
changes in the maintainer list. In this case, we currently run the full
test-suite which takes 3-4 minutes. By moving the maintainers and teams
tests out of the test-with-nix file, we save almost all of that.
Building only those two tests on a change is almost instant. This only
works, because we previously enabled cachix for the workflow.
Note, that these tests are not actually run with both nix versions, even
though they were listed in the "test with specific nix version" file.
That's because we only differ in the nix version run *inside* the
sandbox, but not doing the outer build.
Since this file seems to be re-used by NixOS/nix' CI, this is
technically a small loss in coverage for that repo, but nixpkgs CI
considerations outweigh that. But because of this, I left the other
non-nix-version-specific tests in that file.
This patch adds `lib.repoRevToName` function that generalizes away most of the
code used for derivation name generation by `fetch*` functions (`fetchzip`,
`fetchFromGitHub`, etc, except those which are delayed until latter commits
for mass-rebuild reasons).
It's first argument controls how the resulting name will look (see below).
Since `lib` has no equivalent of Nixpkgs' `config`, this patch adds
`config.fetchedSourceNameDefault` option to Nixpkgs and then re-exposes
`lib.repoRevToName config.fetchedSourceNameDefault` expression as
`pkgs.repoRevToNameMaybe` which is then used in `fetch*` derivations.
The result is that different values of `config.fetchedSourceNameDefault` now
control how the `src` derivations produced by `fetch*` functions are to be
named, e.g.:
- `fetchedSourceNameDefault = "source"` (the default):
```
$ nix-instantiate -A fuse.src
/nix/store/<hash>-source.drv
```
- `fetchedSourceNameDefault = "versioned"`:
```
$ nix-instantiate -A fuse.src
/nix/store/<hash>-libfuse-2.9.9-source.drv
```
- `fetchedSourceNameDefault = "full"`:
```
$ nix-instantiate -A fuse.src
/nix/store/<hash>-libfuse-2.9.9-github-source.drv
```
See the documentation of `config.fetchedSourceNameDefault` for more info.
I believe this change is wrong both theoretically and practically.
Theoretically, `null` is available on every platform, because
`buildInputs = [ null ];` always succeeds and never throws a platform
availability error. `null` should be handled consistently with packages
that have no explicit list of supported platforms, as it of course
has no such list itself.
Practically, we use `null` to represent libraries that are always
present on a platform and do not require a library (for instance,
because they are part of `libc` or the macOS SDK). This has been
used for a long time by `libintl` (on all non‐glibc platforms),
and is also now used by `libGL` and friends on Darwin. This change
broke the check SDL3 does for OpenGL availability on Darwin, causing
<https://github.com/NixOS/nixpkgs/issues/407056>, which had to be
worked around by <https://github.com/NixOS/nixpkgs/pull/409525>.
Both `libintl` and `libGL` should count as available on platforms
where their functionality is part of the standard build environment,
and a package that is completely unavailable and whose functionality
cannot be expected should not use `null`, as it should result in
errors if used in a dependency list on an unsupported platform.
I accept that overriding with `null` is often a useful way to disable
dependencies that don’t have explicit feature flags, but I do not
think that making it work better with feature flags conditioned on
availability is worth the inconsistency and problems caused by this
change. Packages can instead expose the relevant feature flags as
arguments that default to the `lib.meta.availableOn` check or, if they
want to keep an “override the dependency to `null`” interface,
insert an explicit `pkg != null && …` check.
Additionally, the pull request was merged over a week after all
breaking changes were restricted for the 25.05 release. I believe that
the potential problems of dealing with the effects of this change for
an entire release cycle – the first release cycle where `libGL` is
`null` on Darwin, a change I made before the deadline and before this
change to `lib.meta.availableOn` – offset the risks of backporting
this revert at such a late stage.
It will cause overrides to backwards‐incompatibly revert to the
behaviour they had before the change, but since such overrides were
not possible until a few weeks ago, I hope that is an acceptable risk
compared to the potential issues leaving this in the release can
cause, given that it was merged after the deadline and has already
broken an existing construction in Nixpkgs.
This reverts commit 9338d924db.
The `importApply` docs reference using the `_key` attr along with
`importApply` or `_file`, however the actual attr name used by the
module system is `key`.
The new implementation of `mapAttrsToList` is simpler than the previous one, avoiding an extra string conversion. Benchmarking shows a slight performance improvement. See the discussion here: https://discourse.nixos.org/t/another-implementation-of-mapattrstolist
Additionally, I searched nixpkgs for expressions equivalent to the old `mapAttrsToList` and replaced them with direct calls to the new implementation.
To fix overriding packages that checks for platform compatibility, like pipewire.
`pipewire` contains the following logic to enable support for ldac depending on library platform compatibility:
```nix
ldacbtSupport = lib.meta.availableOn stdenv.hostPlatform ldacbt
```
Which is used later in the expression to create a Meson flag:
```nix
(lib.mesonEnable "bluez5-codec-ldac" (bluezSupport && ldacbtSupport))
```
This means that attempting to build `pipewire` without `ldacbt` like:
```nix
pipewire.override {
ldacbt = null;
}
```
will fail because the the Meson flag indicates the feature should be enabled, but the library is passed to `buildInputs` as `null`.
