Currently it's not possible to determine the reason why a package is
unavailable without evaluating nixpkgs multiple times with different
settings. eg.
nix-repl> :p android-studio.meta
{ available = false; broken = false; unfree = true; unsupported = true; ... }
The following snippet is an example that uses this information to query
the availability information of all packages in nixpkgs, giving an
overview of all the packages currently marked as broken, etc.
{ pkgs }:
with import <nixpkgs/lib>;
let
mapPkgs =
let mapPkgs' = path: f: mapAttrs (n: v:
let result = builtins.tryEval (v ? meta); in
if !result.success then {} else
if isDerivation v then f (path ++ [n]) v else
if isAttrs v && v.recurseForDerivations or false then mapPkgs' (path ++ [n]) f v else
{}
);
in mapPkgs' [];
getMeta = path: drv:
if drv.meta ? available then
let meta = {
pkg = concatStringsSep "." path;
inherit (drv.meta) broken unfree unsupported insecure;
};
in builtins.trace meta.pkg meta
else {};
metaToList = attrs: flatten (map (v: if v ? pkg then v else metaToList v) (attrValues attrs));
in metaToList (mapPkgs getMeta pkgs)
There were two issues:
* builtins.getEnv was called deep into the nixpkgs tree making it hard
to discover. This is solved by moving the call into
pkgs/top-level/impure.nix
* when the config was explicitly set by the user to false, it would
still try and load the environment variable. This meant that it was
not possible to guarantee the same outcome on two different systems.
A package's meta.license can either be a single license or a list. The
code to check config.whitelistedLicenses and config.blackListedLicenses
wasn't handling this, nor was the showLicense function.
Hydra's page showing evaluation errors is about a mile long, showing
buckets of user-friendly errors, like this:
in job ‘seyren.aarch64-linux’:
Package ‘oraclejre-8u191’ in /nix/store/fa9zzkbljkvdavwzirkrr5irg25ymbjl-source/pkgs/development/compilers/oraclejdk/jdk-linux-base.nix:71 has an unfree license (‘unfree’), refusing to evaluate.
a) For `nixos-rebuild` you can set
{ nixpkgs.config.allowUnfree = true; }
in configuration.nix to override this.
b) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
{ allowUnfree = true; }
to ~/.config/nixpkgs/config.nix.
in job ‘jetbrains.webstorm.x86_64-linux’:
Package ‘webstorm-2018.3.1’ in /nix/store/fa9zzkbljkvdavwzirkrr5irg25ymbjl-source/pkgs/applications/editors/jetbrains/default.nix:230 has an unfree license (‘unfree’), refusing to evaluate.
a) For `nixos-rebuild` you can set
{ nixpkgs.config.allowUnfree = true; }
in configuration.nix to override this.
b) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
{ allowUnfree = true; }
to ~/.config/nixpkgs/config.nix.
This makes it extremely hard to find actual issues in the output. This
patch set makes the output much more condensed in Hydra:
Failed to evaluate nifticlib-2.0.0: «unsupported»: is not supported on ‘x86_64-apple-darwin’
Failed to evaluate dmd-2.081.2: «unsupported»: is not supported on ‘aarch64-unknown-linux-gnu’
Failed to evaluate dmdBuild-2.081.2: «unsupported»: is not supported on ‘aarch64-unknown-linux-gnu’
Failed to evaluate ldc-1.11.0: «unsupported»: is not supported on ‘aarch64-unknown-linux-gnu’
Failed to evaluate ldcBuild-1.11.0: «unsupported»: is not supported on ‘aarch64-unknown-linux-gnu’
Failed to evaluate ldc-0.17.5: «unsupported»: is not supported on ‘aarch64-unknown-linux-gnu’
Failed to evaluate ldcBuild-0.17.5: «unsupported»: is not supported on ‘aarch64-unknown-linux-gnu’
This will make the list much easier to re-use, eg. for `nixosTests`
The drawback is that this approaches makes the
```
nix-build release.nix -A tests.opensmtpd.x86_64-linux
```
command about twice as slow (3s to 6s): it now has to evaluate `nixpkgs`
once for each architecture, instead of just having the hardcoded list of
tests that allowed to say “ok just evaluate for x86_64-linux”.
On the other hand, complete evaluation of `release.nix` should be much
faster because we no longer import `nixpkgs` for each test: testing with
the following command went from 30s to 18s, and that's just for a few
tests.
```
time nix-instantiate --eval --strict nixos/release.nix -A tests.nat
```
I initially wanted to test on the whole `release.nix`, but there are too
many broken tests and it takes too long to eval them all, especially
compared to the fact that the current implementation breaks some setup.
Given developers can just `nix-build nixos/tests/my-test.nix`, it sounds
like an overall win.
Rationale
---------
Currently, tests are hard to discover. For instance, someone updating
`dovecot` might not notice that the interaction of `dovecot` with
`opensmtpd` is handled in the `opensmtpd.nix` test.
And even for someone updating `opensmtpd`, it requires manual work to go
check in `nixos/tests` whether there is actually a test, especially
given not so many packages in `nixpkgs` have tests and this is thus most
of the time useless.
Finally, for the reviewer, it is much easier to check that the “Tested
via one or more NixOS test(s)” has been checked if the file modified
already includes the list of relevant tests.
Implementation
--------------
Currently, this commit only adds the metadata in the package. Each
element of the `meta.tests` attribute is a derivation that, when it
builds successfully, means the test has passed (ie. following the same
convention as NixOS tests).
Future Work
-----------
In the future, the tools could be made aware of this `meta.tests`
attribute, and for instance a `--with-tests` could be added to
`nix-build` so that it also builds all the tests. Or a `--without-tests`
to build without all the tests. @Profpatsch described in his NixCon talk
such systems.
Another thing that would help in the future would be the possibility to
reasonably easily have cross-derivation nix tests without the whole
NixOS VM stack. @7c6f434c already proposed such a system.
This RFC currently handles none of these concerns. Only the addition of
`meta.tests` as metadata to be used by maintainers to remember to run
relevant tests.
The `unfree` and `unfreeRedistributable` licenses both have `free = false`,
which will trigger the first portion of logic. This removes dead code to
simplify the logic.
As a follow-up, I plan to add an attribute `redistributable = [true|false]`,
which can be used by Hydra to determine whether a given package with a given
license can be included in the channel.
If meta.outputsToInstall is set to include absent outputs, various
tools break including channel updates and nix-env.
grahamc@Morbo> nix-env -i -f . -A elf-header-real
installing 'elf-header'
error: this derivation has bad 'meta.outputsToInstall'
This patch verifies each value in meta.outputsToInstall is a valid
output. It validates this condition only if checkMeta is true.
grahamc@Morbo> nix-build . -A elf-header-real
error: Package ‘elf-header’ in /home/grahamc/projects/nixpkgs/pkgs/development/libraries/elf-header/default.nix:36 has invalid meta.outputsToInstall, refusing to evaluate.
The package elf-header has set meta.outputsToInstall to: bin
however elf-header only has the outputs: out
and is missing the following ouputs:
- bin
(use '--show-trace' to show detailed location information)
Note, now the nix-env experience is decidedly worse for users who have
checkMeta set to true:
grahamc@Morbo> nix-env -i -f . -A elf-header-real; echo $?
0
though since this is already an issue for unfree, broken, unsupported,
and insecure validity problems I'm not sure we should do something
different here.
- `localSystem` is added, it strictly supercedes system
- `crossSystem`'s description mentions `localSystem` (and vice versa).
- No more weird special casing I don't even understand
TEMP
First, we need check against the host platform, not the build platform.
That's simple enough.
Second, we move away from exahustive finite case analysis (i.e.
exhaustively listing all platforms the package builds on). That only
work in a closed-world setting, where we know all platforms we might
build one. But with cross compilation, we may be building for arbitrary
platforms, So we need fancier filters. This is the closed world to open
world change.
The solution is instead of having a list of systems (strings in the form
"foo-bar"), we have a list of of systems or "patterns", i.e. attributes
that partially match the output of the parsers in `lib.systems.parse`.
The "check meta" logic treats the systems strings as an exact whitelist
just as before, but treats the patterns as a fuzzy whitelist,
intersecting the actual `hostPlatform` with the pattern and then
checking for equality. (This is done using `matchAttrs`).
The default convenience lists for `meta.platforms` are now changed to be
lists of patterns (usually a single pattern) in
`lib/systems/for-meta.nix` for maximum flexibility under this new
system.
Fixes#30902
This pushes check-meta evaluation to derivation evaluation step, leaving all other
attributes accessible.
Before this commit:
> $ HOME=/homeless-shelter NIX_PATH=nixpkgs=$(pwd) nix-instantiate --eval --strict ./default.nix -A xen --argstr system aarch64-linux
> Package ‘xen-4.5.5’ in pkgs/applications/virtualization/xen/generic.nix:226 is not supported on ‘aarch64-linux’, refusing to evaluate.
as expected
> $ HOME=/homeless-shelter NIX_PATH=nixpkgs=$(pwd) nix-instantiate --eval --strict ./default.nix -A xen.name --argstr system aarch64-linux
> Package ‘xen-4.5.5’ in pkgs/applications/virtualization/xen/generic.nix:226 is not supported on ‘aarch64-linux’, refusing to evaluate.
> $ HOME=/homeless-shelter NIX_PATH=nixpkgs=$(pwd) nix-instantiate --eval --strict ./default.nix -A xen.meta.description --argstr system aarch64-linux
> Package ‘xen-4.5.5’ in pkgs/applications/virtualization/xen/generic.nix:226 is not supported on ‘aarch64-linux’, refusing to evaluate.
which is unfortunate since its impossible to use packages in autogenerated
documentation on all platforms.
After this commit:
> $ HOME=/homeless-shelter NIX_PATH=nixpkgs=$(pwd) nix-instantiate --eval --strict ./default.nix -A xen --argstr system aarch64-linux
still fails
> $ HOME=/homeless-shelter NIX_PATH=nixpkgs=$(pwd) nix-instantiate --eval --strict ./default.nix -A xen.name --argstr system aarch64-linux
> "xen-4.5.5"
> $ HOME=/homeless-shelter NIX_PATH=nixpkgs=$(pwd) nix-instantiate --eval --strict ./default.nix -A xen.meta.description --argstr system aarch64-linux
> "Xen hypervisor and related components (vanilla)"
- tracing seems annoying enough
- we get errors for all packages instead of aborting on the first one
- easier to differentiate from unwanted packages (broken, unfree, etc.)
