Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
6.1 KiB
Hacking
This section provides some notes on how to hack on Nix. To get the latest version of Nix from GitHub:
$ git clone https://github.com/NixOS/nix.git
$ cd nix
To build Nix for the current operating system/architecture use
$ nix-build
or if you have a flake-enabled nix:
$ nix build
This will build defaultPackage
attribute defined in the flake.nix
file. To build for other platforms add one of the following suffixes to
it: aarch64-linux, i686-linux, x86_64-darwin, x86_64-linux. i.e.
$ nix-build -A defaultPackage.x86_64-linux
To build all dependencies and start a shell in which all environment variables are set up so that those dependencies can be found:
$ nix-shell
or if you have a flake-enabled nix:
$ nix develop
To get a shell with a different compilation environment (e.g. stdenv, gccStdenv, clangStdenv, clang11Stdenv):
$ nix-shell -A devShells.x86_64-linux.clang11StdenvPackages
or if you have a flake-enabled nix:
$ nix develop .#clang11StdenvPackages
To build Nix itself in this shell:
[nix-shell]$ ./bootstrap.sh
[nix-shell]$ ./configure $configureFlags --prefix=$(pwd)/outputs/out
[nix-shell]$ make -j $NIX_BUILD_CORES
To install it in $(pwd)/outputs
and test it:
[nix-shell]$ make install
[nix-shell]$ make installcheck -j $NIX_BUILD_CORES
[nix-shell]$ ./outputs/out/bin/nix --version
nix (Nix) 3.0
If you have a flakes-enabled Nix you can replace:
$ nix-shell
by:
$ nix develop
Running tests
Unit-tests
The unit-tests for each Nix library (libexpr
, libstore
, etc..) are defined
under src/{library_name}/tests
using the
googletest framework.
You can run the whole testsuite with make check
, or the tests for a specific component with make libfoo-tests_RUN
. Finer-grained filtering is also possible using the --gtest_filter command-line option.
Functional tests
The functional tests reside under the tests
directory and are listed in tests/local.mk
.
The whole testsuite can be run with make install && make installcheck
.
Individual tests can be run with make tests/{testName}.sh.test
.
Integration tests
The integration tests are defined in the Nix flake under the hydraJobs.tests
attribute.
These tests include everything that needs to interact with external services or run Nix in a non-trivial distributed setup.
Because these tests are expensive and require more than what the standard github-actions setup provides, they only run on the master branch (on https://hydra.nixos.org/jobset/nix/master).
You can run them manually with nix build .#hydraJobs.tests.{testName}
or nix-build -A hydraJobs.tests.{testName}
Installer tests
After a one-time setup, the Nix repository's GitHub Actions continuous integration (CI) workflow can test the installer each time you push to a branch.
Creating a Cachix cache for your installer tests and adding its authorization token to GitHub enables two installer-specific jobs in the CI workflow:
-
The
installer
job generates installers for the platforms below and uploads them to your Cachix cache:x86_64-linux
armv6l-linux
armv7l-linux
x86_64-darwin
-
The
installer_test
job (which runs onubuntu-latest
andmacos-latest
) will try to install Nix with the cached installer and run a trivial Nix command.
One-time setup
- Have a GitHub account with a fork of the Nix repository.
- At cachix.org:
- Create or log in to an account.
- Create a Cachix cache using the format
<github-username>-nix-install-tests
. - Navigate to the new cache > Settings > Auth Tokens.
- Generate a new Cachix auth token and copy the generated value.
- At github.com:
- Navigate to your Nix fork > Settings > Secrets > Actions > New repository secret.
- Name the secret
CACHIX_AUTH_TOKEN
. - Paste the copied value of the Cachix cache auth token.
Using the CI-generated installer for manual testing
After the CI run completes, you can check the output to extract the installer URL:
-
Click into the detailed view of the CI run.
-
Click into any
installer_test
run (the URL you're here to extract will be the same in all of them). -
Click into the
Run cachix/install-nix-action@v...
step and click the detail triangle next to the first log line (it will also beRun cachix/install-nix-action@v...
) -
Copy the value of
install_url
-
To generate an install command, plug this
install_url
and your GitHub username into this template:sh <(curl -L <install_url>) --tarball-url-prefix https://<github-username>-nix-install-tests.cachix.org/serve