Qtile NixOS build fix for failing test suite

I was updating my NixOS machine, and right at the end, the rebuild failed. Some packages have been problematic for me in the past, such as oh-my-pi, but when I checked the logs it was not one of the usual suspects. Suprisingly, the failure was coming from qtile (the Python-based tiling window manager).

The logs included the following lines:

       > -- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
       > =========================== short test summary info ============================
       > FAILED test/test_manager.py::test_reload_config[1-x11] - AssertionError: assert 'dd' in []
       > FAILED test/shell_scripts/test_repl_server.py::test_repl_server_executes_code - ConnectionResetError: Connection lost
       > ERROR test/test_dgroups.py::test_dgroup_spawn_in_group[1-x11-DGroupsSpawnConfig] - AssertionError: Error launching qtile

What worked in the end for me was to skip the Qtile test suite for this package build. You can do that by adding the following to your configuration.nix:

services.xserver.windowManager.qtile = {
  enable = true;
  package = pkgs.python3.pkgs.qtile.overrideAttrs (_: {
    doCheck = false;
    doInstallCheck = false;
    dontUsePytestCheck = true;
  });
};

Make sure any overlays you use are not overriding or bypassing this package setting. To check that the option is being applied, run:

nix eval --impure --json --expr \
  '(let c = (builtins.getFlake "/etc/nixos").nixosConfigurations.nixos.config; in c.services.xserver.windowManager.qtile.package.doCheck == false)'

The result should be true.

Before rebuilding the whole system, you can test-build Qtile directly:

nix build --impure --no-link \
  --expr '(builtins.getFlake "/etc/nixos").nixosConfigurations.nixos.config.services.xserver.windowManager.qtile.finalPackage'

There is an issue on GitHub tracking the problem: NixOS/nixpkgs#559128. Once the issue is resolved upstream, this workaround can be removed from your configuration.

Why disable the tests? Seems a bit drastic

“Untested code is garbage code.” Disabling tests was not my first choice, so I tried a few narrower workarounds first.

The error log included Connection lost, and my internet connection is not always reliable, so I initially tried rerunning the build. After a couple of attempts, it became clear that this was not just a network issue.

Next, I tried disabling only the failing tests. I was able to to figure out how to do that, but doing so only uncovered more failures. At that point, disabling 100+ tests would have made my configuration messy and seemed to defeat the purpose of keeping the checks enabled.

In the end, disabling the pytest checks altogether was what allowed the package to build successfully. Hopefully this is fixed upstream, either by adjusting the failing tests or by moving to a smaller post-installation test suite.

Extra technical details

The Qtile NixOS module consumes services.xserver.windowManager.qtile.package, not necessarily the package selected by a separate python313Packages overlay. The module also calls .override on that package to add extra packages, so the override must preserve that interface.

Qtile uses buildPythonPackage with pytestCheckHook. In this nixpkgs version, setting only the final doCheck attribute with overrideAttrs leaves Python install checks and the pytest hook active. The package override disables all of those checks while retaining the module-compatible .override method:

# configuration.nix
services.xserver.windowManager.qtile = {
  enable = true;
  package = pkgs.python3.pkgs.qtile.overrideAttrs (_: {
    doCheck = false;
    doInstallCheck = false;
    dontUsePytestCheck = true;
  });
};

doCheck = false is the required setting on the exact package consumed by Qtile.
doInstallCheck = false disables Python’s separate install-check phase.
dontUsePytestCheck = true prevents pytestCheckHook from adding pytestCheckPhase.

Verification

nix eval --impure --json --expr \
  '(let c = (builtins.getFlake "/etc/nixos").nixosConfigurations.nixos.config; in {
    package = c.services.xserver.windowManager.qtile.package.name;
    doCheck = c.services.xserver.windowManager.qtile.package.doCheck;
    doInstallCheck = c.services.xserver.windowManager.qtile.package.doInstallCheck;
    dontUsePytestCheck = c.services.xserver.windowManager.qtile.package.dontUsePytestCheck;
  })'

The expected values are python3.13-qtile-0.36.0, false, false, and true. A build of the service’s finalPackage should complete successfully without a pytestCheckPhase in the build log.

Original failure log

       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/7lfmh6jjxd36wvv31cdyii61m7jizp69-python3.13-qtile-0.36.0-dist
         /nix/store/j8frdrqpw6yi839sa8l6f30y4wkcr3ip-python3.13-qtile-0.36.0
       Last 25 log lines:
       > test/layouts/test_screensplit.py: 4 warnings
       > test/layouts/test_slice.py: 8 warnings
       > test/layouts/test_spiral.py: 11 warnings
       > test/widgets/test_systray.py: 3 warnings
       > test/widgets/test_tasklist.py: 13 warnings
       > test/widgets/test_textbox.py: 5 warnings
       > test/widgets/test_vertical_clock.py: 8 warnings
       > test/widgets/test_widget_init_configure.py: 13 warnings
       >   /nix/store/h3l4z7p6wny3phbckwwhy1i2g52pdnj4-python3-3.13.15/lib/python3.13/multiprocessing/popen_fork.py:73: DeprecationWarning: This process (pid=1141) is multi-threaded, use of fork() may lead to deadlocks in the child.
       >     self.pid = os.fork()
       >
       > test/layouts/test_common.py: 29 warnings
       > test/layouts/test_floating.py: 2 warnings
       > test/layouts/test_matrix.py: 6 warnings
       > test/layouts/test_max.py: 6 warnings
       > test/widgets/test_widget_init_configure.py: 36 warnings
       >   /nix/store/h3l4z7p6wny3phbckwwhy1i2g52pdnj4-python3-3.13.15/lib/python3.13/multiprocessing/popen_fork.py:73: DeprecationWarning: This process (pid=1147) is multi-threaded, use of fork() may lead to deadlocks in the child.
       >     self.pid = os.fork()
       >
       > -- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
       > =========================== short test summary info ============================
       > FAILED test/test_manager.py::test_reload_config[1-x11] - AssertionError: assert 'dd' in []
       > FAILED test/shell_scripts/test_repl_server.py::test_repl_server_executes_code - ConnectionResetError: Connection lost
       > ERROR test/test_dgroups.py::test_dgroup_spawn_in_group[1-x11-DGroupsSpawnConfig] - AssertionError: Error launching qtile
       > = 2 failed, 1369 passed, 27 skipped, 891 warnings, 1 error, 10 rerun in 1611.61s (0:26:51) =
       For full logs, run:
         nix log /nix/store/cq8544x0b1350hpwshg5ryhkiiz3dfpi-python3.13-qtile-0.36.0.drv
error: Cannot build '/nix/store/3vxsdpmax595b5k4fbx9jcka6hsn2l32-desktops.drv'.

Why disable the tests? Seems a bit drastic

Extra technical details

Verification

Original failure log

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