nautilus-python not loading python-extension

[Stunkymonkey]

Describe the bug
nautilus-python does not load python-extension of nautilus to display a context menu entry.

To Reproduce
Steps to reproduce the behavior:

1. install gnomeExtensions.nautilus-open-any-terminal from Stunkymonkey@da1610b
2. restart nautilus
3. no context menu is shown

Expected behavior
a new context menu entry, that could open e.g. alacritty

Additional context
Maybe I am doing something wrong. I am pretty new to nix. Maybe you could help

Notify maintainers
i guess @hedning, @dasj19, @maxeaubrey

Metadata

 - system: `"x86_64-linux"`
 - host os: `Linux 5.12.4, NixOS, 21.05.804.5de44c15758 (Okapi)`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.3.12`
 - channels(user): `""`
 - channels(root): `"nixos-21.05.804.5de44c15758, nixos-unstable-21.05pre277486.f5e8bdd07d1"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

Maintainer information:

# a list of nixos modules affected by the problem
module: gnomeExtensions.nautilus-open-any-terminal

[dasj19]

Idk how much help this is but have you tried looking at how nautilus-python is defined: https://github.com/NixOS/nixpkgs/blob/master/pkgs/desktops/gnome/misc/nautilus-python/default.nix

I think that the following line specifically says that only extensions in $out/lib/nautilus/extensions-3.0 are loaded.
PKG_CONFIG_LIBNAUTILUS_EXTENSION_EXTENSIONDIR = "${placeholder "out"}/lib/nautilus/extensions-3.0";

[Stunkymonkey]

tried it, but does not work.
additionally i found mat2 which tries to do the same thing. unfortunately it does not work as well.

[jtojnar]

nautilus-python did not work properly before #142824.

---

We rely on GNOME NixOS module setting NAUTILUS_EXTENSION_DIR environment variable for Nautilus to be find nautilus-python. That means nautilus-python needs to be installed via environment.systemPackages.

nautilus-python then needs its extensions to be available on XDG_DATA_DIRS path (in nautilus-python/extensions subdirectory). And it might fail if the extension depends on anything other than Nautilus and its dependencies.

[Stunkymonkey]

thanks for the expanation 👍 .
can you confirm, that mat2 is working? (right-clicking on jpegs, mp3s, ... should have an extra entry about removing metadata)
I have gnome.nautilus-python installed system-wide. But still do not see the context-menu.

If you have a second please look over my last commit: https://github.com/Stunkymonkey/nixpkgs/tree/nautilus-open-any-terminal

[jtojnar]

Running nautilus in the console shows the following with mat2 installed:

Traceback (most recent call last):
  File "/home/jtojnar/.nix-profile/share/nautilus-python/extensions/mat2.py", line 28, in <module>
    from libmat2 import parser_factory
  File "/nix/store/x7rfd5lxym1zx7m15yhk0i6hlbfr4cwd-python3.9-mat2-0.12.3/lib/python3.9/site-packages/libmat2/parser_factory.py", line 30, in <module>
    __load_all_parsers()
  File "/nix/store/x7rfd5lxym1zx7m15yhk0i6hlbfr4cwd-python3.9-mat2-0.12.3/lib/python3.9/site-packages/libmat2/parser_factory.py", line 27, in __load_all_parsers
    importlib.import_module('.' + name, package='libmat2')
  File "/nix/store/gras7a25yy9f7djmzrgh1bsiiacg0s9c-python3-3.9.9/lib/python3.9/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/nix/store/x7rfd5lxym1zx7m15yhk0i6hlbfr4cwd-python3.9-mat2-0.12.3/lib/python3.9/site-packages/libmat2/images.py", line 6, in <module>
    import cairo
ModuleNotFoundError: No module named 'cairo'

so that is an issue with extra dependencies (python3.pkgs.pycairo). I guess the best solution would be manipulating python path in mat2 like python wrappers do.

[Stunkymonkey]

my first goal will be to get the same error for mat2 as you do. Because i never managed to get nautilus-python source any files.

i have nautilus-python and mat2 both installed.

Do I have to set NAUTILUS_EXTENSION_DIR like this?

NAUTILUS_EXTENSION_DIR=$(nix-store --query --requisites /run/current-system | grep "nautilus-python-1.2.3$")/lib/nautilus/extensions-3.0 nautilus

or is like this?

XDG_DATA_DIRS=$(nix-store --query --requisites /run/current-system | grep "mat2")/share/nautilus-python/extensions:$XDG_DATA_DIRS nautilus

sorry I am a bit lost here 🙈

[jtojnar]

NAUTILUS_EXTENSION_DIR can only contain a single directory. And that should be /run/current-system/sw/lib/nautilus/extensions-3.0, where all the Nautilus extensions are symlinked thanks to environment.systemPackages:

nixpkgs/nixos/modules/services/x11/desktop-managers/gnome.nix

Line 556 in bc97152

environment.sessionVariables.NAUTILUS_EXTENSION_DIR = "${config.system.path}/lib/nautilus/extensions-3.0";

XDG_DATA_DIRS should contain /run/current-system/sw/share on NixOS by default (note that it only contains the share/ directory. If you do not use GNOME, you might also need environment.pathsToLink so that environment.systemPackages creates a symlink.

But yeah, something like the following should work:

env "NAUTILUS_EXTENSION_DIR=$(nix-build -A gnome.nautilus-python --no-out-link)/lib/nautilus/extensions-3.0" "XDG_DATA_DIRS=$(nix-build -A mat2 --no-out-link)/share:$XDG_DATA_DIRS" nautilus

[Stunkymonkey]

If you do not use GNOME, you might also need environment.pathsToLink so that environment.systemPackages creates a symlink.

this was exactly my problem. by adding this the extensions will get loaded. Thanks for your help.