Python "no return values, shouldn't happen"

[Nathan]

I'm creating a python script to load a custom image format (.PRS with the magic string "YB").  But I'm having trouble getting even a skeleton file loading plugin to work.  This is what I've been able to reduce my code down to:

Code:

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import gi
gi.require_version('Gimp', '3.0')
from gi.repository import Gimp, GObject
import sys

load_proc = "file-prs-load"
plugin_binary = "file-prs"

class PrsLoader(Gimp.PlugIn):
   def do_query_procedures(self):
       return [load_proc]
   
   def do_create_procedure(self, name):
       procedure = None
       
       if name == load_proc:
           procedure = Gimp.LoadProcedure.new(self, name,
                                               Gimp.PDBProcType.PLUGIN,
                                               self.PrsLoad, None)
           procedure.set_menu_label("PRS image")
           procedure.set_attribution("Nathan", "Nathan", "2025")
           procedure.set_menu_label("PRS image")
           procedure.set_documentation("Loads files of PRS file format",
                                       "Loads files of PRS file format",
                                       None)
           procedure.set_mime_types("image/prs")
           procedure.set_extensions("prs")
           procedure.set_magics("0,string,YB")
       return procedure
   
   def PrsLoad(self, procedure, run_mode, file, metadata, flags, config, run_data):
       print("PrsLoad called")

       #Return dummy image for now
       image = Gimp.Image.new(100, 100, Gimp.ImageBaseType.RGB)

       return_vals = procedure.new_return_values(Gimp.PDBStatusType.SUCCESS, None)
       val = GObject.Value(Gimp.Image.__gtype__, image)
       return_vals.append(val)

       return return_vals

Gimp.main(PrsLoader.__gtype__, sys.argv)

When I try to open a PRS image file, I get the following errors:

Code:

GIMP Message
Opening '/home/nathan/Pictures/tree2b.prs' failed:
PRS image plug-in could not open image

Code:

[nathan@TARDIS file-prs]$ gimp
set device 'Wayland Pointer' to mode: disabled
[file-prs-load] The catalog directory does not exist: /home/nathan/.config/GIMP/3.0/plug-ins/file-prs/locale
[file-prs-load] Override method set_i18n() for the plug-in to customize or disable localization.
[file-prs-load] Localization disabled
env: ‘gjs’: No such file or directory
gimp: LibGimpBase-WARNING: gimp: gimp_wire_read(): unexpected EOF
[file-prs-load] The catalog directory does not exist: /home/nathan/.config/GIMP/3.0/plug-ins/file-prs/locale
[file-prs-load] Override method set_i18n() for the plug-in to customize or disable localization.
[file-prs-load] Localization disabled
[file-prs-load] The catalog directory does not exist: /home/nathan/.config/GIMP/3.0/plug-ins/file-prs/locale
[file-prs-load] Override method set_i18n() for the plug-in to customize or disable localization.
[file-prs-load] Localization disabled
PrsLoad called

(file-prs.py:2595385): LibGimp-WARNING **: 17:46:44.730: _gimp_procedure_run_array: no return values, shouldn't happen
/home/nathan/.config/GIMP/3.0/plug-ins/file-prs/file-prs.py:46: Warning: g_error_new: assertion 'domain != 0' failed
 Gimp.main(PrsLoader.__gtype__, sys.argv)
INFO: a stray image seems to have been left around by a plug-in: "[Untitled]"[nathan@TARDIS file-prs]$

I'm not too worried about the localization messages at this time.

[Ofnuts]

Yes, the locale message can be ignored.

Looking at the message I would wonder what makes it try to invoke that gjs command (somewhere in another script?). Is it because the path/libpath that are expected aren't the ones that are used under Gimp? Or if you are using a flatpak or snap Gimp installation their virtual filesystem doesn't include the one where the gjs command resides (or map it to their own local file system)?

[Nathan]

(4 hours ago)Ofnuts Wrote: Yes, the locale message can be ignored.

Looking at the message I would wonder what makes it try to invoke that gjs command (somewhere in another script?). Is it because the path/libpath that are expected aren't the ones that are used under Gimp? Or if you are using a flatpak or snap Gimp installation their virtual filesystem doesn't include the one where the gjs command resides (or map it to their own local file system)?

I'm using arch linux and it's installed via the pacman package manager.  I installed the gjs package (JavaScript Bindings for GNOME), and it clears up that error message, but I still have the same problem.

Code:

[nathan@TARDIS file-prs]$ gimp
set device 'Wayland Pointer' to mode: disabled
[file-prs-load] The catalog directory does not exist: /home/nathan/.config/GIMP/3.0/plug-ins/file-prs/locale
[file-prs-load] Override method set_i18n() for the plug-in to customize or disable localization.
[file-prs-load] Localization disabled
[file-prs-load] The catalog directory does not exist: /home/nathan/.config/GIMP/3.0/plug-ins/file-prs/locale
[file-prs-load] Override method set_i18n() for the plug-in to customize or disable localization.
[file-prs-load] Localization disabled
PrsLoad called

(file-prs.py:3219474): LibGimp-WARNING **: 03:52:04.070: _gimp_procedure_run_array: no return values, shouldn't happen
/home/nathan/.config/GIMP/3.0/plug-ins/file-prs/file-prs.py:46: Warning: g_error_new: assertion 'domain != 0' failed
 Gimp.main(PrsLoader.__gtype__, sys.argv)
INFO: a stray image seems to have been left around by a plug-in: "[Untitled]"[nathan@TARDIS file-prs]$