Gimp-3.0.exe is definitely not a shortcut, its 6.8MB!
I think it's the executable. Actually there are three of exactly the same size: gimp.exe, gimp-3.exe and gimp-3.0.exe. The one the main start menu shortcut uses is gimp-3.exe, doesn't make any difference though which is used, print() statements do not seem to turn up anywhere visible that I can see.
UPDATE:
Ah, but Gimp.message() turns up in the error console. That's a start.
I now find that what is returned from file = config.get_property("...") when it was created with procedure.add_file_argument() is not a string as I thought, it's a GFile (or something), and file.get_path() doesn't produce the path as it does in the working plugin I'm looking at. Don't know why, but it's a start.
I think it's the executable. Actually there are three of exactly the same size: gimp.exe, gimp-3.exe and gimp-3.0.exe. The one the main start menu shortcut uses is gimp-3.exe, doesn't make any difference though which is used, print() statements do not seem to turn up anywhere visible that I can see.
UPDATE:
Ah, but Gimp.message() turns up in the error console. That's a start.
I now find that what is returned from file = config.get_property("...") when it was created with procedure.add_file_argument() is not a string as I thought, it's a GFile (or something), and file.get_path() doesn't produce the path as it does in the working plugin I'm looking at. Don't know why, but it's a start.