Fix crash when importing .tres files that are not palettes

Translations/Translations.pot

@@ -307,10 +307,17 @@ msgstr ""
 msgid "Exporting in progress..."
 msgstr ""
 
+msgid "Can't load file '%s'."
+msgstr ""
+
 msgid "Can't load file '%s'.\n"
 "Error code: %s"
 msgstr ""
 
+msgid "Can't load file '%s'.\n"
+"This is not a valid palette file."
+msgstr ""
+
 msgid "Frame"
 msgstr ""
 

src/Autoload/OpenSave.gd

@@ -23,8 +23,20 @@ func handle_loading_files(files: PoolStringArray) -> void:
 		var file_ext: String = file.get_extension().to_lower()
 		if file_ext == "pxo":  # Pixelorama project file
 			open_pxo_file(file)
-		elif file_ext == "tres" or file_ext == "gpl" or file_ext == "pal" or file_ext == "json":
+
-			Palettes.import_palette(file)
+		elif file_ext == "tres":  # Godot resource file
+			var resource = load(file)
+			if resource is Palette:
+				Palettes.import_palette(resource, file.get_file())
+			else:
+				var file_name: String = file.get_file()
+				Global.error_dialog.set_text(tr("Can't load file '%s'.") % [file_name])
+				Global.error_dialog.popup_centered()
+				Global.dialog_open(true)
+
+		elif file_ext == "gpl" or file_ext == "pal" or file_ext == "json":
+			Palettes.import_palette_from_path(file)
+
 		else:  # Image files
 			var image := Image.new()
 			var err := image.load(file)

src/Autoload/Palettes.gd

@@ -1,3 +1,4 @@
+# gdlint: ignore=max-public-methods
 extends Node
 
 # Presets for creating a new palette
@@ -428,15 +429,13 @@ func _get_best_palette_file_location(looking_paths: Array, fname: String):  # ->
 	return null
 
 
-func import_palette(path: String) -> void:
+func import_palette_from_path(path: String) -> void:
 	if does_palette_exist(path.get_basename().get_file()):
 		# If there is a palette with same name ignore import for now
 		return
 
 	var palette: Palette = null
 	match path.to_lower().get_extension():
-		"tres":
-			palette = load(path)
 		"gpl":
 			var file = File.new()
 			if file.file_exists(path):
@@ -464,12 +463,25 @@ func import_palette(path: String) -> void:
 				file.close()
 				palette = _import_json_palette(text)
 
+	import_palette(palette, path.get_file())
+
+
+func import_palette(palette: Palette, file_name: String) -> void:
+	if does_palette_exist(file_name.get_basename()):
+		# If there is a palette with same name ignore import for now
+		return
 	if palette:
 		var palette_path := _save_palette(palette)
 		palettes[palette_path] = palette
 		select_palette(palette_path)
 		Global.palette_panel.setup_palettes_selector()
 		Global.palette_panel.select_palette(palette_path)
+	else:
+		Global.error_dialog.set_text(
+			tr("Can't load file '%s'.\nThis is not a valid palette file.") % [file_name]
+		)
+		Global.error_dialog.popup_centered()
+		Global.dialog_open(true)
 
 
 func _import_gpl(path: String, text: String) -> Palette:

src/UI/Dialogs/PreviewDialog.gd

@@ -114,7 +114,7 @@ func _on_PreviewDialog_confirmed() -> void:
 		OpenSave.open_image_as_new_layer(image, path.get_basename().get_file(), frame_index)
 
 	elif current_import_option == ImageImportOptions.PALETTE:
-		Palettes.import_palette(path)
+		Palettes.import_palette_from_path(path)
 
 	elif current_import_option == ImageImportOptions.BRUSH:
 		add_brush()