Adapted to Corrade::PluginManager changes.

doc/plugins.dox

@@ -120,10 +120,6 @@ lifetime of all plugin instances created from it.
         std::exit(1);
     }
     std::unique_ptr<Trade::AbstractImporter> tgaImporter = manager.instance("TgaImporter");
-    if(!tgaImporter) {
-        Error() << "Cannot instantiate TgaImporter plugin";
-        std::exit(2);
-    }
 
     // Use the plugin...
 

src/Magnum/Text/fontconverter.cpp

@@ -72,21 +72,15 @@ int FontConverter::exec() {
 
     /* Load font */
     PluginManager::Manager<Text::AbstractFont> fontManager(Utility::Directory::join(MAGNUM_PLUGINS_DIR, "fonts/"));
-    std::unique_ptr<Text::AbstractFont> font;
+    if(!(fontManager.load(args.value("font")) & PluginManager::LoadState::Loaded))
-    if(!(fontManager.load(args.value("font")) & PluginManager::LoadState::Loaded) ||
-       !(font = fontManager.instance(args.value("font")))) {
-        Error() << "Cannot load plugin" << args.value("font") << "from" << fontManager.pluginDirectory();
         std::exit(1);
-    }
+    std::unique_ptr<Text::AbstractFont> font = fontManager.instance(args.value("font"));
 
     /* Load font converter */
     PluginManager::Manager<Text::AbstractFontConverter> converterManager(Utility::Directory::join(MAGNUM_PLUGINS_DIR, "fontconverters/"));
-    std::unique_ptr<Text::AbstractFontConverter> converter;
+    if(!(converterManager.load(args.value("converter")) & PluginManager::LoadState::Loaded))
-    if(!(converterManager.load(args.value("converter")) & PluginManager::LoadState::Loaded) ||
-       !(converter = converterManager.instance(args.value("converter")))) {
-        Error() << "Cannot load plugin" << args.value("converter") << "from" << converterManager.pluginDirectory();
         std::exit(1);
-    }
+    std::unique_ptr<Text::AbstractFontConverter> converter = converterManager.instance(args.value("converter"));
 
     /* Open font */
     if(!font->openFile(args.value("input"), args.value<Float>("font-size"))) {

src/Magnum/TextureTools/distancefieldconverter.cpp

@@ -66,23 +66,17 @@ DistanceFieldConverter::DistanceFieldConverter(const Arguments& arguments): Wind
 }
 
 int DistanceFieldConverter::exec() {
-    /* Load plugins */
+    /* Load importer plugin */
     PluginManager::Manager<Trade::AbstractImporter> importerManager(MAGNUM_IMPORTER_PLUGIN_DIR);
-    if(!(importerManager.load(args.value("importer")) & PluginManager::LoadState::Loaded)) {
+    if(!(importerManager.load(args.value("importer")) & PluginManager::LoadState::Loaded))
-        Error() << "Cannot load importer plugin" << args.value("importer") << "from" << MAGNUM_IMPORTER_PLUGIN_DIR;
         return 1;
-    }
+    std::unique_ptr<Trade::AbstractImporter> importer = importerManager.instance(args.value("importer"));
+
+    /* Load converter plugin */
     PluginManager::Manager<Trade::AbstractImageConverter> converterManager(MAGNUM_IMAGECONVERTER_PLUGIN_DIR);
-    if(!(converterManager.load(args.value("converter")) & PluginManager::LoadState::Loaded)) {
+    if(!(converterManager.load(args.value("converter")) & PluginManager::LoadState::Loaded))
-        Error() << "Cannot load converter plugin" << args.value("converter") << "from" << MAGNUM_IMAGECONVERTER_PLUGIN_DIR;
         return 1;
-    }
-
-    /* Instance plugins */
-    std::unique_ptr<Trade::AbstractImporter> importer = importerManager.instance(args.value("importer"));
-    CORRADE_INTERNAL_ASSERT(importer);
     std::unique_ptr<Trade::AbstractImageConverter> converter = converterManager.instance(args.value("converter"));
-    CORRADE_INTERNAL_ASSERT(converter);
 
     /* Open input file */
     std::optional<Trade::ImageData2D> image;