Trade: why am I returning naked pointer from a function?!

src/Magnum/Trade/AbstractImageConverter.cpp

@@ -29,22 +29,24 @@
 #include <Corrade/Utility/Assert.h>
 #include <Corrade/Utility/Directory.h>
 
+#include "Magnum/Image.h"
+
 namespace Magnum { namespace Trade {
 
 AbstractImageConverter::AbstractImageConverter() = default;
 
 AbstractImageConverter::AbstractImageConverter(PluginManager::AbstractManager& manager, std::string plugin): AbstractPlugin(manager, std::move(plugin)) {}
 
-Image2D* AbstractImageConverter::exportToImage(const ImageReference2D& image) const {
+std::optional<Image2D> AbstractImageConverter::exportToImage(const ImageReference2D& image) const {
     CORRADE_ASSERT(features() & Feature::ConvertImage,
-        "Trade::AbstractImageConverter::exportToImage(): feature not supported", nullptr);
+        "Trade::AbstractImageConverter::exportToImage(): feature not supported", {});
 
     return doExportToImage(image);
 }
 
-Image2D* AbstractImageConverter::doExportToImage(const ImageReference2D&) const {
-    CORRADE_ASSERT(false, "Trade::AbstractImageConverter::exportToImage(): feature advertised but not implemented", nullptr);
-    return nullptr;
+std::optional<Image2D> AbstractImageConverter::doExportToImage(const ImageReference2D&) const {
+    CORRADE_ASSERT(false, "Trade::AbstractImageConverter::exportToImage(): feature advertised but not implemented", {});
+    return std::nullopt;
 }
 
 Containers::Array<char> AbstractImageConverter::exportToData(const ImageReference2D& image) const {

src/Magnum/Trade/AbstractImageConverter.h

@@ -34,6 +34,7 @@
 #include "Magnum/Magnum.h"
 #include "Magnum/visibility.h"
 #include "Magnum/Text/Text.h"
+#include "MagnumExternal/Optional/optional.hpp"
 
 namespace Magnum { namespace Trade {
 
@@ -95,10 +96,10 @@ class MAGNUM_EXPORT AbstractImageConverter: public PluginManager::AbstractPlugin
          * @brief Convert image to different format
          *
          * Available only if @ref Feature::ConvertImage is supported. Returns
-         * converted image on success, `nullptr` otherwise.
+         * converted image on success, `std::nullopt` otherwise.
          * @see @ref features(), @ref exportToData(), @ref exportToFile()
          */
-        Image2D* exportToImage(const ImageReference2D& image) const;
+        std::optional<Image2D> exportToImage(const ImageReference2D& image) const;
 
         /**
          * @brief Export image to raw data
@@ -126,7 +127,7 @@ class MAGNUM_EXPORT AbstractImageConverter: public PluginManager::AbstractPlugin
         virtual Features doFeatures() const = 0;
 
         /** @brief Implementation of @ref exportToImage() */
-        virtual Image2D* doExportToImage(const ImageReference2D& image) const;
+        virtual std::optional<Image2D> doExportToImage(const ImageReference2D& image) const;
 
         /** @brief Implementation of @ref exportToData() */
         virtual Containers::Array<char> doExportToData(const ImageReference2D& image) const;