ensure we dispose beffers when decoders throw

src/Directory.Build.props

@@ -27,6 +27,7 @@
     <InternalsVisibleTo Include="ImageSharp.Benchmarks" Key="$(SixLaborsPublicKey)" />
     <InternalsVisibleTo Include="ImageSharp.Tests.ProfilingSandbox" Key="$(SixLaborsPublicKey)" />
     <InternalsVisibleTo Include="SixLabors.ImageSharp.Tests" Key="$(SixLaborsPublicKey)" />
+    <InternalsVisibleTo Include="SixLabors.ImageSharp.Drawing.Tests" Key="$(SixLaborsPublicKey)" />
   </ItemGroup>
 
 </Project>

src/ImageSharp/Formats/Jpeg/Components/Decoder/SpectralConverter{TPixel}.cs

@@ -95,7 +95,9 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
                 }
             }
 
-            return this.pixelBuffer;
+            var buffer = this.pixelBuffer;
+            this.pixelBuffer = null;
+            return buffer;
         }
 
         /// <inheritdoc/>
@@ -210,6 +212,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
 
             this.rgbBuffer?.Dispose();
             this.paddedProxyPixelRow?.Dispose();
+            this.pixelBuffer?.Dispose();
         }
     }
 }

src/ImageSharp/Formats/Jpeg/JpegDecoderCore.cs

@@ -187,20 +187,27 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
             where TPixel : unmanaged, IPixel<TPixel>
         {
             using var spectralConverter = new SpectralConverter<TPixel>(this.Configuration);
-
-            var scanDecoder = new HuffmanScanDecoder(stream, spectralConverter, cancellationToken);
-
-            this.ParseStream(stream, scanDecoder, cancellationToken);
-            this.InitExifProfile();
-            this.InitIccProfile();
-            this.InitIptcProfile();
-            this.InitXmpProfile();
-            this.InitDerivedMetadataProperties();
-
-            return new Image<TPixel>(
-                this.Configuration,
-                spectralConverter.GetPixelBuffer(cancellationToken),
-                this.Metadata);
+            try
+            {
+                var scanDecoder = new HuffmanScanDecoder(stream, spectralConverter, cancellationToken);
+
+                this.ParseStream(stream, scanDecoder, cancellationToken);
+                this.InitExifProfile();
+                this.InitIccProfile();
+                this.InitIptcProfile();
+                this.InitXmpProfile();
+                this.InitDerivedMetadataProperties();
+
+                return new Image<TPixel>(
+                    this.Configuration,
+                    spectralConverter.GetPixelBuffer(cancellationToken),
+                    this.Metadata);
+            }
+            catch
+            {
+                this.Frame?.Dispose();
+                throw;
+            }
         }
 
         /// <inheritdoc/>

src/ImageSharp/Formats/Tiff/TiffDecoderCore.cs

@@ -157,40 +157,52 @@ namespace SixLabors.ImageSharp.Formats.Tiff
         public Image<TPixel> Decode<TPixel>(BufferedReadStream stream, CancellationToken cancellationToken)
             where TPixel : unmanaged, IPixel<TPixel>
         {
-            this.inputStream = stream;
-            var reader = new DirectoryReader(stream, this.Configuration.MemoryAllocator);
-
-            IEnumerable<ExifProfile> directories = reader.Read();
-            this.byteOrder = reader.ByteOrder;
-            this.isBigTiff = reader.IsBigTiff;
-
             var frames = new List<ImageFrame<TPixel>>();
-            foreach (ExifProfile ifd in directories)
+            try
             {
-                cancellationToken.ThrowIfCancellationRequested();
-                ImageFrame<TPixel> frame = this.DecodeFrame<TPixel>(ifd, cancellationToken);
-                frames.Add(frame);
+                this.inputStream = stream;
+                var reader = new DirectoryReader(stream, this.Configuration.MemoryAllocator);
+
+                IEnumerable<ExifProfile> directories = reader.Read();
+                this.byteOrder = reader.ByteOrder;
+                this.isBigTiff = reader.IsBigTiff;
 
-                if (this.decodingMode is FrameDecodingMode.First)
+                foreach (ExifProfile ifd in directories)
                 {
-                    break;
+                    cancellationToken.ThrowIfCancellationRequested();
+                    ImageFrame<TPixel> frame = this.DecodeFrame<TPixel>(ifd, cancellationToken);
+                    frames.Add(frame);
+
+                    if (this.decodingMode is FrameDecodingMode.First)
+                    {
+                        break;
+                    }
                 }
-            }
 
-            ImageMetadata metadata = TiffDecoderMetadataCreator.Create(frames, this.ignoreMetadata, reader.ByteOrder, reader.IsBigTiff);
+                ImageMetadata metadata = TiffDecoderMetadataCreator.Create(frames, this.ignoreMetadata, reader.ByteOrder, reader.IsBigTiff);
 
-            // TODO: Tiff frames can have different sizes.
-            ImageFrame<TPixel> root = frames[0];
-            this.Dimensions = root.Size();
-            foreach (ImageFrame<TPixel> frame in frames)
-            {
-                if (frame.Size() != root.Size())
+                // TODO: Tiff frames can have different sizes.
+                ImageFrame<TPixel> root = frames[0];
+                this.Dimensions = root.Size();
+                foreach (ImageFrame<TPixel> frame in frames)
                 {
-                    TiffThrowHelper.ThrowNotSupported("Images with different sizes are not supported");
+                    if (frame.Size() != root.Size())
+                    {
+                        TiffThrowHelper.ThrowNotSupported("Images with different sizes are not supported");
+                    }
                 }
+
+                return new Image<TPixel>(this.Configuration, metadata, frames);
             }
+            catch
+            {
+                foreach (ImageFrame<TPixel> f in frames)
+                {
+                    f.Dispose();
+                }
 
-            return new Image<TPixel>(this.Configuration, metadata, frames);
+                throw;
+            }
         }
 
         /// <inheritdoc/>