Merge pull request #2312 from stefannikolei/stefannikolei/nullable

Remove some nullable disable comments

shared-infrastructure

@@ -1 +1 @@
-Subproject commit bf398a9b6bb6d0acfe0525ee109276b4ef74646c
+Subproject commit 9a82679e92df9476725fd2a2038604fd412af56c

src/ImageSharp/Advanced/AdvancedImageExtensions.cs

@@ -27,8 +27,7 @@ public static class AdvancedImageExtensions
         Guard.NotNull(filePath, nameof(filePath));
 
         string ext = Path.GetExtension(filePath);
-        IImageFormat format = source.GetConfiguration().ImageFormatsManager.FindFormatByFileExtension(ext);
-        if (format is null)
+        if (!source.GetConfiguration().ImageFormatsManager.TryFindFormatByFileExtension(ext, out IImageFormat? format))
         {
             StringBuilder sb = new();
             sb.AppendLine(CultureInfo.InvariantCulture, $"No encoder was found for extension '{ext}'. Registered encoders include:");
@@ -40,7 +39,7 @@ public static class AdvancedImageExtensions
             throw new NotSupportedException(sb.ToString());
         }
 
-        IImageEncoder encoder = source.GetConfiguration().ImageFormatsManager.FindEncoder(format);
+        IImageEncoder? encoder = source.GetConfiguration().ImageFormatsManager.FindEncoder(format);
 
         if (encoder is null)
         {

src/ImageSharp/Formats/Bmp/BmpImageFormatDetector.cs

@@ -1,8 +1,8 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Buffers.Binary;
+using System.Diagnostics.CodeAnalysis;
 
 namespace SixLabors.ImageSharp.Formats.Bmp;
 
@@ -15,9 +15,11 @@ public sealed class BmpImageFormatDetector : IImageFormatDetector
     public int HeaderSize => 2;
 
     /// <inheritdoc/>
-    public IImageFormat DetectFormat(ReadOnlySpan<byte> header)
+    public bool TryDetectFormat(ReadOnlySpan<byte> header, [NotNullWhen(true)] out IImageFormat? format)
     {
-        return this.IsSupportedFileFormat(header) ? BmpFormat.Instance : null;
+        format = this.IsSupportedFileFormat(header) ? BmpFormat.Instance : null;
+
+        return format != null;
     }
 
     private bool IsSupportedFileFormat(ReadOnlySpan<byte> header)
@@ -25,7 +27,8 @@ public sealed class BmpImageFormatDetector : IImageFormatDetector
         if (header.Length >= this.HeaderSize)
         {
             short fileTypeMarker = BinaryPrimitives.ReadInt16LittleEndian(header);
-            return fileTypeMarker == BmpConstants.TypeMarkers.Bitmap || fileTypeMarker == BmpConstants.TypeMarkers.BitmapArray;
+            return fileTypeMarker == BmpConstants.TypeMarkers.Bitmap ||
+                   fileTypeMarker == BmpConstants.TypeMarkers.BitmapArray;
         }
 
         return false;

src/ImageSharp/Formats/Gif/GifImageFormatDetector.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
+
+using System.Diagnostics.CodeAnalysis;
 
 namespace SixLabors.ImageSharp.Formats.Gif;
 
@@ -13,9 +14,10 @@ public sealed class GifImageFormatDetector : IImageFormatDetector
     public int HeaderSize => 6;
 
     /// <inheritdoc/>
-    public IImageFormat DetectFormat(ReadOnlySpan<byte> header)
+    public bool TryDetectFormat(ReadOnlySpan<byte> header, [NotNullWhen(true)] out IImageFormat? format)
     {
-        return this.IsSupportedFileFormat(header) ? GifFormat.Instance : null;
+        format = this.IsSupportedFileFormat(header) ? GifFormat.Instance : null;
+        return format != null;
     }
 
     private bool IsSupportedFileFormat(ReadOnlySpan<byte> header)

src/ImageSharp/Formats/IImageFormatDetector.cs

@@ -1,6 +1,8 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Diagnostics.CodeAnalysis;
+
 namespace SixLabors.ImageSharp.Formats;
 
 /// <summary>
@@ -18,6 +20,7 @@ public interface IImageFormatDetector
     /// Detect mimetype
     /// </summary>
     /// <param name="header">The <see cref="T:byte[]"/> containing the file header.</param>
-    /// <returns>returns the mime type of detected otherwise returns null</returns>
-    IImageFormat DetectFormat(ReadOnlySpan<byte> header);
+    /// <param name="format">The mime type of detected otherwise returns null</param>
+    /// <returns>returns true when format was detected otherwise false.</returns>
+    bool TryDetectFormat(ReadOnlySpan<byte> header, [NotNullWhen(true)] out IImageFormat? format);
 }

src/ImageSharp/Formats/ImageDecoderUtilities.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;

src/ImageSharp/Formats/ImageFormatManager.cs

@@ -1,8 +1,8 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Collections.Concurrent;
+using System.Diagnostics.CodeAnalysis;
 
 namespace SixLabors.ImageSharp.Formats;
 
@@ -92,8 +92,9 @@ public class ImageFormatManager
     /// For the specified file extensions type find the e <see cref="IImageFormat"/>.
     /// </summary>
     /// <param name="extension">The extension to discover</param>
-    /// <returns>The <see cref="IImageFormat"/> if found otherwise null</returns>
-    public IImageFormat FindFormatByFileExtension(string extension)
+    /// <param name="format">The <see cref="IImageFormat"/> if found otherwise null</param>
+    /// <returns>False if no format was found</returns>
+    public bool TryFindFormatByFileExtension(string extension, [NotNullWhen(true)] out IImageFormat? format)
     {
         Guard.NotNullOrWhiteSpace(extension, nameof(extension));
 
@@ -102,7 +103,10 @@ public class ImageFormatManager
             extension = extension[1..];
         }
 
-        return this.imageFormats.FirstOrDefault(x => x.FileExtensions.Contains(extension, StringComparer.OrdinalIgnoreCase));
+        format = this.imageFormats.FirstOrDefault(x =>
+            x.FileExtensions.Contains(extension, StringComparer.OrdinalIgnoreCase));
+
+        return format != null;
     }
 
     /// <summary>
@@ -110,7 +114,7 @@ public class ImageFormatManager
     /// </summary>
     /// <param name="mimeType">The mime-type to discover</param>
     /// <returns>The <see cref="IImageFormat"/> if found; otherwise null</returns>
-    public IImageFormat FindFormatByMimeType(string mimeType)
+    public IImageFormat? FindFormatByMimeType(string mimeType)
         => this.imageFormats.FirstOrDefault(x => x.MimeTypes.Contains(mimeType, StringComparer.OrdinalIgnoreCase));
 
     /// <summary>
@@ -160,11 +164,11 @@ public class ImageFormatManager
     /// </summary>
     /// <param name="format">The format to discover</param>
     /// <returns>The <see cref="IImageDecoder"/> if found otherwise null</returns>
-    public IImageDecoder FindDecoder(IImageFormat format)
+    public IImageDecoder? FindDecoder(IImageFormat format)
     {
         Guard.NotNull(format, nameof(format));
 
-        return this.mimeTypeDecoders.TryGetValue(format, out IImageDecoder decoder)
+        return this.mimeTypeDecoders.TryGetValue(format, out IImageDecoder? decoder)
             ? decoder
             : null;
     }
@@ -174,11 +178,11 @@ public class ImageFormatManager
     /// </summary>
     /// <param name="format">The format to discover</param>
     /// <returns>The <see cref="IImageEncoder"/> if found otherwise null</returns>
-    public IImageEncoder FindEncoder(IImageFormat format)
+    public IImageEncoder? FindEncoder(IImageFormat format)
     {
         Guard.NotNull(format, nameof(format));
 
-        return this.mimeTypeEncoders.TryGetValue(format, out IImageEncoder encoder)
+        return this.mimeTypeEncoders.TryGetValue(format, out IImageEncoder? encoder)
             ? encoder
             : null;
     }

src/ImageSharp/Formats/Jpeg/JpegImageFormatDetector.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
+
+using System.Diagnostics.CodeAnalysis;
 
 namespace SixLabors.ImageSharp.Formats.Jpeg;
 
@@ -13,8 +14,11 @@ public sealed class JpegImageFormatDetector : IImageFormatDetector
     public int HeaderSize => 11;
 
     /// <inheritdoc/>
-    public IImageFormat DetectFormat(ReadOnlySpan<byte> header)
-        => this.IsSupportedFileFormat(header) ? JpegFormat.Instance : null;
+    public bool TryDetectFormat(ReadOnlySpan<byte> header, [NotNullWhen(true)] out IImageFormat? format)
+    {
+        format = this.IsSupportedFileFormat(header) ? JpegFormat.Instance : null;
+        return format != null;
+    }
 
     private bool IsSupportedFileFormat(ReadOnlySpan<byte> header)
         => header.Length >= this.HeaderSize

src/ImageSharp/Formats/Pbm/PbmImageFormatDetector.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
+
+using System.Diagnostics.CodeAnalysis;
 
 namespace SixLabors.ImageSharp.Formats.Pbm;
 
@@ -17,7 +18,11 @@ public sealed class PbmImageFormatDetector : IImageFormatDetector
     public int HeaderSize => 2;
 
     /// <inheritdoc/>
-    public IImageFormat DetectFormat(ReadOnlySpan<byte> header) => IsSupportedFileFormat(header) ? PbmFormat.Instance : null;
+    public bool TryDetectFormat(ReadOnlySpan<byte> header, [NotNullWhen(true)] out IImageFormat? format)
+    {
+        format = IsSupportedFileFormat(header) ? PbmFormat.Instance : null;
+        return format != null;
+    }
 
     private static bool IsSupportedFileFormat(ReadOnlySpan<byte> header)
     {

src/ImageSharp/Formats/Png/PngImageFormatDetector.cs

@@ -1,8 +1,8 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Buffers.Binary;
+using System.Diagnostics.CodeAnalysis;
 
 namespace SixLabors.ImageSharp.Formats.Png;
 
@@ -15,9 +15,10 @@ public sealed class PngImageFormatDetector : IImageFormatDetector
     public int HeaderSize => 8;
 
     /// <inheritdoc/>
-    public IImageFormat DetectFormat(ReadOnlySpan<byte> header)
+    public bool TryDetectFormat(ReadOnlySpan<byte> header, [NotNullWhen(true)] out IImageFormat? format)
     {
-        return this.IsSupportedFileFormat(header) ? PngFormat.Instance : null;
+        format = this.IsSupportedFileFormat(header) ? PngFormat.Instance : null;
+        return format != null;
     }
 
     private bool IsSupportedFileFormat(ReadOnlySpan<byte> header)

src/ImageSharp/Formats/Tga/TgaImageFormatDetector.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
+
+using System.Diagnostics.CodeAnalysis;
 
 namespace SixLabors.ImageSharp.Formats.Tga;
 
@@ -13,9 +14,10 @@ public sealed class TgaImageFormatDetector : IImageFormatDetector
     public int HeaderSize => 16;
 
     /// <inheritdoc/>
-    public IImageFormat DetectFormat(ReadOnlySpan<byte> header)
+    public bool TryDetectFormat(ReadOnlySpan<byte> header, [NotNullWhen(true)] out IImageFormat? format)
     {
-        return this.IsSupportedFileFormat(header) ? TgaFormat.Instance : null;
+        format = this.IsSupportedFileFormat(header) ? TgaFormat.Instance : null;
+        return format != null;
     }
 
     private bool IsSupportedFileFormat(ReadOnlySpan<byte> header)

src/ImageSharp/Formats/Tiff/TiffImageFormatDetector.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
+
+using System.Diagnostics.CodeAnalysis;
 
 namespace SixLabors.ImageSharp.Formats.Tiff;
 
@@ -13,14 +14,10 @@ public sealed class TiffImageFormatDetector : IImageFormatDetector
     public int HeaderSize => 8;
 
     /// <inheritdoc/>
-    public IImageFormat DetectFormat(ReadOnlySpan<byte> header)
+    public bool TryDetectFormat(ReadOnlySpan<byte> header, [NotNullWhen(true)] out IImageFormat? format)
     {
-        if (this.IsSupportedFileFormat(header))
-        {
-            return TiffFormat.Instance;
-        }
-
-        return null;
+        format = this.IsSupportedFileFormat(header) ? TiffFormat.Instance : null;
+        return format != null;
     }
 
     private bool IsSupportedFileFormat(ReadOnlySpan<byte> header)

src/ImageSharp/Formats/Webp/WebpImageFormatDetector.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
+
+using System.Diagnostics.CodeAnalysis;
 
 namespace SixLabors.ImageSharp.Formats.Webp;
 
@@ -13,8 +14,11 @@ public sealed class WebpImageFormatDetector : IImageFormatDetector
     public int HeaderSize => 12;
 
     /// <inheritdoc />
-    public IImageFormat DetectFormat(ReadOnlySpan<byte> header)
-        => this.IsSupportedFileFormat(header) ? WebpFormat.Instance : null;
+    public bool TryDetectFormat(ReadOnlySpan<byte> header, [NotNullWhen(true)] out IImageFormat? format)
+    {
+        format = this.IsSupportedFileFormat(header) ? WebpFormat.Instance : null;
+        return format != null;
+    }
 
     private bool IsSupportedFileFormat(ReadOnlySpan<byte> header)
         => header.Length >= this.HeaderSize && IsRiffContainer(header) && IsWebpFile(header);

src/ImageSharp/Image.Decode.cs

@@ -82,8 +82,7 @@ public abstract partial class Image
         {
             if (formatDetector.HeaderSize <= headerSize)
             {
-                IImageFormat attemptFormat = formatDetector.DetectFormat(headersBuffer);
-                if (attemptFormat != null)
+                if (formatDetector.TryDetectFormat(headersBuffer, out IImageFormat attemptFormat))
                 {
                     format = attemptFormat;
                 }

src/ImageSharp/Image.FromBytes.cs

@@ -1,7 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
+using System.Diagnostics.CodeAnalysis;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.PixelFormats;
 
@@ -16,18 +16,20 @@ public abstract partial class Image
     /// By reading the header on the provided byte span this calculates the images format.
     /// </summary>
     /// <param name="data">The byte span containing encoded image data to read the header from.</param>
-    /// <returns>The format or null if none found.</returns>
-    public static IImageFormat DetectFormat(ReadOnlySpan<byte> data)
-        => DetectFormat(DecoderOptions.Default, data);
+    /// <param name="format">The format or null if none found.</param>
+    /// <returns>returns true when format was detected otherwise false.</returns>
+    public static bool TryDetectFormat(ReadOnlySpan<byte> data, [NotNullWhen(true)] out IImageFormat? format)
+        => TryDetectFormat(DecoderOptions.Default, data, out format);
 
     /// <summary>
     /// By reading the header on the provided byte span this calculates the images format.
     /// </summary>
     /// <param name="options">The general decoder options.</param>
     /// <param name="data">The byte span containing encoded image data to read the header from.</param>
+    /// <param name="format">The mime type or null if none found.</param>
     /// <exception cref="ArgumentNullException">The options are null.</exception>
-    /// <returns>The mime type or null if none found.</returns>
-    public static IImageFormat DetectFormat(DecoderOptions options, ReadOnlySpan<byte> data)
+    /// <returns>returns true when format was detected otherwise false.</returns>
+    public static bool TryDetectFormat(DecoderOptions options, ReadOnlySpan<byte> data, [NotNullWhen(true)] out IImageFormat? format)
     {
         Guard.NotNull(options, nameof(options.Configuration));
 
@@ -35,20 +37,20 @@ public abstract partial class Image
         int maxHeaderSize = configuration.MaxHeaderSize;
         if (maxHeaderSize <= 0)
         {
-            return null;
+            format = null;
+            return false;
         }
 
         foreach (IImageFormatDetector detector in configuration.ImageFormatsManager.FormatDetectors)
         {
-            IImageFormat f = detector.DetectFormat(data);
-
-            if (f != null)
+            if (detector.TryDetectFormat(data, out format))
             {
-                return f;
+                return true;
             }
         }
 
-        return default;
+        format = default;
+        return false;
     }
 
     /// <summary>

src/ImageSharp/Image.FromFile.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Diagnostics.CodeAnalysis;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.PixelFormats;
 
@@ -15,23 +16,25 @@ public abstract partial class Image
     /// By reading the header on the provided file this calculates the images mime type.
     /// </summary>
     /// <param name="filePath">The image file to open and to read the header from.</param>
-    /// <returns>The mime type or null if none found.</returns>
-    public static IImageFormat DetectFormat(string filePath)
-        => DetectFormat(DecoderOptions.Default, filePath);
+    /// <param name="format">The mime type or null if none found.</param>
+    /// <returns>returns true when format was detected otherwise false.</returns>
+    public static bool TryDetectFormat(string filePath, [NotNullWhen(true)] out IImageFormat? format)
+        => TryDetectFormat(DecoderOptions.Default, filePath, out format);
 
     /// <summary>
     /// By reading the header on the provided file this calculates the images mime type.
     /// </summary>
     /// <param name="options">The general decoder options.</param>
     /// <param name="filePath">The image file to open and to read the header from.</param>
+    /// <param name="format">The mime type or null if none found.</param>
     /// <exception cref="ArgumentNullException">The configuration is null.</exception>
-    /// <returns>The mime type or null if none found.</returns>
-    public static IImageFormat DetectFormat(DecoderOptions options, string filePath)
+    /// <returns>returns true when format was detected otherwise false.</returns>
+    public static bool TryDetectFormat(DecoderOptions options, string filePath, [NotNullWhen(true)] out IImageFormat? format)
     {
         Guard.NotNull(options, nameof(options));
 
         using Stream file = options.Configuration.FileSystem.OpenRead(filePath);
-        return DetectFormat(options, file);
+        return TryDetectFormat(options, file, out format);
     }
 
     /// <summary>

src/ImageSharp/Image.FromStream.cs

@@ -19,23 +19,28 @@ public abstract partial class Image
     /// By reading the header on the provided stream this calculates the images format type.
     /// </summary>
     /// <param name="stream">The image stream to read the header from.</param>
+    /// <param name="format">The format type or null if none found.</param>
     /// <exception cref="ArgumentNullException">The stream is null.</exception>
     /// <exception cref="NotSupportedException">The stream is not readable.</exception>
-    /// <returns>The format type or null if none found.</returns>
-    public static IImageFormat DetectFormat(Stream stream)
-        => DetectFormat(DecoderOptions.Default, stream);
+    /// <returns>returns true when format was detected otherwise false.</returns>
+    public static bool TryDetectFormat(Stream stream, [NotNullWhen(true)] out IImageFormat? format)
+        => TryDetectFormat(DecoderOptions.Default, stream, out format);
 
     /// <summary>
     /// By reading the header on the provided stream this calculates the images format type.
     /// </summary>
     /// <param name="options">The general decoder options.</param>
     /// <param name="stream">The image stream to read the header from.</param>
+    /// <param name="format">The format type or null if none found.</param>
     /// <exception cref="ArgumentNullException">The options are null.</exception>
     /// <exception cref="ArgumentNullException">The stream is null.</exception>
     /// <exception cref="NotSupportedException">The stream is not readable.</exception>
-    /// <returns>The format type or null if none found.</returns>
-    public static IImageFormat DetectFormat(DecoderOptions options, Stream stream)
-        => WithSeekableStream(options, stream, s => InternalDetectFormat(options.Configuration, s));
+    /// <returns>returns true when format was detected otherwise false.</returns>
+    public static bool TryDetectFormat(DecoderOptions options, Stream stream, [NotNullWhen(true)] out IImageFormat? format)
+    {
+        format = WithSeekableStream(options, stream, s => InternalDetectFormat(options.Configuration, s));
+        return format != null;
+    }
 
     /// <summary>
     /// By reading the header on the provided stream this calculates the images format type.

src/ImageSharp/Image{TPixel}.cs

@@ -1,8 +1,6 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
-using System.Buffers;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using SixLabors.ImageSharp.Advanced;
@@ -420,7 +418,7 @@ public sealed class Image<TPixel> : Image
     {
         Guard.NotNull(frames, nameof(frames));
 
-        ImageFrame<TPixel> rootFrame = frames.FirstOrDefault();
+        ImageFrame<TPixel>? rootFrame = frames.FirstOrDefault();
 
         if (rootFrame == null)
         {

src/ImageSharp/Processing/Processors/CloningImageProcessor{TPixel}.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using SixLabors.ImageSharp.PixelFormats;
 
@@ -73,7 +72,7 @@ public abstract class CloningImageProcessor<TPixel> : ICloningImageProcessor<TPi
         // Create an interim clone of the source image to operate on.
         // Doing this allows for the application of transforms that will alter
         // the dimensions of the image.
-        Image<TPixel> clone = default;
+        Image<TPixel>? clone = default;
         try
         {
             clone = ((ICloningImageProcessor<TPixel>)this).CloneAndExecute();

src/ImageSharp/Processing/Processors/Convolution/ConvolutionProcessorHelpers.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
+
+using System.Diagnostics.CodeAnalysis;
 
 namespace SixLabors.ImageSharp.Processing.Processors.Convolution;
 
@@ -99,7 +100,7 @@ internal static class ConvolutionProcessorHelpers
     /// <param name="row">The resulting 1D row vector, if possible.</param>
     /// <param name="column">The resulting 1D column vector, if possible.</param>
     /// <returns>Whether or not <paramref name="matrix"/> was linearly separable.</returns>
-    public static bool TryGetLinearlySeparableComponents(this DenseMatrix<float> matrix, out float[] row, out float[] column)
+    public static bool TryGetLinearlySeparableComponents(this DenseMatrix<float> matrix, [NotNullWhen(true)] out float[]? row, [NotNullWhen(true)] out float[]? column)
     {
         int height = matrix.Rows;
         int width = matrix.Columns;

src/ImageSharp/Processing/Processors/Convolution/Kernels/EdgeDetector2DKernel.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 namespace SixLabors.ImageSharp.Processing.Processors.Convolution;
 
@@ -88,7 +87,7 @@ public readonly struct EdgeDetector2DKernel : IEquatable<EdgeDetector2DKernel>
         => !(left == right);
 
     /// <inheritdoc/>
-    public override bool Equals(object obj)
+    public override bool Equals(object? obj)
         => obj is EdgeDetector2DKernel kernel && this.Equals(kernel);
 
     /// <inheritdoc/>

src/ImageSharp/Processing/Processors/Convolution/Kernels/EdgeDetectorCompassKernel.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 namespace SixLabors.ImageSharp.Processing.Processors.Convolution;
 
@@ -135,7 +134,7 @@ public readonly struct EdgeDetectorCompassKernel : IEquatable<EdgeDetectorCompas
         => !(left == right);
 
     /// <inheritdoc/>
-    public override bool Equals(object obj) => obj is EdgeDetectorCompassKernel kernel && this.Equals(kernel);
+    public override bool Equals(object? obj) => obj is EdgeDetectorCompassKernel kernel && this.Equals(kernel);
 
     /// <inheritdoc/>
     public bool Equals(EdgeDetectorCompassKernel other) => this.North.Equals(other.North) && this.NorthWest.Equals(other.NorthWest) && this.West.Equals(other.West) && this.SouthWest.Equals(other.SouthWest) && this.South.Equals(other.South) && this.SouthEast.Equals(other.SouthEast) && this.East.Equals(other.East) && this.NorthEast.Equals(other.NorthEast);

src/ImageSharp/Processing/Processors/Convolution/Kernels/EdgeDetectorKernel.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 namespace SixLabors.ImageSharp.Processing.Processors.Convolution;
 
@@ -64,7 +63,7 @@ public readonly struct EdgeDetectorKernel : IEquatable<EdgeDetectorKernel>
         => !(left == right);
 
     /// <inheritdoc/>
-    public override bool Equals(object obj)
+    public override bool Equals(object? obj)
         => obj is EdgeDetectorKernel kernel && this.Equals(kernel);
 
     /// <inheritdoc/>

src/ImageSharp/Processing/Processors/Convolution/Parameters/BokehBlurParameters.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 namespace SixLabors.ImageSharp.Processing.Processors.Convolution.Parameters;
 
@@ -37,7 +36,7 @@ internal readonly struct BokehBlurParameters : IEquatable<BokehBlurParameters>
     }
 
     /// <inheritdoc/>
-    public override bool Equals(object obj) => obj is BokehBlurParameters other && this.Equals(other);
+    public override bool Equals(object? obj) => obj is BokehBlurParameters other && this.Equals(other);
 
     /// <inheritdoc/>
     public override int GetHashCode()

src/ImageSharp/Processing/Processors/Dithering/ErrorDither.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Numerics;
 using System.Runtime.CompilerServices;
@@ -212,7 +211,7 @@ public readonly partial struct ErrorDither : IDither, IEquatable<ErrorDither>, I
     }
 
     /// <inheritdoc/>
-    public override bool Equals(object obj)
+    public override bool Equals(object? obj)
         => obj is ErrorDither dither && this.Equals(dither);
 
     /// <inheritdoc/>
@@ -220,8 +219,8 @@ public readonly partial struct ErrorDither : IDither, IEquatable<ErrorDither>, I
         => this.offset == other.offset && this.matrix.Equals(other.matrix);
 
     /// <inheritdoc/>
-    public bool Equals(IDither other)
-        => this.Equals((object)other);
+    public bool Equals(IDither? other)
+        => this.Equals((object?)other);
 
     /// <inheritdoc/>
     public override int GetHashCode()

src/ImageSharp/Processing/Processors/Dithering/OrderedDither.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Runtime.CompilerServices;
 using SixLabors.ImageSharp.Memory;
@@ -200,7 +199,7 @@ public readonly partial struct OrderedDither : IDither, IEquatable<OrderedDither
     }
 
     /// <inheritdoc/>
-    public override bool Equals(object obj)
+    public override bool Equals(object? obj)
         => obj is OrderedDither dither && this.Equals(dither);
 
     /// <inheritdoc/>
@@ -209,8 +208,8 @@ public readonly partial struct OrderedDither : IDither, IEquatable<OrderedDither
         => this.thresholdMatrix.Equals(other.thresholdMatrix) && this.modulusX == other.modulusX && this.modulusY == other.modulusY;
 
     /// <inheritdoc/>
-    public bool Equals(IDither other)
-        => this.Equals((object)other);
+    public bool Equals(IDither? other)
+        => this.Equals((object?)other);
 
     /// <inheritdoc/>
     [MethodImpl(InliningOptions.ShortMethod)]

src/ImageSharp/Processing/Processors/Dithering/PaletteDitherProcessor{TPixel}.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Buffers;
 using System.Diagnostics.CodeAnalysis;
@@ -19,7 +18,7 @@ internal sealed class PaletteDitherProcessor<TPixel> : ImageProcessor<TPixel>
 {
     private readonly DitherProcessor ditherProcessor;
     private readonly IDither dither;
-    private IMemoryOwner<TPixel> paletteOwner;
+    private IMemoryOwner<TPixel>? paletteOwner;
     private bool isDisposed;
 
     /// <summary>
@@ -62,7 +61,7 @@ internal sealed class PaletteDitherProcessor<TPixel> : ImageProcessor<TPixel>
         this.isDisposed = true;
         if (disposing)
         {
-            this.paletteOwner.Dispose();
+            this.paletteOwner?.Dispose();
             this.ditherProcessor.Dispose();
         }
 

src/ImageSharp/Processing/Processors/Transforms/Resize/ResizeHelper.cs

@@ -1,7 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
+using System.Diagnostics.CodeAnalysis;
 using System.Numerics;
 
 namespace SixLabors.ImageSharp.Processing.Processors.Transforms;
@@ -422,6 +422,7 @@ internal static class ResizeHelper
         return (new Size(Sanitize(width), Sanitize(height)), new Rectangle(targetX, targetY, Sanitize(targetWidth), Sanitize(targetHeight)));
     }
 
+    [DoesNotReturn]
     private static void ThrowInvalid(string message) => throw new InvalidOperationException(message);
 
     private static int Sanitize(int input) => Math.Max(1, input);

tests/ImageSharp.Tests/Formats/ImageFormatManagerTests.cs

@@ -122,7 +122,13 @@ public class ImageFormatManagerTests
 
         byte[] invalidImage = { 1, 2, 3 };
 
-        Assert.Equal(Image.DetectFormat(jpegImage), JpegFormat.Instance);
-        Assert.True(Image.DetectFormat(invalidImage) is null);
+        bool resultValidImage = Image.TryDetectFormat(jpegImage, out IImageFormat format);
+
+        bool resultInvalidImage = Image.TryDetectFormat(invalidImage, out IImageFormat formatInvalid);
+
+        Assert.True(resultValidImage);
+        Assert.Equal(format, JpegFormat.Instance);
+        Assert.False(resultInvalidImage);
+        Assert.True(formatInvalid is null);
     }
 }

tests/ImageSharp.Tests/Image/ImageFrameCollectionTests.Generic.cs

@@ -38,7 +38,7 @@ public abstract partial class ImageFrameCollectionTests
                     using ImageFrame<Rgba32> addedFrame = this.Collection.AddFrame((ImageFrame<Rgba32>)null);
                 });
 
-            Assert.StartsWith("Parameter \"frame\" must be not null.", ex.Message);
+            Assert.StartsWith("Value cannot be null. (Parameter 'frame')", ex.Message);
         }
 
         [Fact]
@@ -52,7 +52,7 @@ public abstract partial class ImageFrameCollectionTests
                     using ImageFrame<Rgba32> addedFrame = this.Collection.AddFrame(data);
                 });
 
-            Assert.StartsWith("Parameter \"source\" must be not null.", ex.Message);
+            Assert.StartsWith("Value cannot be null. (Parameter 'source')", ex.Message);
         }
 
         [Fact]
@@ -89,7 +89,7 @@ public abstract partial class ImageFrameCollectionTests
                     using ImageFrame<Rgba32> insertedFrame = this.Collection.InsertFrame(1, null);
                 });
 
-            Assert.StartsWith("Parameter \"frame\" must be not null.", ex.Message);
+            Assert.StartsWith("Value cannot be null. (Parameter 'frame')", ex.Message);
         }
 
         [Fact]

tests/ImageSharp.Tests/Image/ImageFrameCollectionTests.NonGeneric.cs

@@ -77,7 +77,7 @@ public abstract partial class ImageFrameCollectionTests
             ArgumentNullException ex = Assert.Throws<ArgumentNullException>(
                 () => this.Collection.AddFrame(null));
 
-            Assert.StartsWith("Parameter \"source\" must be not null.", ex.Message);
+            Assert.StartsWith("Value cannot be null. (Parameter 'source')", ex.Message);
         }
 
         [Fact]
@@ -95,7 +95,7 @@ public abstract partial class ImageFrameCollectionTests
             ArgumentNullException ex = Assert.Throws<ArgumentNullException>(
                 () => this.Collection.InsertFrame(1, null));
 
-            Assert.StartsWith("Parameter \"source\" must be not null.", ex.Message);
+            Assert.StartsWith("Value cannot be null. (Parameter 'source')", ex.Message);
         }
 
         [Fact]

tests/ImageSharp.Tests/Image/ImageTests.DetectFormat.cs

@@ -22,14 +22,21 @@ public partial class ImageTests
 
         private IImageFormat LocalImageFormat => this.localImageFormatMock.Object;
 
-        private static readonly IImageFormat ExpectedGlobalFormat =
-            Configuration.Default.ImageFormatsManager.FindFormatByFileExtension("bmp");
+        private static IImageFormat ExpectedGlobalFormat
+        {
+            get
+            {
+                Configuration.Default.ImageFormatsManager.TryFindFormatByFileExtension("bmp", out IImageFormat format);
+                return format!;
+            }
+        }
 
         [Fact]
         public void FromBytes_GlobalConfiguration()
         {
-            IImageFormat type = Image.DetectFormat(this.ActualImageSpan);
+            bool result = Image.TryDetectFormat(this.ActualImageSpan, out IImageFormat type);
 
+            Assert.True(result);
             Assert.Equal(ExpectedGlobalFormat, type);
         }
 
@@ -41,15 +48,18 @@ public partial class ImageTests
                 Configuration = this.LocalConfiguration
             };
 
-            IImageFormat type = Image.DetectFormat(options, this.ByteArray);
+            bool result = Image.TryDetectFormat(options, this.ByteArray, out IImageFormat type);
 
+            Assert.True(result);
             Assert.Equal(this.LocalImageFormat, type);
         }
 
         [Fact]
         public void FromFileSystemPath_GlobalConfiguration()
         {
-            IImageFormat type = Image.DetectFormat(ActualImagePath);
+            bool result = Image.TryDetectFormat(ActualImagePath, out IImageFormat type);
+
+            Assert.True(result);
             Assert.Equal(ExpectedGlobalFormat, type);
         }
 
@@ -61,7 +71,9 @@ public partial class ImageTests
                 Configuration = this.LocalConfiguration
             };
 
-            IImageFormat type = Image.DetectFormat(options, this.MockFilePath);
+            bool result = Image.TryDetectFormat(options, this.MockFilePath, out IImageFormat type);
+
+            Assert.True(result);
             Assert.Equal(this.LocalImageFormat, type);
         }
 
@@ -70,7 +82,9 @@ public partial class ImageTests
         {
             using (var stream = new MemoryStream(this.ActualImageBytes))
             {
-                IImageFormat type = Image.DetectFormat(stream);
+                bool result = Image.TryDetectFormat(stream, out IImageFormat type);
+
+                Assert.True(result);
                 Assert.Equal(ExpectedGlobalFormat, type);
             }
         }
@@ -83,7 +97,9 @@ public partial class ImageTests
                 Configuration = this.LocalConfiguration
             };
 
-            IImageFormat type = Image.DetectFormat(options, this.DataStream);
+            bool result = Image.TryDetectFormat(options, this.DataStream, out IImageFormat type);
+
+            Assert.True(result);
             Assert.Equal(this.LocalImageFormat, type);
         }
 
@@ -95,7 +111,9 @@ public partial class ImageTests
                 Configuration = new()
             };
 
-            IImageFormat type = Image.DetectFormat(options, this.DataStream);
+            bool result = Image.TryDetectFormat(options, this.DataStream, out IImageFormat type);
+
+            Assert.False(result);
             Assert.Null(type);
         }
 

tests/ImageSharp.Tests/Image/ImageTests.Identify.cs

@@ -25,8 +25,15 @@ public partial class ImageTests
 
         private IImageFormat LocalImageFormat => this.localImageFormatMock.Object;
 
-        private static readonly IImageFormat ExpectedGlobalFormat =
-            Configuration.Default.ImageFormatsManager.FindFormatByFileExtension("bmp");
+        private static IImageFormat ExpectedGlobalFormat
+        {
+            get
+            {
+                Configuration.Default.ImageFormatsManager.TryFindFormatByFileExtension("bmp", out var format);
+                return format!;
+            }
+        }
+
 
         [Fact]
         public void FromBytes_GlobalConfiguration()
@@ -40,10 +47,7 @@ public partial class ImageTests
         [Fact]
         public void FromBytes_CustomConfiguration()
         {
-            DecoderOptions options = new()
-            {
-                Configuration = this.LocalConfiguration
-            };
+            DecoderOptions options = new() { Configuration = this.LocalConfiguration };
 
             IImageInfo info = Image.Identify(options, this.ByteArray, out IImageFormat type);
 
@@ -63,10 +67,7 @@ public partial class ImageTests
         [Fact]
         public void FromFileSystemPath_CustomConfiguration()
         {
-            DecoderOptions options = new()
-            {
-                Configuration = this.LocalConfiguration
-            };
+            DecoderOptions options = new() { Configuration = this.LocalConfiguration };
 
             IImageInfo info = Image.Identify(options, this.MockFilePath, out IImageFormat type);
 
@@ -119,10 +120,7 @@ public partial class ImageTests
         [Fact]
         public void FromStream_CustomConfiguration()
         {
-            DecoderOptions options = new()
-            {
-                Configuration = this.LocalConfiguration
-            };
+            DecoderOptions options = new() { Configuration = this.LocalConfiguration };
 
             IImageInfo info = Image.Identify(options, this.DataStream, out IImageFormat type);
 
@@ -133,10 +131,7 @@ public partial class ImageTests
         [Fact]
         public void FromStream_CustomConfiguration_NoFormat()
         {
-            DecoderOptions options = new()
-            {
-                Configuration = this.LocalConfiguration
-            };
+            DecoderOptions options = new() { Configuration = this.LocalConfiguration };
 
             IImageInfo info = Image.Identify(options, this.DataStream);
 
@@ -146,10 +141,7 @@ public partial class ImageTests
         [Fact]
         public void WhenNoMatchingFormatFound_ReturnsNull()
         {
-            DecoderOptions options = new()
-            {
-                Configuration = new()
-            };
+            DecoderOptions options = new() { Configuration = new() };
 
             IImageInfo info = Image.Identify(options, this.DataStream, out IImageFormat type);
 
@@ -164,18 +156,15 @@ public partial class ImageTests
             using var zipFile = new ZipArchive(new MemoryStream(
                 new byte[]
                 {
-                    0x50, 0x4B, 0x03, 0x04, 0x0A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x77, 0xAF,
-                    0x94, 0x53, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-                    0x00, 0x00, 0x07, 0x00, 0x00, 0x00, 0x6D, 0x79, 0x73, 0x74, 0x65, 0x72,
-                    0x79, 0x50, 0x4B, 0x01, 0x02, 0x3F, 0x00, 0x0A, 0x00, 0x00, 0x00, 0x00,
-                    0x00, 0x77, 0xAF, 0x94, 0x53, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-                    0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0x00, 0x24, 0x00, 0x00, 0x00, 0x00,
-                    0x00, 0x00, 0x00, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x6D,
-                    0x79, 0x73, 0x74, 0x65, 0x72, 0x79, 0x0A, 0x00, 0x20, 0x00, 0x00, 0x00,
-                    0x00, 0x00, 0x01, 0x00, 0x18, 0x00, 0x46, 0x82, 0xFF, 0x91, 0x27, 0xF6,
-                    0xD7, 0x01, 0x55, 0xA1, 0xF9, 0x91, 0x27, 0xF6, 0xD7, 0x01, 0x55, 0xA1,
-                    0xF9, 0x91, 0x27, 0xF6, 0xD7, 0x01, 0x50, 0x4B, 0x05, 0x06, 0x00, 0x00,
-                    0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x59, 0x00, 0x00, 0x00, 0x25, 0x00,
+                    0x50, 0x4B, 0x03, 0x04, 0x0A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x77, 0xAF, 0x94, 0x53, 0x00, 0x00,
+                    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0x00, 0x00, 0x00, 0x6D, 0x79,
+                    0x73, 0x74, 0x65, 0x72, 0x79, 0x50, 0x4B, 0x01, 0x02, 0x3F, 0x00, 0x0A, 0x00, 0x00, 0x00, 0x00,
+                    0x00, 0x77, 0xAF, 0x94, 0x53, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                    0x00, 0x07, 0x00, 0x24, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x00, 0x00, 0x00, 0x00,
+                    0x00, 0x00, 0x00, 0x6D, 0x79, 0x73, 0x74, 0x65, 0x72, 0x79, 0x0A, 0x00, 0x20, 0x00, 0x00, 0x00,
+                    0x00, 0x00, 0x01, 0x00, 0x18, 0x00, 0x46, 0x82, 0xFF, 0x91, 0x27, 0xF6, 0xD7, 0x01, 0x55, 0xA1,
+                    0xF9, 0x91, 0x27, 0xF6, 0xD7, 0x01, 0x55, 0xA1, 0xF9, 0x91, 0x27, 0xF6, 0xD7, 0x01, 0x50, 0x4B,
+                    0x05, 0x06, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x59, 0x00, 0x00, 0x00, 0x25, 0x00,
                     0x00, 0x00, 0x00, 0x00
                 }));
             using Stream stream = zipFile.Entries[0].Open();
@@ -236,18 +225,15 @@ public partial class ImageTests
             using var zipFile = new ZipArchive(new MemoryStream(
                 new byte[]
                 {
-                    0x50, 0x4B, 0x03, 0x04, 0x0A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x77, 0xAF,
-                    0x94, 0x53, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-                    0x00, 0x00, 0x07, 0x00, 0x00, 0x00, 0x6D, 0x79, 0x73, 0x74, 0x65, 0x72,
-                    0x79, 0x50, 0x4B, 0x01, 0x02, 0x3F, 0x00, 0x0A, 0x00, 0x00, 0x00, 0x00,
-                    0x00, 0x77, 0xAF, 0x94, 0x53, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-                    0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0x00, 0x24, 0x00, 0x00, 0x00, 0x00,
-                    0x00, 0x00, 0x00, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x6D,
-                    0x79, 0x73, 0x74, 0x65, 0x72, 0x79, 0x0A, 0x00, 0x20, 0x00, 0x00, 0x00,
-                    0x00, 0x00, 0x01, 0x00, 0x18, 0x00, 0x46, 0x82, 0xFF, 0x91, 0x27, 0xF6,
-                    0xD7, 0x01, 0x55, 0xA1, 0xF9, 0x91, 0x27, 0xF6, 0xD7, 0x01, 0x55, 0xA1,
-                    0xF9, 0x91, 0x27, 0xF6, 0xD7, 0x01, 0x50, 0x4B, 0x05, 0x06, 0x00, 0x00,
-                    0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x59, 0x00, 0x00, 0x00, 0x25, 0x00,
+                    0x50, 0x4B, 0x03, 0x04, 0x0A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x77, 0xAF, 0x94, 0x53, 0x00, 0x00,
+                    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0x00, 0x00, 0x00, 0x6D, 0x79,
+                    0x73, 0x74, 0x65, 0x72, 0x79, 0x50, 0x4B, 0x01, 0x02, 0x3F, 0x00, 0x0A, 0x00, 0x00, 0x00, 0x00,
+                    0x00, 0x77, 0xAF, 0x94, 0x53, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                    0x00, 0x07, 0x00, 0x24, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x00, 0x00, 0x00, 0x00,
+                    0x00, 0x00, 0x00, 0x6D, 0x79, 0x73, 0x74, 0x65, 0x72, 0x79, 0x0A, 0x00, 0x20, 0x00, 0x00, 0x00,
+                    0x00, 0x00, 0x01, 0x00, 0x18, 0x00, 0x46, 0x82, 0xFF, 0x91, 0x27, 0xF6, 0xD7, 0x01, 0x55, 0xA1,
+                    0xF9, 0x91, 0x27, 0xF6, 0xD7, 0x01, 0x55, 0xA1, 0xF9, 0x91, 0x27, 0xF6, 0xD7, 0x01, 0x50, 0x4B,
+                    0x05, 0x06, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x59, 0x00, 0x00, 0x00, 0x25, 0x00,
                     0x00, 0x00, 0x00, 0x00
                 }));
             using Stream stream = zipFile.Entries[0].Open();
@@ -258,10 +244,7 @@ public partial class ImageTests
         [Fact]
         public async Task FromPathAsync_CustomConfiguration()
         {
-            DecoderOptions options = new()
-            {
-                Configuration = this.LocalConfiguration
-            };
+            DecoderOptions options = new() { Configuration = this.LocalConfiguration };
 
             IImageInfo info = await Image.IdentifyAsync(options, this.MockFilePath);
             Assert.Equal(this.LocalImageInfo, info);
@@ -270,12 +253,10 @@ public partial class ImageTests
         [Fact]
         public async Task IdentifyWithFormatAsync_FromPath_CustomConfiguration()
         {
-            DecoderOptions options = new()
-            {
-                Configuration = this.LocalConfiguration
-            };
+            DecoderOptions options = new() { Configuration = this.LocalConfiguration };
 
-            (IImageInfo ImageInfo, IImageFormat Format) info = await Image.IdentifyWithFormatAsync(options, this.MockFilePath);
+            (IImageInfo ImageInfo, IImageFormat Format) info =
+                await Image.IdentifyWithFormatAsync(options, this.MockFilePath);
             Assert.NotNull(info.ImageInfo);
             Assert.Equal(this.LocalImageFormat, info.Format);
         }
@@ -300,13 +281,11 @@ public partial class ImageTests
         [Fact]
         public async Task FromStreamAsync_CustomConfiguration()
         {
-            DecoderOptions options = new()
-            {
-                Configuration = this.LocalConfiguration
-            };
+            DecoderOptions options = new() { Configuration = this.LocalConfiguration };
 
             var asyncStream = new AsyncStreamWrapper(this.DataStream, () => false);
-            (IImageInfo ImageInfo, IImageFormat Format) info = await Image.IdentifyWithFormatAsync(options, asyncStream);
+            (IImageInfo ImageInfo, IImageFormat Format)
+                info = await Image.IdentifyWithFormatAsync(options, asyncStream);
 
             Assert.Equal(this.LocalImageInfo, info.ImageInfo);
             Assert.Equal(this.LocalImageFormat, info.Format);
@@ -315,13 +294,11 @@ public partial class ImageTests
         [Fact]
         public async Task WhenNoMatchingFormatFoundAsync_ReturnsNull()
         {
-            DecoderOptions options = new()
-            {
-                Configuration = new()
-            };
+            DecoderOptions options = new() { Configuration = new() };
 
             var asyncStream = new AsyncStreamWrapper(this.DataStream, () => false);
-            (IImageInfo ImageInfo, IImageFormat Format) info = await Image.IdentifyWithFormatAsync(options, asyncStream);
+            (IImageInfo ImageInfo, IImageFormat Format)
+                info = await Image.IdentifyWithFormatAsync(options, asyncStream);
 
             Assert.Null(info.ImageInfo);
         }

tests/ImageSharp.Tests/Image/ImageTests.SaveAsync.cs

@@ -77,8 +77,8 @@ public partial class ImageTests
             using (var image = new Image<Rgba32>(5, 5))
             {
                 string ext = Path.GetExtension(filename);
-                IImageFormat format = image.GetConfiguration().ImageFormatsManager.FindFormatByFileExtension(ext);
-                Assert.Equal(mimeType, format.DefaultMimeType);
+                image.GetConfiguration().ImageFormatsManager.TryFindFormatByFileExtension(ext, out IImageFormat format);
+                Assert.Equal(mimeType, format!.DefaultMimeType);
 
                 using (var stream = new MemoryStream())
                 {

tests/ImageSharp.Tests/Image/LargeImageIntegrationTests.cs

@@ -55,8 +55,8 @@ public class LargeImageIntegrationTests
 
             Configuration configuration = Configuration.Default.Clone();
             configuration.PreferContiguousImageBuffers = true;
-            IImageEncoder encoder = configuration.ImageFormatsManager.FindEncoder(
-                configuration.ImageFormatsManager.FindFormatByFileExtension(formatInner));
+            configuration.ImageFormatsManager.TryFindFormatByFileExtension(formatInner, out IImageFormat format);
+            IImageEncoder encoder = configuration.ImageFormatsManager.FindEncoder(format!);
             string dir = TestEnvironment.CreateOutputDirectory(".Temp");
             string path = Path.Combine(dir, $"{Guid.NewGuid()}.{formatInner}");
             using (Image<Rgba32> temp = new(2048, 2048))

tests/ImageSharp.Tests/Image/MockImageFormatDetector.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Diagnostics.CodeAnalysis;
 using SixLabors.ImageSharp.Formats;
 
 namespace SixLabors.ImageSharp.Tests;
@@ -19,8 +20,10 @@ public class MockImageFormatDetector : IImageFormatDetector
 
     public int HeaderSize => 1;
 
-    public IImageFormat DetectFormat(ReadOnlySpan<byte> header)
+    public bool TryDetectFormat(ReadOnlySpan<byte> header, [NotNullWhen(true)] out IImageFormat? format)
     {
-        return this.localImageFormatMock;
+        format = this.localImageFormatMock;
+
+        return true;
     }
 }

tests/ImageSharp.Tests/TestFormat.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Diagnostics.CodeAnalysis;
 using System.Numerics;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.PixelFormats;
@@ -174,14 +175,11 @@ public class TestFormat : IImageFormatConfigurationModule, IImageFormat
 
         public int HeaderSize => this.testFormat.HeaderSize;
 
-        public IImageFormat DetectFormat(ReadOnlySpan<byte> header)
+        public bool TryDetectFormat(ReadOnlySpan<byte> header, [NotNullWhen(true)] out IImageFormat? format)
         {
-            if (this.testFormat.IsSupportedFileFormat(header))
-            {
-                return this.testFormat;
-            }
+            format = this.testFormat.IsSupportedFileFormat(header) ? this.testFormat : null;
 
-            return null;
+            return format != null;
         }
 
         public TestHeader(TestFormat testFormat) => this.testFormat = testFormat;

tests/ImageSharp.Tests/TestUtilities/TestEnvironment.Formats.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Diagnostics.CodeAnalysis;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Bmp;
 using SixLabors.ImageSharp.Formats.Gif;
@@ -36,7 +37,9 @@ public static partial class TestEnvironment
     {
         string extension = Path.GetExtension(filePath);
 
-        return Configuration.ImageFormatsManager.FindFormatByFileExtension(extension);
+        Configuration.ImageFormatsManager.TryFindFormatByFileExtension(extension, out IImageFormat format);
+
+        return format;
     }
 
     private static void ConfigureCodecs(