Changes from Review

* Throw InvalidImageContentException
* Change GetDesctiption to TryGetDescription
* Do not throw when creating exifvalue and adding it to ifdValues

Author: stefannikolei

src/ImageSharp/Formats/Tiff/TiffDecoderCore.cs

@@ -793,7 +793,7 @@ private static int GetImageWidth(ExifProfile exifProfile)
     {
         if (!exifProfile.TryGetValue(ExifTag.ImageWidth, out IExifValue<Number> width))
         {
-            TiffThrowHelper.ThrowImageFormatException("The TIFF image frame is missing the ImageWidth");
+            TiffThrowHelper.ThrowInvalidImageContentException("The TIFF image frame is missing the ImageWidth");
         }
 
         DebugGuard.MustBeLessThanOrEqualTo((ulong)width.Value, (ulong)int.MaxValue, nameof(ExifTag.ImageWidth));

src/ImageSharp/Formats/Tiff/TiffThrowHelper.cs

@@ -10,6 +10,9 @@ internal static class TiffThrowHelper
     [DoesNotReturn]
     public static Exception ThrowImageFormatException(string errorMessage) => throw new ImageFormatException(errorMessage);
 
+    [DoesNotReturn]
+    public static Exception ThrowInvalidImageContentException(string errorMessage) => throw new InvalidImageContentException(errorMessage);
+
     [DoesNotReturn]
     public static Exception NotSupportedDecompressor(string compressionType) => throw new NotSupportedException($"Not supported decoder compression method: {compressionType}");
 

src/ImageSharp/Metadata/Profiles/Exif/ExifTagDescriptionAttribute.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 
 namespace SixLabors.ImageSharp.Metadata.Profiles.Exif;
@@ -25,17 +26,20 @@ public ExifTagDescriptionAttribute(object value, string description)
     /// </summary>
     /// <param name="tag">The tag.</param>
     /// <param name="value">The value.</param>
+    /// <param name="description">The description.</param>
     /// <returns>
-    /// The <see cref="string"/>.
+    /// True when description was found
     /// </returns>
-    public static string? GetDescription(ExifTag tag, object? value)
+    public static bool TryGetDescription(ExifTag tag, object? value, [NotNullWhen(true)] out string? description)
     {
-        var tagValue = (ExifTagValue)(ushort)tag;
+        ExifTagValue tagValue = (ExifTagValue)(ushort)tag;
         FieldInfo? field = typeof(ExifTagValue).GetField(tagValue.ToString(), BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static);
 
+        description = null;
+
         if (field is null)
         {
-            return null;
+            return false;
         }
 
         foreach (CustomAttributeData customAttribute in field.CustomAttributes)
@@ -44,10 +48,12 @@ public ExifTagDescriptionAttribute(object value, string description)
 
             if (Equals(attributeValue, value))
             {
-                return (string?)customAttribute.ConstructorArguments[1].Value;
+                description = (string?)customAttribute.ConstructorArguments[1].Value;
+
+                return description is not null;
             }
         }
 
-        return null;
+        return false;
     }
 }

src/ImageSharp/Metadata/Profiles/Exif/ExifWriter.cs

@@ -179,9 +179,11 @@ private static int WriteInt32(int value, Span<byte> destination, int offset)
             }
 
             ExifValue? result = ExifValues.Create(offset);
-            Guard.NotNull(result);
 
-            ifdValues.Add(result);
+            if (result is not null)
+            {
+                ifdValues.Add(result);
+            }
 
             return result;
         }

src/ImageSharp/Metadata/Profiles/Exif/Values/ExifValue{TValueType}.cs

@@ -48,9 +48,5 @@ public override bool TrySetValue(object? value)
         return false;
     }
 
-    public override string? ToString()
-    {
-        string? description = ExifTagDescriptionAttribute.GetDescription(this.Tag, this.Value);
-        return description ?? this.StringValue;
-    }
+    public override string? ToString() => ExifTagDescriptionAttribute.TryGetDescription(this.Tag, this.Value, out string? description) ? description : this.StringValue;
 }