fix(368): remediate nullable-reference debt in SVGControl/ via per-file opt-in

SVGControl/ButtonSVG.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.ComponentModel;
 using System.Globalization;
 using System.IO;
@@ -52,7 +53,7 @@ private void ImageSVG_PropertyChanged(object sender, PropertyChangedEventArgs e)
             //this.Image = ImageSVG.Render();
         }
 
-        public static byte[] ObjectToByteArray(Object obj)
+        public static byte[] ObjectToByteArray(object? obj)
         {
             BinaryFormatter bf = new BinaryFormatter();
             using (var ms = new MemoryStream())
@@ -73,7 +74,7 @@ private void ButtonSVG_ParentChanged(object sender, EventArgs e)
             //ImageSVG.ResourceNames = names;
         }
 
-        private static string GetStringForValue(object value)
+        private static string GetStringForValue(object? value)
         {
             if (value == null)
                 return "null";

SVGControl/DropDownEditor.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.ComponentModel.Design;
@@ -18,7 +19,7 @@ namespace SVGControl
     // used by the property grid to display item in edit mode
     public class DropDownEditor : UITypeEditor
     {
-        private IWindowsFormsEditorService _editorService;
+        private IWindowsFormsEditorService? _editorService;
 
         public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context)
         {
@@ -32,10 +33,12 @@ public override object EditValue(
             object value
         )
         {
-            IDesignerHost host = provider.GetService(typeof(IDesignerHost)) as IDesignerHost;
+            // Null-forgiving preserves the pre-existing NRE-on-null behavior at
+            // host.RootComponentClassName if the service is unavailable.
+            IDesignerHost host = (provider.GetService(typeof(IDesignerHost)) as IDesignerHost)!;
             string typName = host.RootComponentClassName;
             Type typ = host.GetType(typName);
-            Assembly asm = null;
+            Assembly? asm = null;
             if (typ == null)
             {
                 MessageBox.Show("Please build project before attempting to set this property");

SVGControl/ISvgResource.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Linq;
@@ -10,8 +11,8 @@ namespace SVGControl
     [TypeConverter(typeof(SvgResourceConverter))]
     public interface ISvgResource
     {
-        string Name { get; }
-        byte[] Data { get; }
+        string? Name { get; }
+        byte[]? Data { get; }
     }
 
     public class SvgResource : ISvgResource
@@ -24,7 +25,7 @@ public SvgResource(string name, byte[] data)
             Data = data;
         }
 
-        public string Name { get; set; }
-        public byte[] Data { get; set; }
+        public string? Name { get; set; }
+        public byte[]? Data { get; set; }
     }
 }

SVGControl/PictureBoxSVG.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Data;

SVGControl/SVGFileNameEditor.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.IO;
@@ -12,8 +13,8 @@ internal class SvgFileNameEditor : FileNameEditor
         private string _currentValue = string.Empty;
         private string _absoluteFilepath = string.Empty;
         private string _fileName = string.Empty;
-        private string _appPath;
-        private OpenFileDialog _ofd;
+        private string _appPath = string.Empty;
+        private OpenFileDialog? _ofd;
 
         public SvgFileNameEditor()
         {

SVGControl/SVGParser.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.Drawing;
 using System.IO;

SVGControl/SvgImageSelector.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics;
@@ -52,13 +53,13 @@ public SvgImageSelector(Size outer, Padding margin, AutoSize autoSize, bool useD
         }
 
         //private SvgDocument _doc;
-        private string _relativeImagePath;
-        private string _absoluteImagePath;
+        private string? _relativeImagePath;
+        private string? _absoluteImagePath;
         private bool _saveRendering = false;
         private bool _useDefaultImage = false;
         private SvgRenderer _renderer;
 
-        internal String AboluteImagePath
+        internal String? AboluteImagePath
         {
             get { return _absoluteImagePath; }
         }
@@ -77,7 +78,14 @@ public string ImagePath
                 }
                 else
                 {
-                    return _relativeImagePath;
+                    // The `set` accessor below is currently entirely commented out (a
+                    // functional no-op), so _relativeImagePath is never actually assigned by
+                    // this class today. The null-forgiving operator preserves the pre-existing
+                    // behavior of returning whatever _relativeImagePath currently holds
+                    // (including null) rather than introducing a `?? "(none)"` or other
+                    // fallback, which would change the observable return value on this path.
+                    // See docs/features/active/utilitiescs-nullable-svgcontrol/evidence/other/imagepath-judgment-call-decision.md.
+                    return _relativeImagePath!;
                 }
             }
             set
@@ -102,10 +110,10 @@ public string ImagePath
             }
         }
 
-        private ISvgResource _svgResource = null;
+        private ISvgResource? _svgResource = null;
 
         [Editor(typeof(DropDownEditor), typeof(UITypeEditor))]
-        public ISvgResource ResourceName
+        public ISvgResource? ResourceName
         {
             get => _svgResource;
             set
@@ -127,7 +135,12 @@ public ISvgResource ResourceName
                     else
                     {
                         _svgResource = value;
-                        _renderer.Document = SvgRenderer.GetSvgDocument(value.Data);
+                        // value.Data is nullable (ISvgResource.Data); GetSvgDocument's `file`
+                        // parameter is not, preserving the pre-existing behavior of passing
+                        // whatever Data currently holds through unchanged (a genuinely-null
+                        // Data would fail downstream exactly as it did before nullable
+                        // annotations were introduced).
+                        _renderer.Document = SvgRenderer.GetSvgDocument(value.Data!);
                     }
                     NotifyPropertyChanged("ResourceName");
                 }
@@ -165,7 +178,7 @@ public Padding Margin
             set => _renderer.Margin = value;
         }
 
-        public Bitmap Render() => _renderer.Render();
+        public Bitmap? Render() => _renderer.Render();
 
         public bool UseDefaultImage
         {
@@ -210,7 +223,9 @@ public bool SaveRendering
                         // Saves the Image via a FileStream created by the OpenFile method.
                         using FileStream fs = (System.IO.FileStream)saveFileDialog1.OpenFile();
                         {
-                            Image image = Render();
+                            // The outer guard already confirms _renderer.Document != null, so
+                            // Render() cannot return null here; preserves pre-existing behavior.
+                            Image image = Render()!;
                             // Saves the Image in the appropriate ImageFormat based upon the
                             // File type selected in the dialog box.
                             // NOTE that the FilterIndex property is one-based.
@@ -288,7 +303,7 @@ internal void SetDefaultImage()
 
         #region EventHandlers
 
-        public event PropertyChangedEventHandler PropertyChanged;
+        public event PropertyChangedEventHandler? PropertyChanged;
 
         private void Renderer_PropertyChanged(object sender, PropertyChangedEventArgs e)
         {

SVGControl/SvgOptionsConverter.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Globalization;
@@ -20,7 +21,7 @@ Type destinationType
         {
             if (destinationType == typeof(string))
             {
-                SvgImageSelector image = value as SvgImageSelector;
+                SvgImageSelector? image = value as SvgImageSelector;
                 if (image != null)
                 {
                     if (image.AboluteImagePath != null)

SVGControl/SvgOptionsConverter2.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Globalization;
@@ -20,12 +21,12 @@ Type destinationType
         {
             if (destinationType == typeof(string))
             {
-                SvgImageSelector image = value as SvgImageSelector;
+                SvgImageSelector? image = value as SvgImageSelector;
                 if (image != null)
                 {
                     if (image.ResourceName != null)
                     {
-                        string resourceName = image.ResourceName.Name;
+                        string? resourceName = image.ResourceName.Name;
                         string autoSizeCode;
                         switch (image.AutoSize)
                         {

SVGControl/SvgRenderer.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics;
@@ -31,7 +32,7 @@ internal class SvgRenderer : INotifyPropertyChanged
         private static int _resolverInstalled;
 
         [ThreadStatic]
-        private static HashSet<string> _resolving;
+        private static HashSet<string>? _resolving;
 
         static SvgRenderer()
         {
@@ -41,7 +42,7 @@ static SvgRenderer()
             }
         }
 
-        private static System.Reflection.Assembly ResolveByNameAndKey(
+        private static System.Reflection.Assembly? ResolveByNameAndKey(
             object sender,
             ResolveEventArgs args
         )
@@ -103,7 +104,7 @@ ResolveEventArgs args
             return null;
         }
 
-        private static bool PublicKeyTokensEqual(byte[] a, byte[] b)
+        private static bool PublicKeyTokensEqual(byte[]? a, byte[]? b)
         {
             if (a == null || b == null)
             {
@@ -125,7 +126,10 @@ private static bool PublicKeyTokensEqual(byte[] a, byte[] b)
 
         public SvgRenderer(byte[] doc, Size size, AutoSize autoSize)
         {
-            _doc = GetSvgDocument(doc);
+            // GetSvgDocument is annotated SvgDocument? because it swallows load failures and
+            // returns null; this call site preserves pre-existing behavior (assume success and
+            // let a genuine failure surface as an NRE from Draw(), as it always has).
+            _doc = GetSvgDocument(doc)!;
             _original = _doc.Draw().Size;
             _margin = new Padding(0);
             Size = CalcInnerSize(size, _margin);
@@ -134,7 +138,8 @@ public SvgRenderer(byte[] doc, Size size, AutoSize autoSize)
 
         public SvgRenderer(byte[] doc, Size size, Padding margin, AutoSize autoSize)
         {
-            _doc = GetSvgDocument(doc);
+            // See the other byte[]-doc constructor above for the rationale on the `!`.
+            _doc = GetSvgDocument(doc)!;
             _original = _doc.Draw().Size;
             _margin = margin;
             Size = CalcInnerSize(size, _margin);
@@ -171,7 +176,7 @@ public SvgRenderer(Size outer, Padding margin, AutoSize autoSize)
         private Size _outer;
         private Size _original;
         private Padding _margin;
-        private SvgDocument _doc;
+        private SvgDocument? _doc;
         private AutoSize _autoSize;
         private Size _size;
 
@@ -215,15 +220,18 @@ public AutoSize AutoSize
         }
 
         [NotifyParentProperty(true)]
-        public SvgDocument Document
+        public SvgDocument? Document
         {
             get => _doc;
             set
             {
                 _doc = value;
                 if (value != null)
                 {
-                    _original = _doc.Draw().Size;
+                    // _doc == value here (just assigned above); the null-forgiving operator
+                    // reflects the guard on `value` that the compiler cannot see through the
+                    // field assignment.
+                    _original = _doc!.Draw().Size;
                 }
                 NotifyPropertyChanged();
             }
@@ -236,7 +244,7 @@ private Size CalcInnerSize(Size outer, Padding margin)
             return new Size(innerWidth, innerHeight);
         }
 
-        public Bitmap Render()
+        public Bitmap? Render()
         {
             if (_doc == null)
             {
@@ -273,8 +281,10 @@ public Bitmap Render()
 
         private void AddMargins(int widthCurrent, int heightCurrent)
         {
+            // _doc is expected to be set by the time this (currently unreferenced) helper runs;
+            // preserves the pre-existing implicit non-null assumption in this method.
             var group = new SvgGroup();
-            _doc.Children.Add(group);
+            _doc!.Children.Add(group);
             group.Children.Add(
                 new SvgRectangle
                 {
@@ -317,7 +327,7 @@ private Size AdjustSizeProportionately(Size proportions, Size targetSize)
             return proportions;
         }
 
-        public static SvgDocument GetSvgDocument(byte[] file)
+        public static SvgDocument? GetSvgDocument(byte[] file)
         {
             Stream stream = new MemoryStream(file);
             try
@@ -332,7 +342,7 @@ public static SvgDocument GetSvgDocument(byte[] file)
 
         #region EventHandlers
 
-        public event PropertyChangedEventHandler PropertyChanged;
+        public event PropertyChangedEventHandler? PropertyChanged;
 
         private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
         {

SVGControl/SvgResourceConverter.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Globalization;
@@ -32,7 +33,10 @@ Type destinationType
                 else
                 {
                     ISvgResource resource = (ISvgResource)value;
-                    return resource.Name;
+                    // ISvgResource.Name is nullable (SvgResource's parameterless constructor
+                    // never assigns it); this preserves the pre-existing behavior of returning
+                    // whatever Name currently holds, including null, without a new fallback.
+                    return resource.Name!;
                 }
             }
             return "(none)";