Avoid zero-length array allocations and storing them in static fields (CA1825) (#10267)

* Avoid zero-length array allocations

* mimic #4027 for XamlMemberInvoker

* Avoid one more unnecessary static pointer holder

Author: h3xds1nz

src/Microsoft.DotNet.Wpf/src/.editorconfig

@@ -92,9 +92,6 @@ dotnet_diagnostic.CA1822.severity = suggestion
 # CA1823: Avoid unused private fields
 dotnet_diagnostic.CA1823.severity = suggestion
 
-# CA1825: Avoid zero-length array allocations
-dotnet_diagnostic.CA1825.severity = suggestion
-
 # CA1834: Use StringBuilder.Append(char) for single character strings
 dotnet_diagnostic.CA1834.severity = suggestion
 

src/Microsoft.DotNet.Wpf/src/PresentationBuildTasks/MS/Internal/MarkupCompiler/MarkupCompiler.cs

@@ -978,11 +978,10 @@ internal void ConnectStyleEvent(XamlClrEventNode xamlClrEventNode)
 
                 // eventSetter = new EventSetter();
                 //
-                CodeExpression[] esParams = {};
                 CodeVariableReferenceExpression cvreES = new CodeVariableReferenceExpression(EVENTSETTER);
                 CodeAssignStatement casES = new CodeAssignStatement(cvreES,
                                                                     new CodeObjectCreateExpression(KnownTypes.Types[(int)KnownElements.EventSetter],
-                                                                                                   esParams));
+                                                                                                   Array.Empty<CodeExpression>()));
 
                 // eventSetter.Event = Button.ClickEvent;
                 //
@@ -3156,9 +3155,8 @@ private CodeVariableReferenceExpression GenerateAppInstance(CodeMemberMethod cmm
             //
             CodeObjectCreateExpression coce;
             CodeVariableReferenceExpression cvre = new CodeVariableReferenceExpression(APPVAR);
-            CodeExpression[] ctorParams = {};
 
-            coce = new CodeObjectCreateExpression(appClassName, ctorParams);
+            coce = new CodeObjectCreateExpression(appClassName, Array.Empty<CodeExpression>());
 
             CodeVariableDeclarationStatement cvds = new CodeVariableDeclarationStatement(appClassName, APPVAR, coce);
 

src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsTable/RowSpanVector.cs

@@ -1,4 +1,4 @@
-// Licensed to the .NET Foundation under one or more agreements.
+// Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
 
@@ -155,7 +155,6 @@ internal void GetNextAvailableRange(out int firstAvailableIndex, out int firstOc
         /// <returns>Array of cells. May be empty</returns>
         internal void GetSpanCells(out TableCell[] cells, out bool isLastRowOfAnySpan)
         {
-            cells = s_noCells;
             isLastRowOfAnySpan = false;
 
             //  iterate the tail of entries (if any) 
@@ -203,10 +202,13 @@ internal void GetSpanCells(out TableCell[] cells, out bool isLastRowOfAnySpan)
 
                 _size = j + 1;
             }
-
-            #if DEBUG
+            else
+            {
+                cells = Array.Empty<TableCell>();
+            }
+#if DEBUG
             _index = -1;
-            #endif // DEBUG
+#endif
         }
 
         #endregion Internal Methods 
@@ -264,8 +266,6 @@ private void InflateCapacity()
         private int _size;                              //  current size of the list
         private int _index;                             //  index used for iteration (GetFirst / GetNext)
         private const int c_defaultCapacity = 8;        //  default capacity
-        private static TableCell[] s_noCells = Array.Empty<TableCell>();  //  empty array RowSpanVector returns to rows that do not 
-                                                        //  have row spanned cells
         #endregion Private Fields 
 
         //------------------------------------------------------

src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/WindowsRuntime/Generated/WinRT/GuidGenerator.cs

@@ -33,7 +33,7 @@ public static string GetSignature(Type type)
                 var sigMethod = helperType.GetMethod("GetGuidSignature", BindingFlags.Static | BindingFlags.Public);
                 if (sigMethod != null)
                 {
-                    return (string)sigMethod.Invoke(null, new Type[] { });
+                    return (string)sigMethod.Invoke(null, Array.Empty<Type>());
                 }
             }
 

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/GridViewAutomationPeer.cs

@@ -146,7 +146,7 @@ IRawElementProviderSimple[] ITableProvider.GetColumnHeaders()
                 return array.ToArray();
             }
 
-            return new IRawElementProviderSimple[0] ;
+            return Array.Empty<IRawElementProviderSimple>();
         }
 
         /// <summary>

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/InkCanvas.cs

@@ -2308,7 +2308,7 @@ internal bool ClearSelectionRaiseSelectionChanging()
             //
             // attempt to clear selection
             //
-            ChangeInkCanvasSelection(new StrokeCollection(), new UIElement[]{});
+            ChangeInkCanvasSelection(new StrokeCollection(), Array.Empty<UIElement>());
 
             return !InkCanvasSelection.HasSelection;
         }
@@ -2324,7 +2324,7 @@ internal void ClearSelection(bool raiseSelectionChangedEvent)
             if ( InkCanvasSelection.HasSelection )
             {
                 // Reset the current selection
-                CoreChangeSelection(new StrokeCollection(), new UIElement[] { }, raiseSelectionChangedEvent);
+                CoreChangeSelection(new StrokeCollection(), Array.Empty<UIElement>(), raiseSelectionChangedEvent);
             }
         }
 
@@ -2509,7 +2509,7 @@ private UIElement[] ValidateSelectedElements(IEnumerable<UIElement> selectedElem
         {
             if (selectedElements == null)
             {
-                return new UIElement[]{};
+                return Array.Empty<UIElement>();
             }
 
             List<UIElement> elements = new List<UIElement>();

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Slider.cs

@@ -947,7 +947,7 @@ private CustomPopupPlacement[] AutoToolTipCustomPlacementCallback(Size popupSize
                     }
 
                 default:
-                    return new CustomPopupPlacement[]{};
+                    return Array.Empty<CustomPopupPlacement>();
             }
         }
 

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/TextSchema.cs

@@ -501,7 +501,7 @@ internal static DependencyProperty[] GetNoninheritableProperties(Type type)
             }
             else if (typeof(LineBreak).IsAssignableFrom(type))
             {
-                return _emptyPropertyList;
+                return Array.Empty<DependencyProperty>();
             }
             else if (typeof(Floater).IsAssignableFrom(type))
             {
@@ -559,7 +559,7 @@ internal static DependencyProperty[] GetNoninheritableProperties(Type type)
             }
 
             Invariant.Assert(false, "We do not expect any unknown elements derived directly from TextElement. Schema must have been checking for that");
-            return _emptyPropertyList; // to make compiler happy
+            return Array.Empty<DependencyProperty>(); // to make compiler happy
         }
 
         // Compares two values for equality
@@ -1201,9 +1201,6 @@ private static bool AreBrushesEqual(Brush brush1, Brush brush2)
                 UIElement.AllowDropProperty,
             };
 
-        // Empty property list
-        private static readonly DependencyProperty[] _emptyPropertyList = new DependencyProperty[] { };
-
         // Structural property list.
         // NB: Existing code depends on these being inheritable properties.
         private static readonly DependencyProperty[] _structuralCharacterProperties = new DependencyProperty[]

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Markup/XamlTypeMapper.cs

@@ -4432,20 +4432,15 @@ internal static string[] GetDefaultAssemblyNames()
         /// </summary>
         internal static NamespaceMapEntry[] GetDefaultNamespaceMaps()
         {
-            return (NamespaceMapEntry[])_defaultNamespaceMapTable.Clone();
+            return Array.Empty<NamespaceMapEntry>();
         }
 
 #endregion Properties
 
 #region Data
 
         // array of our defaultAssemblies.
-        private static readonly string[] _defaultAssemblies = {"WindowsBase", "PresentationCore", "PresentationFramework"};
-
-        // array of namespaceMaps the map an xmlns namespaceURI
-        // to the assembly and urtNamespace to search in when resolving the xml
-
-        private static readonly NamespaceMapEntry[] _defaultNamespaceMapTable = { };
+        private static readonly string[] _defaultAssemblies = { "WindowsBase", "PresentationCore", "PresentationFramework" };
 
 #endregion Data
     }

src/Microsoft.DotNet.Wpf/src/System.Xaml/System/Xaml/Schema/XamlMemberInvoker.cs

@@ -1,4 +1,4 @@
-// Licensed to the .NET Foundation under one or more agreements.
+// Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
 #nullable disable
@@ -12,7 +12,6 @@ public class XamlMemberInvoker
     {
         private static XamlMemberInvoker s_Directive;
         private static XamlMemberInvoker s_Unknown;
-        private static object[] s_emptyObjectArray = Array.Empty<object>();
 
         private XamlMember _member;
         private NullableReference<MethodInfo> _shouldSerializeMethod;
@@ -64,7 +63,7 @@ public virtual object GetValue(object instance)
             }
             else
             {
-                return UnderlyingGetter.Invoke(instance, s_emptyObjectArray);
+                return UnderlyingGetter.Invoke(instance, Array.Empty<object>());
             }
         }