Make JSON support required properties

src/libraries/System.Text.Json/src/System/Text/Json/JsonHelpers.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Buffers;
+using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
@@ -147,5 +148,19 @@ public static void ValidateInt32MaxArrayLength(uint length)
                 ThrowHelper.ThrowOutOfMemoryException(length);
             }
         }
+
+        public static bool AllBitsEqual(this BitArray bitArray, bool value)
+        {
+            // Optimize this when https://github.com/dotnet/runtime/issues/72999 is fixed
+            for (int i = 0; i < bitArray.Count; i++)
+            {
+                if (bitArray[i] != value)
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
     }
 }

src/libraries/System.Text.Json/src/System/Text/Json/Serialization/ReadStackFrame.cs

@@ -118,7 +118,7 @@ public void MarkRequiredPropertyAsRead(JsonPropertyInfo propertyInfo)
             if (propertyInfo.IsRequired)
             {
                 Debug.Assert(RequiredPropertiesLeft != null);
-                RequiredPropertiesLeft.Set(propertyInfo.RequiredPropertyIndex, false);
+                RequiredPropertiesLeft[propertyInfo.RequiredPropertyIndex] = false;
             }
         }
 
@@ -140,13 +140,9 @@ internal void ValidateAllRequiredPropertiesAreRead(JsonTypeInfo typeInfo)
             {
                 Debug.Assert(RequiredPropertiesLeft != null);
 
-                // Optimize this when https://github.com/dotnet/runtime/issues/72999 is fixed
-                for (int i = 0; i < RequiredPropertiesLeft.Count; i++)
+                if (!RequiredPropertiesLeft.AllBitsEqual(false))
                 {
-                    if (RequiredPropertiesLeft[i])
-                    {
-                        ThrowHelper.ThrowJsonException_JsonRequiredPropertyMissing(typeInfo, RequiredPropertiesLeft);
-                    }
+                    ThrowHelper.ThrowJsonException_JsonRequiredPropertyMissing(typeInfo, RequiredPropertiesLeft);
                 }
             }
         }

src/libraries/System.Text.Json/src/System/Text/Json/ThrowHelper.Serialization.cs

@@ -223,38 +223,22 @@ public static void ThrowJsonException_JsonRequiredPropertyMissing(JsonTypeInfo p
 
             Debug.Assert(parent.PropertyCache != null);
 
-            int propertyIdx = 0;
-
-            for (int requiredPropertyIdx = 0; requiredPropertyIdx < missingJsonProperties.Length; requiredPropertyIdx++)
+            for (int propertyIdx = 0; propertyIdx < parent.PropertyCache.List.Count; propertyIdx++)
             {
-                if (!missingJsonProperties[requiredPropertyIdx])
-                {
-                    continue;
-                }
+                JsonPropertyInfo property = parent.PropertyCache.List[propertyIdx].Value;
 
-                JsonPropertyInfo? missingProperty = null;
-
-                // requiredPropertyIdx indices occur consecutively so we can resume iteration
-                for (; propertyIdx < parent.PropertyCache.List.Count; propertyIdx++)
+                if (!property.IsRequired || !missingJsonProperties[property.RequiredPropertyIndex])
                 {
-                    JsonPropertyInfo maybeMissingProperty = parent.PropertyCache.List[propertyIdx].Value;
-                    if (maybeMissingProperty.IsRequired && maybeMissingProperty.RequiredPropertyIndex == requiredPropertyIdx)
-                    {
-                        missingProperty = maybeMissingProperty;
-                        break;
-                    }
+                    continue;
                 }
 
-                Debug.Assert(propertyIdx != parent.PropertyCache.List.Count);
-                Debug.Assert(missingProperty != null);
-
                 if (!first)
                 {
                     listOfMissingPropertiesBuilder.Append(CultureInfo.CurrentUICulture.TextInfo.ListSeparator);
                     listOfMissingPropertiesBuilder.Append(' ');
                 }
 
-                listOfMissingPropertiesBuilder.Append(missingProperty.Name);
+                listOfMissingPropertiesBuilder.Append(property.Name);
                 first = false;
             }