Models Builder: Make Models Builder better at not performing "rude edits" (#20394)

Make Models Builder better at not performing rude edits

Author: kjac

src/Umbraco.Core/Configuration/Models/ModelsBuilderSettings.cs

@@ -17,6 +17,7 @@ public class ModelsBuilderSettings
     internal const bool StaticAcceptUnsafeModelsDirectory = false;
     internal const int StaticDebugLevel = 0;
     internal const bool StaticIncludeVersionNumberInGeneratedModels = true;
+    internal const bool StaticGenerateVirtualProperties = true;
     private bool _flagOutOfDateModels = true;
 
     /// <summary>
@@ -77,4 +78,13 @@ public bool FlagOutOfDateModels
     /// </remarks>
     [DefaultValue(StaticIncludeVersionNumberInGeneratedModels)]
     public bool IncludeVersionNumberInGeneratedModels { get; set; } = StaticIncludeVersionNumberInGeneratedModels;
+
+    /// <summary>
+    ///     Gets or sets a value indicating whether to mark all properties in the generated models as virtual.
+    /// </summary>
+    /// <remarks>
+    ///     Virtual properties will not work with Hot Reload when running dotnet watch.
+    /// </remarks>
+    [DefaultValue(StaticGenerateVirtualProperties)]
+    public bool GenerateVirtualProperties { get; set; } = StaticGenerateVirtualProperties;
 }

src/Umbraco.Infrastructure/ModelsBuilder/Building/ModelsGenerator.cs

@@ -31,21 +31,37 @@ public void GenerateModels()
             Directory.CreateDirectory(modelsDirectory);
         }
 
-        foreach (var file in Directory.GetFiles(modelsDirectory, "*.generated.cs"))
-        {
-            File.Delete(file);
-        }
-
         IList<TypeModel> typeModels = _umbracoService.GetAllTypes();
 
         var builder = new TextBuilder(_config, typeModels);
 
+        var generatedFiles = new List<string>();
         foreach (TypeModel typeModel in builder.GetModelsToGenerate())
         {
             var sb = new StringBuilder();
             builder.Generate(sb, typeModel);
             var filename = Path.Combine(modelsDirectory, typeModel.ClrName + ".generated.cs");
-            File.WriteAllText(filename, sb.ToString());
+            generatedFiles.Add(filename);
+
+            var code = sb.ToString();
+
+            // leave the file alone if its contents is identical to the generated model
+            if (File.Exists(filename) && File.ReadAllText(filename).Equals(code))
+            {
+                continue;
+            }
+
+            // overwrite the file
+            File.WriteAllText(filename, code);
+        }
+
+        // clean up old/leftover generated files
+        foreach (var file in Directory.GetFiles(modelsDirectory, "*.generated.cs"))
+        {
+            if (generatedFiles.InvariantContains(file) is false)
+            {
+                File.Delete(file);
+            }
         }
 
         // the idea was to calculate the current hash and to add it as an extra file to the compilation,

src/Umbraco.Infrastructure/ModelsBuilder/Building/TextBuilder.cs

@@ -384,7 +384,11 @@ private void WriteMixinProperty(StringBuilder sb, PropertyModel property, string
 
         sb.AppendFormat("\t\t[ImplementPropertyType(\"{0}\")]\n", property.Alias);
 
-        sb.Append("\t\tpublic virtual ");
+        sb.Append("\t\tpublic ");
+        if (Config.GenerateVirtualProperties)
+        {
+            sb.Append("virtual ");
+        }
         WriteClrType(sb, property.ClrTypeName);
 
         sb.AppendFormat(
@@ -460,15 +464,23 @@ private void WriteProperty(StringBuilder sb, TypeModel type, PropertyModel prope
 
         if (mixinStatic)
         {
-            sb.Append("\t\tpublic virtual ");
+            sb.Append("\t\tpublic ");
+            if (Config.GenerateVirtualProperties)
+            {
+                sb.Append("virtual ");
+            }
             WriteClrType(sb, property.ClrTypeName);
             sb.AppendFormat(
                 " {0} => {1}(this, _publishedValueFallback);\n",
                 property.ClrName, MixinStaticGetterName(property.ClrName));
         }
         else
         {
-            sb.Append("\t\tpublic virtual ");
+            sb.Append("\t\tpublic ");
+            if (Config.GenerateVirtualProperties)
+            {
+                sb.Append("virtual ");
+            }
             WriteClrType(sb, property.ClrTypeName);
             sb.AppendFormat(
                 " {0} => this.Value",