Fix #1166 Exception with Code generator when an attribute name has no alfanumeric characters

src/HassModel/NetDaemon.HassModel.CodeGenerator/CodeGeneration/ServiceArguments.cs

@@ -62,12 +62,15 @@ public string GetNewServiceArgumentsTypeExpression()
 
         return $"new {TypeName} {{  { string.Join(", ", propertyInitializers) }  }}";
     }
-
+
+    /// <summary>
+    /// If the identifier matches a C# keyword we need to prefix it with a @
+    /// </summary>
     private static string EscapeIfRequired(string name)
     {
         var match = SyntaxFacts.GetKeywordKind(name) != SyntaxKind.None ||
                     SyntaxFacts.GetContextualKeywordKind(name) != SyntaxKind.None;
 
         return match ? "@" + name : name;
     }
-}
+}

src/HassModel/NetDaemon.HassModel.CodeGenerator/Extensions/StringExtensions.cs

@@ -22,12 +22,12 @@ public static string ToValidCSharpIdentifier(this string name)
 
         name = Regex.Replace(name, "[^a-zA-Z0-9_]+", "", RegexOptions.Compiled);
 
-        if (char.IsAsciiDigit(name[0]))
+        if (name.Length == 0 || char.IsAsciiDigit(name[0]))
             name = "_" + name;
 
         return name;
     }
-        
+
     public static string ToPascalCase(this string str)
     {
         var build = new StringBuilder(str.Length);
@@ -55,4 +55,4 @@ public static string ToCamelCase(this string str)
 
         return char.ToLowerInvariant(camelCaseStr[0]) + camelCaseStr[1..];
     }
-}
+}

src/HassModel/NetDaemon.HassModel.Tests/CodeGenerator/CodeGeneratorTest.cs

@@ -1,4 +1,5 @@
-using Microsoft.CodeAnalysis.CSharp.Syntax;
+using System.Text.Json;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
 using NetDaemon.Client.HomeAssistant.Model;
 using NetDaemon.HassModel.CodeGenerator;
 using NetDaemon.HassModel.CodeGenerator.Model;
@@ -176,6 +177,38 @@ public void Run(IHaContext ha)
         CodeGenTestHelper.AssertCodeCompiles(generatedCode.ToString(), appCode);
     }
 
+    [Fact]
+    public void TestAttributeWithoutValidCSharpChars()
+    {
+        // Numeric entities should be generated for input_numbers and sensors with a unit_of_measurement attribute
+        var entityStates = new HassState[] {
+            new()
+            {
+                EntityId = "InputNumber.TargetTemperature",
+                AttributesJson = JsonSerializer.Deserialize<JsonElement>("""{"----" :  "bogus", "&^%" :  "more bugus"} """),
+            }
+        };
+        var generatedCode = CodeGenTestHelper.GenerateCompilationUnit(_settings, entityStates, Array.Empty<HassServiceDomain>());
+        var appCode = """
+                        using NetDaemon.HassModel.Entities;
+                        using NetDaemon.HassModel;
+                        using RootNameSpace;
+                        using System.Collections.Generic;
+
+                        public class Root
+                        {
+                            public void Run(Entities entities)
+                            {
+                                InputNumberEntity targetTempEntity = entities.InputNumber.TargetTemperature;
+                                string? bogus1 = targetTempEntity.Attributes?.__0;
+                                string? bogus2 =  targetTempEntity.Attributes?.__1;
+                             }
+                        }
+                        """;
+        CodeGenTestHelper.AssertCodeCompiles(generatedCode.ToString(), appCode);
+    }
+
+
     [Fact]
     public void TestNumberExtensionMethodGeneration()
     {