Address PR feedback: consolidate helpers and fix formatting

- Revert changes to .gitignore
- Fix formatting issues in test file (remove extra blank lines)
- Make HasEffectiveDefaultValue and GetEffectiveDefaultValue internal in AIJsonUtilities
- Remove duplicate helper methods from AIFunctionFactory and use the ones from AIJsonUtilities

Co-authored-by: stephentoub <2642209+stephentoub@users.noreply.github.com>

Author: Copilot

.gitignore

@@ -319,4 +319,3 @@ BenchmarkDotNet.artifacts/
 
 # VERIFY
 !**/*.verified/**
-/.nuget/

src/Libraries/Microsoft.Extensions.AI.Abstractions/Functions/AIFunctionFactory.cs

@@ -803,27 +803,6 @@ static bool IsAsyncMethod(MethodInfo method)
             }
         }
 
-        /// <summary>
-        /// Checks if a parameter has an effective default value, either through C# default value syntax or DefaultValueAttribute.
-        /// </summary>
-        private static bool HasEffectiveDefaultValue(ParameterInfo parameter) =>
-            parameter.HasDefaultValue || parameter.GetCustomAttribute<DefaultValueAttribute>(inherit: true) is not null;
-
-        /// <summary>
-        /// Gets the effective default value for a parameter, checking both C# default value and DefaultValueAttribute.
-        /// </summary>
-        private static object? GetEffectiveDefaultValue(ParameterInfo parameter)
-        {
-            // First check for DefaultValueAttribute
-            if (parameter.GetCustomAttribute<DefaultValueAttribute>(inherit: true) is { } attr)
-            {
-                return attr.Value;
-            }
-
-            // Fall back to the parameter's declared default value
-            return parameter.DefaultValue;
-        }
-
         /// <summary>
         /// Gets a delegate for handling the marshaling of a parameter.
         /// </summary>
@@ -868,7 +847,7 @@ private static bool HasEffectiveDefaultValue(ParameterInfo parameter) =>
                 return (arguments, _) =>
                 {
                     IServiceProvider? services = arguments.Services;
-                    if (!HasEffectiveDefaultValue(parameter) && services is null)
+                    if (!AIJsonUtilities.HasEffectiveDefaultValue(parameter) && services is null)
                     {
                         ThrowNullServices(parameter.Name);
                     }
@@ -928,13 +907,13 @@ private static bool HasEffectiveDefaultValue(ParameterInfo parameter) =>
                 }
 
                 // If the parameter is required and there's no argument specified for it, throw.
-                if (!HasEffectiveDefaultValue(parameter))
+                if (!AIJsonUtilities.HasEffectiveDefaultValue(parameter))
                 {
                     Throw.ArgumentException(nameof(arguments), $"The arguments dictionary is missing a value for the required parameter '{parameter.Name}'.");
                 }
 
                 // Otherwise, use the optional parameter's default value.
-                return GetEffectiveDefaultValue(parameter);
+                return AIJsonUtilities.GetEffectiveDefaultValue(parameter);
             };
 
             // Throws an ArgumentNullException indicating that AIFunctionArguments.Services must be provided.

src/Libraries/Microsoft.Extensions.AI.Abstractions/Utilities/AIJsonUtilities.Schema.Create.cs

@@ -764,13 +764,13 @@ private static JsonElement ParseJsonElement(ReadOnlySpan<byte> utf8Json)
     /// <summary>
     /// Checks if a parameter has an effective default value, either through C# default value syntax or DefaultValueAttribute.
     /// </summary>
-    private static bool HasEffectiveDefaultValue(ParameterInfo parameterInfo) =>
+    internal static bool HasEffectiveDefaultValue(ParameterInfo parameterInfo) =>
         parameterInfo.HasDefaultValue || parameterInfo.GetCustomAttribute<DefaultValueAttribute>(inherit: true) is not null;
 
     /// <summary>
     /// Gets the effective default value for a parameter, checking both C# default value and DefaultValueAttribute.
     /// </summary>
-    private static object? GetEffectiveDefaultValue(ParameterInfo parameterInfo)
+    internal static object? GetEffectiveDefaultValue(ParameterInfo parameterInfo)
     {
         // First check for DefaultValueAttribute
         if (parameterInfo.GetCustomAttribute<DefaultValueAttribute>(inherit: true) is { } attr)

test/Libraries/Microsoft.Extensions.AI.Tests/Functions/AIFunctionFactoryTest.cs

@@ -66,43 +66,43 @@ public async Task Parameters_DefaultValueAttributeIsRespected_Async()
     {
         // Test with null default value
         AIFunction funcNull = AIFunctionFactory.Create(([DefaultValue(null)] string? s) => s ?? "was null");
-        
+
         // Schema should not list 's' as required and should have default value
         string schema = funcNull.JsonSchema.ToString();
         Assert.Contains("\"s\"", schema);
         Assert.DoesNotContain("\"required\"", schema);
         Assert.Contains("\"default\":null", schema);
-        
+
         // Should be invocable without providing the parameter
         AssertExtensions.EqualFunctionCallResults("was null", await funcNull.InvokeAsync());
-        
+
         // Should be overridable
         AssertExtensions.EqualFunctionCallResults("hello", await funcNull.InvokeAsync(new() { ["s"] = "hello" }));
-        
+
         // Test with non-null default value
         AIFunction funcValue = AIFunctionFactory.Create(([DefaultValue("default")] string s) => s);
         schema = funcValue.JsonSchema.ToString();
         Assert.DoesNotContain("\"required\"", schema);
         Assert.Contains("\"default\":\"default\"", schema);
-        
+
         AssertExtensions.EqualFunctionCallResults("default", await funcValue.InvokeAsync());
         AssertExtensions.EqualFunctionCallResults("custom", await funcValue.InvokeAsync(new() { ["s"] = "custom" }));
-        
+
         // Test with int default value
         AIFunction funcInt = AIFunctionFactory.Create(([DefaultValue(42)] int x) => x * 2);
         schema = funcInt.JsonSchema.ToString();
         Assert.DoesNotContain("\"required\"", schema);
         Assert.Contains("\"default\":42", schema);
-        
+
         AssertExtensions.EqualFunctionCallResults(84, await funcInt.InvokeAsync());
         AssertExtensions.EqualFunctionCallResults(10, await funcInt.InvokeAsync(new() { ["x"] = 5 }));
-        
+
         // Test that DefaultValue attribute takes precedence over C# default value
         AIFunction funcBoth = AIFunctionFactory.Create(([DefaultValue(100)] int y = 50) => y);
         schema = funcBoth.JsonSchema.ToString();
         Assert.DoesNotContain("\"required\"", schema);
         Assert.Contains("\"default\":100", schema); // DefaultValue should take precedence
-        
+
         AssertExtensions.EqualFunctionCallResults(100, await funcBoth.InvokeAsync()); // Should use DefaultValue, not C# default
     }