Fix generation when [DefaultValue]'s type differs

Fix SwaggerGeneratorException if the type of a `[DefaultValue]` does not match the type of the property when using System.Text.Json for serialization. Resolves domaindrivendev#2885.
martincostello · May 16, 2024 · 4d48475 · 4d48475
1 parent ecce973
commit 4d48475
Show file tree

Hide file tree

Showing 4 changed files with 23 additions and 1 deletion.
diff --git a/src/Swashbuckle.AspNetCore.SwaggerGen/SchemaGenerator/SchemaGenerator.cs b/src/Swashbuckle.AspNetCore.SwaggerGen/SchemaGenerator/SchemaGenerator.cs
@@ -80,7 +80,24 @@ private OpenApiSchema GenerateSchemaForMember(
                 var defaultValueAttribute = customAttributes.OfType<DefaultValueAttribute>().FirstOrDefault();
                 if (defaultValueAttribute != null)
                 {
-                    var defaultAsJson = dataContract.JsonConverter(defaultValueAttribute.Value);
+                    var defaultValue = defaultValueAttribute.Value;
+
+                    // If the types do not match (e.g. a default which is an integer is specified for a double),
+                    // attempt to coerce the default value to the correct type so that it can be serialized correctly.
+                    // See https://github.com/domaindrivendev/Swashbuckle.AspNetCore/issues/2885.
+                    if (defaultValue?.GetType() != modelType)
+                    {
+                        try
+                        {
+                            defaultValue = Convert.ChangeType(defaultValue, modelType);
+                        }
+                        catch (Exception)
+                        {
+                            // Conversion failed, use the original default value anyway
+                        }
+                    }
+
+                    var defaultAsJson = dataContract.JsonConverter(defaultValue);
                     schema.Default = OpenApiAnyFactory.CreateFromJson(defaultAsJson);
                 }
 

diff --git a/.../Swashbuckle.AspNetCore.Newtonsoft.Test/SchemaGenerator/NewtonsoftSchemaGeneratorTests.cs b/.../Swashbuckle.AspNetCore.Newtonsoft.Test/SchemaGenerator/NewtonsoftSchemaGeneratorTests.cs
@@ -269,6 +269,7 @@ public void GenerateSchema_SetsNullableFlag_IfPropertyIsReferenceOrNullableType(
         [InlineData(typeof(TypeWithDefaultAttributes), nameof(TypeWithDefaultAttributes.LongWithDefault), "9223372036854775807")]
         [InlineData(typeof(TypeWithDefaultAttributes), nameof(TypeWithDefaultAttributes.FloatWithDefault), "3.4028235E+38")]
         [InlineData(typeof(TypeWithDefaultAttributes), nameof(TypeWithDefaultAttributes.DoubleWithDefault), "1.7976931348623157E+308")]
+        [InlineData(typeof(TypeWithDefaultAttributes), nameof(TypeWithDefaultAttributes.DoubleWithDefaultOfDifferentType), "1")]
         [InlineData(typeof(TypeWithDefaultAttributes), nameof(TypeWithDefaultAttributes.StringWithDefault), "\"foobar\"")]
         [InlineData(typeof(TypeWithDefaultAttributes), nameof(TypeWithDefaultAttributes.IntArrayWithDefault), "[\n  1,\n  2,\n  3\n]")]
         [InlineData(typeof(TypeWithDefaultAttributes), nameof(TypeWithDefaultAttributes.StringArrayWithDefault), "[\n  \"foo\",\n  \"bar\"\n]")]

diff --git a/...shbuckle.AspNetCore.SwaggerGen.Test/SchemaGenerator/JsonSerializerSchemaGeneratorTests.cs b/...shbuckle.AspNetCore.SwaggerGen.Test/SchemaGenerator/JsonSerializerSchemaGeneratorTests.cs
@@ -292,6 +292,7 @@ public void GenerateSchema_SetsNullableFlag_IfPropertyIsReferenceOrNullableType(
         [InlineData(typeof(TypeWithDefaultAttributes), nameof(TypeWithDefaultAttributes.LongWithDefault), "9223372036854775807")]
         [InlineData(typeof(TypeWithDefaultAttributes), nameof(TypeWithDefaultAttributes.FloatWithDefault), "3.4028235E+38")]
         [InlineData(typeof(TypeWithDefaultAttributes), nameof(TypeWithDefaultAttributes.DoubleWithDefault), "1.7976931348623157E+308")]
+        [InlineData(typeof(TypeWithDefaultAttributes), nameof(TypeWithDefaultAttributes.DoubleWithDefaultOfDifferentType), "1")]
         [InlineData(typeof(TypeWithDefaultAttributes), nameof(TypeWithDefaultAttributes.StringWithDefault), "\"foobar\"")]
         [InlineData(typeof(TypeWithDefaultAttributes), nameof(TypeWithDefaultAttributes.IntArrayWithDefault), "[\n  1,\n  2,\n  3\n]")]
         [InlineData(typeof(TypeWithDefaultAttributes), nameof(TypeWithDefaultAttributes.StringArrayWithDefault), "[\n  \"foo\",\n  \"bar\"\n]")]

diff --git a/test/Swashbuckle.AspNetCore.TestSupport/Fixtures/TypeWithDefaultAttributes.cs b/test/Swashbuckle.AspNetCore.TestSupport/Fixtures/TypeWithDefaultAttributes.cs
@@ -19,6 +19,9 @@ public class TypeWithDefaultAttributes
         [DefaultValue(double.MaxValue)]
         public double DoubleWithDefault { get; set; }
 
+        [DefaultValue(1)] // Repro for https://github.com/domaindrivendev/Swashbuckle.AspNetCore/issues/2885
+        public double DoubleWithDefaultOfDifferentType { get; set; }
+
         [DefaultValue("foobar")]
         public string StringWithDefault { get; set; }