Don't output enum descriptions if all empty (#1854)

Author: lahma

src/NJsonSchema.Tests/Generation/EnumTests.cs

@@ -190,6 +190,29 @@ public async Task When_enum_has_description_attributes_then_descriptions_are_inc
             await VerifyHelper.Verify(json);
         }
 
+        [Fact]
+        public async Task When_enum_has_no_description_attributes_then_descriptions_are_not_included_in_schema()
+        {
+            // Arrange
+
+            // Act
+            var schema = NewtonsoftJsonSchemaGenerator.FromType<EnumWithFlags>(new NewtonsoftJsonSchemaGeneratorSettings
+            {
+                SerializerSettings =
+                {
+                    Converters = { new StringEnumConverter() }
+                }
+            });
+            var json = schema.ToJson();
+
+            // Assert
+            Assert.Empty(schema.EnumerationDescriptions);
+
+            // Verify the JSON output does not contain the x-enumDescriptions property
+            await VerifyHelper.Verify(json);
+        }
+
+
         [Fact]
         public async Task When_schema_has_x_enum_names_then_backward_compatibility_works()
         {

src/NJsonSchema.Tests/Generation/Snapshots/EnumTests.When_enum_has_no_description_attributes_then_descriptions_are_not_included_in_schema.verified.txt

@@ -0,0 +1,17 @@
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "title": "EnumWithFlags",
+  "type": "string",
+  "description": "",
+  "x-enumFlags": true,
+  "x-enumNames": [
+    "Foo",
+    "Bar",
+    "Baz"
+  ],
+  "enum": [
+    "Foo",
+    "Bar",
+    "Baz"
+  ]
+}

src/NJsonSchema/Generation/JsonSchemaGenerator.cs

@@ -702,6 +702,7 @@ protected virtual void GenerateEnum(JsonSchema schema, JsonTypeDescription typeD
             schema.EnumerationDescriptions.Clear();
             schema.IsFlagEnumerable = contextualType.IsAttributeDefined<FlagsAttribute>(true);
 
+            var allDescriptionsEmpty = true;
             Func<object, string?>? enumValueConverter = null;
             var underlyingType = Enum.GetUnderlyingType(contextualType.Type);
             foreach (var enumName in Enum.GetNames(contextualType.Type))
@@ -739,6 +740,13 @@ protected virtual void GenerateEnum(JsonSchema schema, JsonTypeDescription typeD
 
                 schema.EnumerationNames.Add(enumName);
                 schema.EnumerationDescriptions.Add(enumDescription);
+                allDescriptionsEmpty &= string.IsNullOrWhiteSpace(enumDescription);
+            }
+
+            if (allDescriptionsEmpty)
+            {
+                // don't output empty descriptions
+                schema.EnumerationDescriptions.Clear();
             }
 
             if (typeDescription.Type == JsonObjectType.Integer && Settings.GenerateEnumMappingDescription)