From 4c2d56a6bd214ecc1c5964904bd99b9b901a329d Mon Sep 17 00:00:00 2001
From: glopesdev <glopesdev@users.noreply.github.com>
Date: Fri, 19 Jan 2024 17:49:53 +0000
Subject: [PATCH] Fallback for anonymous array item discriminators

---
 .../DiscriminatorGenerationTests.cs           | 69 +++++++++++++++++++
 Bonsai.Sgen/JsonSchemaExtensions.cs           | 17 +++--
 2 files changed, 80 insertions(+), 6 deletions(-)

diff --git a/Bonsai.Sgen.Tests/DiscriminatorGenerationTests.cs b/Bonsai.Sgen.Tests/DiscriminatorGenerationTests.cs
index 3ffe493..d6e77ea 100644
--- a/Bonsai.Sgen.Tests/DiscriminatorGenerationTests.cs
+++ b/Bonsai.Sgen.Tests/DiscriminatorGenerationTests.cs
@@ -280,5 +280,74 @@ public async Task GenerateFromOneOfDiscriminatorSchemaProperty_SerializerAnnotat
             AssertDiscriminatorAttribute(code, serializerLibraries, "kind");
             CompilerTestHelper.CompileFromSource(code);
         }
+
+        [TestMethod]
+        [DataRow(SerializerLibraries.YamlDotNet)]
+        [DataRow(SerializerLibraries.NewtonsoftJson)]
+        [DataRow(SerializerLibraries.NewtonsoftJson | SerializerLibraries.YamlDotNet)]
+        public async Task GenerateFromArrayItemDiscriminator_EnsureFallbackDiscriminatorBaseTypeName(SerializerLibraries serializerLibraries)
+        {
+            var schema = await JsonSchema.FromJsonAsync(@"
+{
+  ""$schema"": ""http://json-schema.org/draft-04/schema#"",
+  ""type"": ""object"",
+  ""title"": ""Container"",
+  ""properties"": {
+    ""Animals"": {
+      ""type"": ""array"",
+      ""items"": {
+        ""x-abstract"": true,
+        ""discriminator"": {
+          ""propertyName"": ""kind"",
+          ""mapping"": {
+              ""Dog"": ""#/definitions/Dog"",
+              ""Cat"": ""#/definitions/Cat""
+          }
+        },
+        ""oneOf"": [
+          {
+            ""$ref"": ""#/definitions/Dog""
+          },
+          {
+            ""$ref"": ""#/definitions/Cat""
+          },
+          {
+            ""type"": ""null""
+          }
+        ]
+      }
+    }
+  },
+  ""definitions"": {
+    ""Dog"": {
+      ""type"": ""object"",
+      ""properties"": {
+        ""kind"": {
+          ""enum"": [ ""Dog"" ]
+        }
+      },
+      ""required"": [ ""kind"" ]
+    },
+    ""Cat"": {
+      ""type"": ""object"",
+      ""properties"": {
+        ""kind"": {
+          ""enum"": [ ""Cat"" ]
+        }
+      },
+      ""required"": [ ""kind"" ]
+    }
+  }
+}
+");
+            var generator = TestHelper.CreateGenerator(schema, serializerLibraries);
+            var code = generator.GenerateFile();
+            Assert.IsTrue(code.Contains("class Dog : Anonymous"), "Derived types do not inherit from base type.");
+            Assert.IsTrue(!code.Contains("public enum DogKind"), "Discriminator property is repeated in derived types.");
+            Assert.IsTrue(code.Contains("List<Anonymous> Animal"), "Container element type does not match base type.");
+            Assert.IsTrue(code.Contains("[JsonInheritanceAttribute(\"Dog\", typeof(Dog))]"));
+            AssertDiscriminatorAttribute(code, serializerLibraries, "kind");
+            CompilerTestHelper.CompileFromSource(code);
+        }
     }
 }
diff --git a/Bonsai.Sgen/JsonSchemaExtensions.cs b/Bonsai.Sgen/JsonSchemaExtensions.cs
index 2bcf3d8..3685a55 100644
--- a/Bonsai.Sgen/JsonSchemaExtensions.cs
+++ b/Bonsai.Sgen/JsonSchemaExtensions.cs
@@ -26,14 +26,19 @@ protected override JsonSchema VisitSchema(JsonSchema schema, string path, string
             {
                 if (schema.DiscriminatorObject != null)
                 {
-                    if (schema is JsonSchemaProperty schemaProperty)
+                    if (schema is JsonSchemaProperty || schema.ParentSchema?.Item == schema)
                     {
+                        if (string.IsNullOrEmpty(typeNameHint))
+                        {
+                            typeNameHint = "Anonymous";
+                        }
+
                         if (!RootObject.Definitions.ContainsKey(typeNameHint))
                         {
                             var discriminatorSchema = new JsonSchema();
-                            discriminatorSchema.DiscriminatorObject = schemaProperty.DiscriminatorObject;
-                            discriminatorSchema.IsAbstract = schemaProperty.IsAbstract;
-                            foreach (var derivedSchema in schemaProperty.OneOf)
+                            discriminatorSchema.DiscriminatorObject = schema.DiscriminatorObject;
+                            discriminatorSchema.IsAbstract = schema.IsAbstract;
+                            foreach (var derivedSchema in schema.OneOf)
                             {
                                 if (derivedSchema.IsNullable(SchemaType.JsonSchema))
                                 {
@@ -45,8 +50,8 @@ protected override JsonSchema VisitSchema(JsonSchema schema, string path, string
                             RootObject.Definitions.Add(typeNameHint, discriminatorSchema);
                         }
 
-                        schemaProperty.DiscriminatorObject = null;
-                        schemaProperty.IsAbstract = false;
+                        schema.DiscriminatorObject = null;
+                        schema.IsAbstract = false;
                         return schema;
                     }