Merge pull request #1444 from lukasberanek-tpa/fix/single-allof-with-reference

fix: generate single `allOf` reference to avoid code duplication

Author: ernado

_testdata/positive/allOf.yml

@@ -168,6 +168,21 @@ paths:
       responses:
         '200':
           description: ok
+  "/referencedAllOfNullable":
+    post:
+      operationId: referencedAllOfNullable
+      description: referenced allOf, but requestBody contains nullable refs
+      requestBody:
+        content:
+          application/json:
+            schema:
+              "$ref": "#/components/schemas/ReferencedAllOfNullable"
+          multipart/form-data:
+            schema:
+              "$ref": "#/components/schemas/ReferencedAllOfNullable"
+      responses:
+        '200':
+          description: ok
 components:
   schemas:
     Robot:
@@ -203,3 +218,17 @@ components:
           format: uuid
         location:
           "$ref": "#/components/schemas/Location"
+    ReferencedAllOfNullable:
+      type: object
+      properties:
+        location:
+          "$ref": "#/components/schemas/Location"
+        allOfLocation:
+          type: object
+          allOf:
+            - "$ref": "#/components/schemas/Location"
+        nullableAllOfLocation:
+          type: object
+          nullable: true
+          allOf:
+            - "$ref": "#/components/schemas/Location"

gen/schema_gen_sum.go

@@ -489,6 +489,14 @@ func (g *schemaGen) allOf(name string, schema *jsonschema.Schema) (*ir.Type, err
 		return nil, err
 	}
 
+	// If there is only one schema in allOf, avoid merging to keep the reference.
+	if len(schema.AllOf) == 1 {
+		s := schema.AllOf[0]
+		if s != nil {
+			return g.generate(name, s, false)
+		}
+	}
+
 	mergedSchema, err := mergeNSchemes(schema.AllOf)
 	if err != nil {
 		return nil, err