[inline model resolver] Add support for inline enum refactoring (#16033)

* add support for inline enum refactoring

* minor update

* add tests

docs/customization.md

@@ -455,6 +455,7 @@ Note: Only arrayItemSuffix, mapItemSuffix are supported at the moment.
 There are 2 special values:
 - `SKIP_SCHEMA_REUSE=true` is a special value to skip reusing inline schemas.
 - `REFACTOR_ALLOF_INLINE_SCHEMAS=true` will restore the 6.x (or below) behaviour to refactor allOf inline schemas into $ref. (v7.0.0 will skip the refactoring of these allOf inline schmeas by default)
+- `RESOLVE_INLINE_ENUMS=true` will refactor inline enum definitions into $ref
 
 ## OpenAPI Normalizer
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/InlineModelResolver.java

@@ -81,11 +81,13 @@ public class InlineModelResolver {
         }
 
         if (this.inlineSchemaNameDefaults.containsKey("REFACTOR_ALLOF_INLINE_SCHEMAS")) {
-            if (Boolean.valueOf(this.inlineSchemaNameDefaults.get("REFACTOR_ALLOF_INLINE_SCHEMAS"))) {
+            this.refactorAllOfInlineSchemas = Boolean.valueOf(this.inlineSchemaNameDefaults.get("REFACTOR_ALLOF_INLINE_SCHEMAS"));
-                this.refactorAllOfInlineSchemas = true;
+        } else {
-            } else { // set to false
+            // not set so default to null;
-                this.refactorAllOfInlineSchemas = false;
+        }
-            }
+
+        if (this.inlineSchemaNameDefaults.containsKey("RESOLVE_INLINE_ENUMS")) {
+            this.resolveInlineEnums = Boolean.valueOf(this.inlineSchemaNameDefaults.get("RESOLVE_INLINE_ENUMS"));
         } else {
             // not set so default to null;
         }

modules/openapi-generator/src/test/java/org/openapitools/codegen/InlineModelResolverTest.java

@@ -23,6 +23,7 @@ import io.swagger.v3.oas.models.OpenAPI;
 import io.swagger.v3.oas.models.Operation;
 import io.swagger.v3.oas.models.PathItem;
 import io.swagger.v3.oas.models.media.*;
+import io.swagger.v3.oas.models.parameters.Parameter;
 import io.swagger.v3.oas.models.parameters.RequestBody;
 import io.swagger.v3.oas.models.responses.ApiResponse;
 import io.swagger.v3.oas.models.responses.ApiResponses;
@@ -1129,4 +1130,45 @@ public class InlineModelResolverTest {
         assertTrue((Schema) schema.getAnyOf().get(0) instanceof StringSchema);
         assertTrue((Schema) schema.getAnyOf().get(1) instanceof IntegerSchema);
     }
+
+    @Test
+    public void resolveOperationInlineEnum() {
+        OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/inline_model_resolver.yaml");
+        Parameter parameter = openAPI.getPaths().get("/resolve_parameter_inline_enum").getGet().getParameters().get(0);
+        assertNull(((ArraySchema) parameter.getSchema()).getItems().get$ref() );
+
+        InlineModelResolver resolver = new InlineModelResolver();
+        Map<String, String> inlineSchemaNameDefaults = new HashMap<>();
+        inlineSchemaNameDefaults.put("RESOLVE_INLINE_ENUMS", "true");
+        resolver.setInlineSchemaNameDefaults(inlineSchemaNameDefaults);
+        resolver.flatten(openAPI);
+
+        Parameter parameter2 = openAPI.getPaths().get("/resolve_parameter_inline_enum").getGet().getParameters().get(0);
+        assertEquals("#/components/schemas/resolveParameterInlineEnum_status_inline_enum_parameter_inner",
+                ((ArraySchema) parameter2.getSchema()).getItems().get$ref() );
+
+    }
+
+    @Test
+    public void resolveOperationInlineEnumFormParameters() {
+        OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/inline_model_resolver.yaml");
+        Schema requestBody = openAPI.getPaths().get("/resolve_parameter_inline_enum_form_parameters").getPost().getRequestBody().getContent().get("application/x-www-form-urlencoded").getSchema();
+        assertNull(requestBody.get$ref());
+
+        InlineModelResolver resolver = new InlineModelResolver();
+        Map<String, String> inlineSchemaNameDefaults = new HashMap<>();
+        inlineSchemaNameDefaults.put("RESOLVE_INLINE_ENUMS", "true");
+        resolver.setInlineSchemaNameDefaults(inlineSchemaNameDefaults);
+        resolver.flatten(openAPI);
+
+        Schema requestBody2 = openAPI.getPaths().get("/resolve_parameter_inline_enum_form_parameters").getPost().getRequestBody().getContent().get("application/x-www-form-urlencoded").getSchema();
+        assertEquals("#/components/schemas/resolve_parameter_inline_enum_form_parameters_request", requestBody2.get$ref());
+
+        Schema inlineFormParaemter = (Schema) openAPI.getComponents().getSchemas().get("resolve_parameter_inline_enum_form_parameters_request");
+        assertNotNull(inlineFormParaemter);
+        assertEquals(2, inlineFormParaemter.getProperties().size());
+        assertEquals("#/components/schemas/resolve_parameter_inline_enum_form_parameters_request_enum_form_string",
+                ((Schema) inlineFormParaemter.getProperties().get("enum_form_string")).get$ref());
+
+    }
 }

modules/openapi-generator/src/test/resources/3_0/inline_model_resolver.yaml

@@ -7,6 +7,58 @@ info:
 servers:
   - url: http://api.example.xyz/v1
 paths:
+  /resolve_parameter_inline_enum:
+    get:
+      parameters:
+        - name: status_inline_enum
+          in: query
+          description: Status values that need to be considered for filter
+          required: true
+          style: form
+          explode: false
+          deprecated: true
+          schema:
+            type: array
+            items:
+              type: string
+              enum:
+                - available
+                - pending
+                - sold
+              default: available
+      operationId: resolveParameterInlineEnum
+      responses:
+        '200':
+          description: OK
+  /resolve_parameter_inline_enum_form_parameters:
+    post:
+      requestBody:
+        content:
+          application/x-www-form-urlencoded:
+            schema:
+              type: object
+              properties:
+                enum_form_string_array:
+                  description: Form parameter enum test (string array)
+                  type: array
+                  items:
+                    type: string
+                    default: $
+                    enum:
+                      - '>'
+                      - $
+                enum_form_string:
+                  description: Form parameter enum test (string)
+                  type: string
+                  enum:
+                    - _abc
+                    - '-efg'
+                    - (xyz)
+                  default: '-efg'
+      operationId: resolve_parameter_inline_enum_form_parameters
+      responses:
+        '200':
+          description: OK
   /resolve_request_body_invalid_ref:
     post:
       requestBody: