[Bug][typescript-fetch] Typescript fetch one of addtl props imports

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

@@ -787,21 +787,26 @@ private ExtendedCodegenModel processCodeGenModel(ExtendedCodegenModel cm) {
                 .map(CodegenComposedSchemas::getOneOf)
                 .orElse(Collections.emptyList());
 
+        // create a set of any non-primitive, non-array types used in the oneOf schemas which will
+        // need to be imported.
         cm.oneOfModels = oneOfsList.stream()
-                .filter(CodegenProperty::getIsModel)
+                .filter(cp -> !cp.getIsPrimitiveType() && !cp.getIsArray())
                 .map(CodegenProperty::getBaseType)
                 .filter(Objects::nonNull)
                 .collect(Collectors.toCollection(TreeSet::new));
 
+        // create a set of any complex, inner types used by arrays in the oneOf schema (e.g. if
+        // the oneOf uses Array<Foo>, Foo needs to be imported).
         cm.oneOfArrays = oneOfsList.stream()
                 .filter(CodegenProperty::getIsArray)
                 .map(CodegenProperty::getComplexType)
                 .filter(Objects::nonNull)
                 .collect(Collectors.toCollection(TreeSet::new));
 
+        // create a set of primitive types used in the oneOf schemas for use in the to & from
+        // typed JSON methods.
         cm.oneOfPrimitives = oneOfsList.stream()
                 .filter(CodegenProperty::getIsPrimitiveType)
-                .filter(Objects::nonNull)
                 .collect(Collectors.toCollection(HashSet::new));
 
         if (!cm.oneOf.isEmpty()) {
@@ -1485,6 +1490,9 @@ public class ExtendedCodegenModel extends CodegenModel {
         @Getter @Setter
         public Set<String> modelImports = new TreeSet<String>();
 
+        // oneOfModels, oneOfArrays & oneOfPrimitives contain a list of types used in schemas
+        // composed with oneOf and are used to define the import list and the to & from
+        // 'TypedJSON' conversion methods in the composed model classes.
         @Getter @Setter
         public Set<String> oneOfModels = new TreeSet<>();
         @Getter @Setter

modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchClientCodegenTest.java

@@ -7,6 +7,8 @@
 import io.swagger.v3.oas.models.media.Schema;
 import io.swagger.v3.oas.models.media.StringSchema;
 import java.util.Collections;
+import java.util.Locale;
+import java.util.stream.Stream;
 import org.apache.commons.lang3.StringUtils;
 import org.openapitools.codegen.*;
 import org.openapitools.codegen.config.CodegenConfigurator;
@@ -404,6 +406,44 @@ public void testOneOfModelsDoNotImportPrimitiveTypes() throws IOException {
         TestUtils.assertFileContains(testDiscriminatorResponse, "export type TestDiscriminatorResponse = { discriminatorField: 'optionOne' } & OptionOne | { discriminatorField: 'optionTwo' } & OptionTwo");
     }
 
+    /**
+     * Issue #21587
+     * When using oneOf, the Typescript Fetch generator should import modelled types except for
+     * types built-in primitive types, even those marked with additional properties.
+     */
+    @Test()
+    public void testOneOfModelsImportNonPrimitiveTypes() throws IOException {
+        File output = generate(
+            Collections.emptyMap(),
+            "src/test/resources/3_0/typescript-fetch/issue_21587.yaml"
+        );
+
+        Path testResponse = Paths.get(output + "/models/OneOfResponse.ts");
+        TestUtils.assertFileExists(testResponse);
+
+        // Primitive built-in types should not be included. This list is based off the type mappings
+        // and language specific primitive keywords established in the AbstractTypeScriptClientCodegen
+        Stream.of(
+            "Set",
+            "Array",
+            "boolean",
+            "string",
+            "number",
+            "object",
+            "any",
+            "Date",
+            "Error"
+        ).forEach(primitiveType ->
+            TestUtils.assertFileNotContains(
+                testResponse,
+                String.format(Locale.ROOT, "import type { %s } from './%s'", primitiveType, primitiveType)
+            )
+        );
+        TestUtils.assertFileContains(testResponse, "import type { OptionOne } from './OptionOne'");
+        TestUtils.assertFileContains(testResponse, "import type { OptionTwo } from './OptionTwo'");
+        TestUtils.assertFileContains(testResponse, "import type { OptionThree } from './OptionThree'");
+    }
+
     private static File generate(
         Map<String, Object> properties
     ) throws IOException {

modules/openapi-generator/src/test/resources/3_0/typescript-fetch/issue_21587.yaml

@@ -0,0 +1,79 @@
+openapi: 3.0.1
+info:
+  title: Example API
+  version: 1.0.0
+paths:
+  /api/endpoint:
+    get:
+      operationId: GetEndpoint
+      summary: Get endpoint
+      tags:
+        - Examples
+      responses:
+        '200':
+          description: Successful response
+          content:
+            application/json:
+              schema:
+                type: object
+                title: OneOfResponse
+                oneOf:
+                  - $ref: '#/components/schemas/OptionOne'
+                  - $ref: '#/components/schemas/OptionTwo'
+                  - type: array
+                    items:
+                      $ref: '#/components/schemas/OptionThree'
+                  - type: string
+                    enum:
+                      - "fixed-value-a"
+                      - "fixed-value-b"
+                      - "fixed-value-c"
+                  - type: boolean
+                  - type: number
+                  - type: string
+                    format: date
+                  - type: string
+                    format: date-time
+                  - type: integer
+                    format: int64
+                    enum: [10, 20, 30]
+                  - type: array
+                    items:
+                      type: number
+                  - type: array
+                    items:
+                      type: object
+                  - type: array
+                    items:
+                      type: string
+                      enum:
+                        - "oneof-array-enum-a"
+                        - "oneof-array-enum-b"
+                        - "oneof-array-enum-c"
+                  - type: array
+                    items:
+                      type: number
+                    uniqueItems: true
+
+components:
+  schemas:
+    OptionOne:
+      type: object
+      title: OptionOne
+      properties:
+        propOne:
+          type: number
+      additionalProperties: true
+    OptionTwo:
+      type: object
+      title: OptionTwo
+      properties:
+        propTwo:
+          type: string
+    OptionThree:
+      type: object
+      title: OptionThree
+      properties:
+        propThree:
+          type: boolean
+      additionalProperties: true