[openapi-normalizer] add a new rule to set tags for all operations (#14794)

* add doc for KEEP_ONLY_FIRST_TAG_IN_OPERATION

* add new rule SET_TAGS_FOR_ALL_OPERATIONS

* better null check

* improve doc

docs/customization.md

@@ -491,3 +491,17 @@ Example:
 ```
 java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -g java -i modules/openapi-generator/src/test/resources/3_0/simplifyOneOfAnyOf_test.yaml -o /tmp/java-okhttp/ --openapi-normalizer SIMPLIFY_ONEOF_ANYOF=true
 ```
+
+- `KEEP_ONLY_FIRST_TAG_IN_OPERATION`: when set to `true`, only keep the first tag in operation if there are more than one tag defined.
+
+Example:
+```
+java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -g java -i modules/openapi-generator/src/test/resources/3_0/enableKeepOnlyFirstTagInOperation_test.yaml -o /tmp/java-okhttp/ --openapi-normalizer KEEP_ONLY_FIRST_TAG_IN_OPERATION=true
+```
+
+- `SET_TAGS_FOR_ALL_OPERATIONS`: when set to a string value, tags in all operatinos will reset to the string value provided.
+
+Example:
+```
+java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -g java -i modules/openapi-generator/src/test/resources/3_0/enableKeepOnlyFirstTagInOperation_test.yaml -o /tmp/java-okhttp/ --openapi-normalizer SET_TAGS_FOR_ALL_OPERATIONS=true
+```

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

@@ -39,7 +39,7 @@ public class OpenAPINormalizer {
     final Logger LOGGER = LoggerFactory.getLogger(OpenAPINormalizer.class);
 
     // ============= a list of rules =============
-    // when set to true, all rules are enabled
+    // when set to true, all rules (true or false) are enabled
     final String ALL = "ALL";
     boolean enableAll;
 
@@ -72,6 +72,10 @@ public class OpenAPINormalizer {
     final String SIMPLIFY_BOOLEAN_ENUM = "SIMPLIFY_BOOLEAN_ENUM";
     boolean simplifyBooleanEnum;
 
+    // when set to a string value, tags in all operations will be reset to the string value provided
+    final String SET_TAGS_FOR_ALL_OPERATIONS = "SET_TAGS_FOR_ALL_OPERATIONS";
+    String setTagsForAllOperations;
+
     // ============= end of rules =============
 
     /**
@@ -123,6 +127,11 @@ public class OpenAPINormalizer {
         if (enableAll || "true".equalsIgnoreCase(rules.get(SIMPLIFY_BOOLEAN_ENUM))) {
             simplifyBooleanEnum = true;
         }
+
+        if (StringUtils.isNotEmpty(rules.get(SET_TAGS_FOR_ALL_OPERATIONS))) {
+            setTagsForAllOperations = rules.get(SET_TAGS_FOR_ALL_OPERATIONS);
+        }
+
     }
 
     /**
@@ -186,6 +195,8 @@ public class OpenAPINormalizer {
      */
     private void normalizeOperation(Operation operation) {
         processKeepOnlyFirstTagInOperation(operation);
+
+        processSetTagsForAllOperations(operation);
     }
 
     /**
@@ -501,6 +512,20 @@ public class OpenAPINormalizer {
         }
     }
 
+    /**
+     * Set the tag name for all operations
+     *
+     * @param operation Operation
+     */
+    private void processSetTagsForAllOperations(Operation operation) {
+        if (StringUtils.isEmpty(setTagsForAllOperations)) {
+            return;
+        }
+
+        operation.setTags(null);
+        operation.addTagsItem(setTagsForAllOperations);
+    }
+
     /**
      * If the schema contains anyOf/oneOf and properties, remove oneOf/anyOf as these serve as rules to
      * ensure inter-dependency between properties. It's a workaround as such validation is not supported at the moment.
@@ -534,6 +559,11 @@ public class OpenAPINormalizer {
             return schema;
         }
 
+        if (schema.getAnyOf() == null) {
+            // ComposedSchema, Schema with `type: null`
+            return schema;
+        }
+
         Schema s0 = null, s1 = null;
         if (schema.getAnyOf().size() == 2) {
             s0 = ModelUtils.unaliasSchema(openAPI, (Schema) schema.getAnyOf().get(0));

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

@@ -4453,4 +4453,22 @@ public class DefaultCodegenTest {
         BooleanSchema bs2 = (BooleanSchema) schema.getProperties().get("boolean_enum");
         assertNull(bs2.getEnum()); //ensure the enum has been erased
     }
+
+    @Test
+    public void testOpenAPINormalizerSetTagsInAllOperations() {
+        OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/enableKeepOnlyFirstTagInOperation_test.yaml");
+
+        assertEquals(openAPI.getPaths().get("/person/display/{personId}").getGet().getTags().size(), 2);
+        assertEquals(openAPI.getPaths().get("/person/display/{personId}").getDelete().getTags().size(), 1);
+
+        Map<String, String> options = new HashMap<>();
+        options.put("SET_TAGS_FOR_ALL_OPERATIONS", "core");
+        OpenAPINormalizer openAPINormalizer = new OpenAPINormalizer(openAPI, options);
+        openAPINormalizer.normalize();
+
+        assertEquals(openAPI.getPaths().get("/person/display/{personId}").getGet().getTags().size(), 1);
+        assertEquals(openAPI.getPaths().get("/person/display/{personId}").getDelete().getTags().size(), 1);
+        assertEquals(openAPI.getPaths().get("/person/display/{personId}").getGet().getTags().get(0), "core");
+        assertEquals(openAPI.getPaths().get("/person/display/{personId}").getDelete().getTags().get(0), "core");
+    }
 }