fix(normalizer): restore behavior of clearing a oneOf if the schema content cannot currently be used by the generator (#24585)

Author: Mattias-Sehlstedt

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

@@ -43,6 +43,7 @@
 import static org.openapitools.codegen.CodegenConstants.*;
 import static org.openapitools.codegen.utils.EnumUtils.ANY_OF;
 import static org.openapitools.codegen.utils.EnumUtils.ONE_OF;
+import static org.openapitools.codegen.utils.ModelUtils.isOneOfOfConsts;
 import static org.openapitools.codegen.utils.ModelUtils.simplifyOneOfAnyOfWithOnlyOneNonNullSubSchema;
 import static org.openapitools.codegen.utils.StringUtils.getUniqueString;
 
@@ -1742,18 +1743,24 @@ protected Schema processSimplifyOneOf(Schema schema) {
             }
 
             schema = simplifyOneOfAnyOfWithOnlyOneNonNullSubSchema(openAPI, schema, oneOfSchemas);
-            if (ModelUtils.isIntegerSchema(schema) || ModelUtils.isNumberSchema(schema) || ModelUtils.isStringSchema(schema)) {
-                if (schema.getSpecVersion().equals(SpecVersion.V30)) {
-                    schema.setOneOf(null);
-                } //else {
-                    // TODO convert oneOf const/deprecated to enum
-               // }
-            }
+            clearOneOf(schema);
         }
 
         return schema;
     }
 
+    /**
+     * Removes the {@code oneOf} from the schema if it is considered to not contain information that the generator can
+     * currently act upon. The schema is left untouched if all the {@code oneOf} branches contain an OAS 3.1 {@code const}.
+     * This since that structure can potentially be used for enum interpretation.
+     */
+    private void clearOneOf(Schema schema) {
+        if (ModelUtils.isIntegerSchema(schema) || ModelUtils.isNumberSchema(schema) || ModelUtils.isStringSchema(schema)) {
+            if (!isOneOfOfConsts(schema)) {
+                schema.setOneOf(null);
+            }
+        }
+    }
 
     /**
      * Ensure inheritance is correctly defined for OneOf and Discriminators.

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

@@ -2847,6 +2847,19 @@ public static boolean containsEnums(OpenAPI openAPI) {
         return schemaMap.values().stream().anyMatch(ModelUtils::isEnumSchema);
     }
 
+    /**
+     * Whether all branches in the oneOf contains a {@code const}. Returns false for OAS 3.0 since that does not support
+     * {@code const}.
+     * @param schema The Schema
+     * @return true if all {@code oneOf} branches contains a {@code const}.
+     */
+    public static boolean isOneOfOfConsts(Schema<?> schema) {
+        if (hasOneOf(schema) && !schema.getSpecVersion().equals(SpecVersion.V30)) {
+            return schema.getOneOf().stream().allMatch(oneOf -> oneOf.getConst() != null);
+        }
+        return false;
+    }
+
     @FunctionalInterface
     private interface OpenAPISchemaVisitor {
 

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

@@ -43,6 +43,8 @@
 
 public class OpenAPINormalizerTest {
 
+    private static final String SIMPLIFY_ONE_OF_ANY_OF = "SIMPLIFY_ONEOF_ANYOF";
+    private static final String SIMPLIFY_ONEOF_ANYOF_ENUM = "SIMPLIFY_ONEOF_ANYOF_ENUM";
     private static final String REF_AS_PARENT_IN_ALLOF = "REF_AS_PARENT_IN_ALLOF";
     private static final String X_PARENT = "x-parent";
     private static final String X_INTERNAL = "x-internal";
@@ -210,7 +212,7 @@ public void testSimplifyOneOfAnyOfEnum() throws Exception {
 
         // Test with rule enabled (default)
         Map<String, String> options = new HashMap<>();
-        options.put("SIMPLIFY_ONEOF_ANYOF_ENUM", "true");
+        options.put(SIMPLIFY_ONEOF_ANYOF_ENUM, "true");
         OpenAPINormalizer normalizer = new OpenAPINormalizer(openAPI, options);
         normalizer.normalize();
 
@@ -248,7 +250,7 @@ public void testSimplifyOneOfAnyOfEnum() throws Exception {
         // Test with rule disabled
         OpenAPI openAPI2 = TestUtils.parseSpec("src/test/resources/3_0/simplifyOneOfWithEnums_test.yaml");
         Map<String, String> options2 = new HashMap<>();
-        options2.put("SIMPLIFY_ONEOF_ANYOF_ENUM", "false");
+        options2.put(SIMPLIFY_ONEOF_ANYOF_ENUM, "false");
         OpenAPINormalizer normalizer2 = new OpenAPINormalizer(openAPI2, options2);
         normalizer2.normalize();
 
@@ -312,7 +314,7 @@ public void testOpenAPINormalizerSimplifyOneOfAnyOf() {
         assertEquals(schema19.getAnyOf().size(), 1);
 
         Map<String, String> options = new HashMap<>();
-        options.put("SIMPLIFY_ONEOF_ANYOF", "true");
+        options.put(SIMPLIFY_ONE_OF_ANY_OF, "true");
         OpenAPINormalizer openAPINormalizer = new OpenAPINormalizer(openAPI, options);
         openAPINormalizer.normalize();
 
@@ -370,7 +372,7 @@ public void testOpenAPINormalizerSimplifyOneOfWithSingleRef() {
         assertEquals(((Schema) oneOfWithSingleRef.getProperties().get("number")).getOneOf().size(), 1);
 
         Map<String, String> options = new HashMap<>();
-        options.put("SIMPLIFY_ONEOF_ANYOF", "true");
+        options.put(SIMPLIFY_ONE_OF_ANY_OF, "true");
         OpenAPINormalizer openAPINormalizer = new OpenAPINormalizer(openAPI, options);
         openAPINormalizer.normalize();
 
@@ -511,7 +513,7 @@ public void testOpenAPINormalizerConvertEnumNullToNullable() {
         assertNull(schema.getNullable());
 
         Map<String, String> options = new HashMap<>();
-        options.put("SIMPLIFY_ONEOF_ANYOF", "true");
+        options.put(SIMPLIFY_ONE_OF_ANY_OF, "true");
         OpenAPINormalizer openAPINormalizer = new OpenAPINormalizer(openAPI, options);
         openAPINormalizer.normalize();
 
@@ -1539,7 +1541,7 @@ public void testOpenAPINormalizerSimplifyOneOfAnyOf31Spec() {
 
         // start the normalization
         Map<String, String> options = new HashMap<>();
-        options.put("SIMPLIFY_ONEOF_ANYOF", "true");
+        options.put(SIMPLIFY_ONE_OF_ANY_OF, "true");
         OpenAPINormalizer openAPINormalizer = new OpenAPINormalizer(openAPI, options);
         openAPINormalizer.normalize();
 
@@ -1613,6 +1615,40 @@ public void testOpenAPINormalizerSimplifyOneOfAnyOf31Spec() {
         assertEquals(((Schema) schema24.getProperties().get("anyof_nullable_number")).getTypes().size(), 1);
     }
 
+    @Test
+    public void testOneOfWithStringsWithDifferentPatternsAreCollapsedWithSimplifyOneOfAnyOf() {
+        OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_1/simplifyOneOfAnyOf_test.yaml");
+
+        Schema stringPatternsWithOneOf = openAPI.getComponents().getSchemas().get("StringPatternsWithOneOf");
+        assertEquals(stringPatternsWithOneOf.getOneOf().size(), 2);
+
+        // start the normalization
+        Map<String, String> options = new HashMap<>();
+        options.put(SIMPLIFY_ONE_OF_ANY_OF, "true");
+        OpenAPINormalizer openAPINormalizer = new OpenAPINormalizer(openAPI, options);
+        openAPINormalizer.normalize();
+
+        Schema normalizedStringPatternsWithOneOf = openAPI.getComponents().getSchemas().get("StringPatternsWithOneOf");
+        assertNull(normalizedStringPatternsWithOneOf.getOneOf());
+    }
+
+    @Test
+    public void testOneOfWithConstsIsUntouchedBySimplifyOneOfAnyOf() {
+        OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_1/simplifyOneOfAnyOf_test.yaml");
+
+        Schema integerWithOneOfConsts = openAPI.getComponents().getSchemas().get("TypeIntegerWithOneOf");
+        assertEquals(integerWithOneOfConsts.getOneOf().size(), 3);
+
+        // start the normalization
+        Map<String, String> options = new HashMap<>();
+        options.put(SIMPLIFY_ONEOF_ANYOF_ENUM, "false");
+        OpenAPINormalizer openAPINormalizer = new OpenAPINormalizer(openAPI, options);
+        openAPINormalizer.normalize();
+
+        Schema normalizedIntegerWithOneOfConsts = openAPI.getComponents().getSchemas().get("TypeIntegerWithOneOf");
+        assertEquals(normalizedIntegerWithOneOfConsts.getOneOf().size(), 3);
+    }
+
     @Test
     public void testOpenAPINormalizerSimplifyOneOfWithSingleRef31Spec() {
         OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_1/simplifyOneOfAnyOf_test.yaml");
@@ -1621,7 +1657,7 @@ public void testOpenAPINormalizerSimplifyOneOfWithSingleRef31Spec() {
         assertEquals(((Schema) oneOfWithSingleRef.getProperties().get("number")).getOneOf().size(), 1);
 
         Map<String, String> options = new HashMap<>();
-        options.put("SIMPLIFY_ONEOF_ANYOF", "true");
+        options.put(SIMPLIFY_ONE_OF_ANY_OF, "true");
         OpenAPINormalizer openAPINormalizer = new OpenAPINormalizer(openAPI, options);
         openAPINormalizer.normalize();
 

modules/openapi-generator/src/test/resources/3_1/simplifyOneOfAnyOf_test.yaml

@@ -150,4 +150,13 @@ components:
     OneOfNullAndRef3:
       oneOf:
         - $ref: '#/components/schemas/Parent'
-        - type: "null"
+        - type: "null"
+    StringPatternsWithOneOf:
+      type: string
+      oneOf:
+        - type: string
+          description: Numeric identifier
+          pattern: '^\d{1,35}$'
+        - type: string
+          description: UUID identifier
+          pattern: '^[0-9a-f-]{36}$'

samples/client/petstore/csharp/generichost/latest/AnnotatedEnum/api/openapi.yaml

@@ -131,6 +131,8 @@ components:
       allOf:
       - $ref: "#/components/schemas/Parent"
       nullable: true
+    StringPatternsWithOneOf:
+      type: string
     ParentWithPluralOneOfProperty_number:
       oneOf:
       - $ref: "#/components/schemas/Number"