Define and verify behavior of schema extension properties

api/pom.xml

@@ -33,6 +33,12 @@
             <artifactId>osgi.annotation</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>biz.aQute.bnd</groupId>
+            <artifactId>biz.aQute.bnd.annotation</artifactId>
+            <version>7.0.0</version>
+            <scope>provided</scope>
+        </dependency>
     </dependencies>
 
     <build>

api/src/main/java/module-info.java

@@ -52,5 +52,5 @@
 
     // Required for compilation, not used at runtime
     requires static osgi.annotation;
-
+    requires static biz.aQute.bnd.annotation;
 }

api/src/main/java/org/eclipse/microprofile/openapi/models/Extensible.java

@@ -23,19 +23,24 @@
  * The base interface for OpenAPI model objects that can contain extensions. Extensions contain data not required by the
  * specification and may or may not be supported by the tools you use.
  * <p>
- * The extensions property names are always prefixed by "x-".
+ * The extension's property names are always prefixed by "x-" unless otherwise specified by sub-interfaces or Extensible
+ * methods overridden therein. Sub-interfaces may also include additional detail regarding the handling of extension
+ * properties and how they relate to other well-known properties of the interface.
+ *
+ * For example, {@link org.eclipse.microprofile.openapi.models.media.Schema Schema} defines such handling and relaxes
+ * the requirement that extension properties are prefixed by "x-".
  */
 public interface Extensible<T extends Extensible<T>> {
 
     /**
-     * Returns the extensions property from an Extensible instance.
+     * Returns the map of all extension properties from an Extensible instance.
      *
      * @return a map containing keys which start with "x-" and values which provide additional information
      **/
     Map<String, Object> getExtensions();
 
     /**
-     * Sets this Extensible's extensions property to the given map of extensions.
+     * Sets this Extensible's extension properties to the given map of extensions.
      *
      * @param extensions
      *            map containing keys which start with "x-" and values which provide additional information
@@ -49,7 +54,7 @@ default T extensions(Map<String, Object> extensions) {
     }
 
     /**
-     * Adds the given object to this Extensible's map of extensions, with the given name as its key.
+     * Adds the given extension property to this Extensible, with the given name as its key.
      *
      * @param name
      *            the key used to access the extension object. Always prefixed by "x-".
@@ -61,23 +66,23 @@ default T extensions(Map<String, Object> extensions) {
     T addExtension(String name, Object value);
 
     /**
-     * Removes the given object to this Extensible's map of extensions, with the given name as its key.
+     * Removes an extension with the given property name from this Extensible.
      *
      * @param name
      *            the key used to access the extension object. Always prefixed by "x-".
      */
     void removeExtension(String name);
 
     /**
-     * Sets this Extensible's extensions property to the given map of extensions.
+     * Sets this Extensible's extension properties to the given map of extensions.
      *
      * @param extensions
      *            map containing keys which start with "x-" and values which provide additional information
      */
     void setExtensions(Map<String, Object> extensions);
 
     /**
-     * Checks whether an extension with the given name is present in this Extensible's map of extensions.
+     * Checks whether an extension with the given name is present in this Extensible.
      *
      * @param name
      *            the key used to access the extension object. Always prefixed by "x-".
@@ -93,7 +98,7 @@ default boolean hasExtension(String name) {
     }
 
     /**
-     * Returns the extension object with the given name from this Extensible's map of extensions.
+     * Returns the object with the given name from this Extensible's extensions.
      *
      * @param name
      *            the key used to access the extension object. Always prefixed by "x-".

api/src/main/java/org/eclipse/microprofile/openapi/models/media/Schema.java

@@ -39,6 +39,13 @@
  * Any time a Schema Object can be used, a Reference Object can be used in its place. This allows referencing an
  * existing definition instead of defining the same Schema again.
  *
+ * <h3 id="schema-extensions">Extensions</h3> Although Schema is {@link Extensible}, the behavior of extensions is only
+ * defined for the OAS schema dialect identified by URI {@code https://spec.openapis.org/oas/3.1/dialect/base} (the
+ * default if not specified). For this dialect, Schema instances will consider all unknown properties to be extensions.
+ *
+ * The behavior is undefined when adding an extension via one of the methods of the {@link Extensible} interface when
+ * the name of the extension matches the name of a standard OAS schema property.
+ *
  * @see <a href= "https://spec.openapis.org/oas/v3.1.0.html#schema-object">OpenAPI Specification Schema Object</a>
  */
 public interface Schema extends Extensible<Schema>, Constructible, Reference<Schema> {
@@ -2060,6 +2067,9 @@ default Schema examples(List<Object> examples) {
      * }
      * </pre>
      *
+     * <p>
+     * Note, if the property is an extension, this method is equivalent to {@link #getExtension(String)}.
+     *
      * @param propertyName
      *            the property name
      * @return the value of the named property, or {@code null} if a property with the given name is not set
@@ -2090,7 +2100,8 @@ default Schema examples(List<Object> examples) {
      * </ul>
      *
      * <p>
-     * When using the standard schema dialect, values set by this method can be retrieved by other methods. E.g.
+     * When using the standard schema dialect, values set by this method can be retrieved by other methods provided the
+     * type is compatible. E.g.
      *
      * <pre>
      * {@code
@@ -2099,6 +2110,9 @@ default Schema examples(List<Object> examples) {
      * }
      * </pre>
      *
+     * <p>
+     * Note, if the property is an extension, this method is equivalent to {@link #addExtension(String, Object)}.
+     *
      * @param propertyName
      *            the property name
      * @param value
@@ -2122,12 +2136,104 @@ default Schema examples(List<Object> examples) {
     /**
      * Sets all properties of a schema.
      * <p>
-     * Equivalent to clearing all properties and then setting each property with {@link #set(String, Object)}.
+     * Equivalent to clearing all properties, including extensions, and then setting each property with
+     * {@link #set(String, Object)}.
      *
      * @param allProperties
      *            the properties to set. Each value in the map must be valid according to the rules in
      *            {@link #set(String, Object)}
      * @since 4.0
      */
     void setAll(Map<String, ?> allProperties);
+
+    /**
+     * Returns the map of all extension properties of the schema.
+     *
+     * @return a map containing all of this schema's extension properties
+     *
+     * @see <a href="#schema-extensions">Schema Extensions</a>
+     **/
+    @Override
+    Map<String, Object> getExtensions();
+
+    /**
+     * Sets this schema's extension properties to the given map of extensions. Passing an empty map has the effect of
+     * clearing all existing extension properties.
+     *
+     * @param extensions
+     *            map containing the extension properties for this schema
+     * @return the current instance
+     *
+     * @see <a href="#schema-extensions">Schema Extensions</a>
+     */
+    @Override
+    @aQute.bnd.annotation.baseline.BaselineIgnore("4.2.0")
+    default Schema extensions(Map<String, Object> extensions) {
+        return Extensible.super.extensions(extensions);
+    }
+
+    /**
+     * Sets a schema extension property.
+     *
+     * @param name
+     *            the extension property name
+     * @param value
+     *            extension property value. null values will be rejected (implementation will throw an exception) or
+     *            ignored.
+     * @return the current instance
+     *
+     * @see <a href="#schema-extensions">Schema Extensions</a>
+     */
+    @Override
+    @aQute.bnd.annotation.baseline.BaselineIgnore("4.2.0")
+    Schema addExtension(String name, Object value);
+
+    /**
+     * Removes the given extension property from the schema.
+     *
+     * @param name
+     *            the extension property name
+     *
+     * @see <a href="#schema-extensions">Schema Extensions</a>
+     */
+    @Override
+    void removeExtension(String name);
+
+    /**
+     * Sets this schema's extension properties to the given map of extensions. Passing an empty map has the effect of
+     * clearing all existing extension properties.
+     *
+     * @param extensions
+     *            map containing the extension properties for this schema
+     *
+     * @see <a href="#schema-extensions">Schema Extensions</a>
+     */
+    @Override
+    void setExtensions(Map<String, Object> extensions);
+
+    /**
+     * Checks whether an extension property with the given name is present on this schema.
+     *
+     * @param name
+     *            the extension property name
+     *
+     * @return {@code true} if an extension with the given name is present, otherwise {@code false}
+     */
+    @Override
+    default boolean hasExtension(String name) {
+        return Extensible.super.hasExtension(name);
+    }
+
+    /**
+     * Returns the extension object with the given name from this schema.
+     *
+     * @param name
+     *            the extension property name
+     *
+     * @return the corresponding extension object, or {@code null} if no extension with the given name is present
+     */
+    @Override
+    default Object getExtension(String name) {
+        return Extensible.super.getExtension(name);
+    }
 }

api/src/main/java/org/eclipse/microprofile/openapi/models/media/package-info.java

@@ -30,6 +30,6 @@
  * </pre>
  */
 
-@org.osgi.annotation.versioning.Version("3.1")
+@org.osgi.annotation.versioning.Version("3.2")
 @org.osgi.annotation.versioning.ProviderType
 package org.eclipse.microprofile.openapi.models.media;

spec/src/main/asciidoc/release_notes.asciidoc

@@ -28,6 +28,7 @@ A full list of changes delivered in the 4.2 release can be found at link:https:/
 ==== API/SPI changes
 
 * Add `example` and `examples` to `@Header` and verify implementation support in TCK (https://github.com/microprofile/microprofile-open-api/issues/697)[697])
+* Override `@Extensible`'s methods in `@Schema`, providing clarification in the documentation on how the methods behave specifically for schemas (https://github.com/microprofile/microprofile-open-api/issues/698[698])
 
 [[other_changes_42]]
 ==== Other Changes

tck/src/main/java/org/eclipse/microprofile/openapi/tck/SchemaExtensionPropertyTest.java

@@ -0,0 +1,104 @@
+/**
+ * Copyright (c) 2026 Contributors to the Eclipse Foundation
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.eclipse.microprofile.openapi.tck;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.sameInstance;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+import org.eclipse.microprofile.openapi.OASFactory;
+import org.eclipse.microprofile.openapi.models.media.Schema;
+import org.eclipse.microprofile.openapi.models.media.Schema.SchemaType;
+import org.testng.annotations.Test;
+
+/**
+ * This test covers the Extensible aspect of the Schema model, checking that properties are recognized correctly as
+ * extensions by an implementation and handled according to the Schema documentation.
+ */
+public class SchemaExtensionPropertyTest {
+
+    private static final String EXTNAME = "my-extension";
+
+    @Test
+    public void testExtensionSetForUnknownProperty() {
+        Schema schema = OASFactory.createSchema();
+        Object theExtension = new Object();
+        schema.set(EXTNAME, theExtension);
+
+        assertThat(schema.get(EXTNAME), is(sameInstance(theExtension)));
+        assertThat(schema.getExtension(EXTNAME), is(sameInstance(theExtension)));
+    }
+
+    @Test
+    public void testExtensionSetAllForUnknownProperty() {
+        Schema schema = OASFactory.createSchema();
+        Object theExtension = new Object();
+        schema.setAll(Map.of(
+                "type", List.of(SchemaType.STRING),
+                EXTNAME, theExtension));
+
+        assertThat(schema.getType(), is(List.of(SchemaType.STRING)));
+        assertThat(schema.get(EXTNAME), is(sameInstance(theExtension)));
+        assertThat(schema.getExtension(EXTNAME), is(sameInstance(theExtension)));
+    }
+
+    @Test
+    public void testExtensionAvailableFromGet() {
+        Schema schema = OASFactory.createSchema();
+        Object theExtension = new Object();
+        schema.addExtension(EXTNAME, theExtension);
+
+        assertThat(schema.get(EXTNAME), is(sameInstance(theExtension)));
+        assertThat(schema.getExtension(EXTNAME), is(sameInstance(theExtension)));
+    }
+
+    @Test
+    public void testExtensionSetWithNonnullDialect() {
+        Schema schema = OASFactory.createSchema();
+        schema.setSchemaDialect("https://spec.openapis.org/oas/3.1/dialect/base");
+        Object theExtension = new Object();
+        schema.set(EXTNAME, theExtension);
+        assertThat(schema.getExtension(EXTNAME), is(sameInstance(theExtension)));
+    }
+
+    @Test
+    public void testSetAllClearsExtensions() {
+        Schema schema = OASFactory.createSchema();
+        Object theExtension = new Object();
+        schema.set(EXTNAME, theExtension);
+        assertThat(schema.getExtension(EXTNAME), is(sameInstance(theExtension)));
+        schema.setAll(Collections.emptyMap());
+        assertThat(schema.hasExtension(EXTNAME), is(false));
+    }
+
+    @Test
+    public void testNullExtensionNotAdded() {
+        Schema schema = OASFactory.createSchema();
+
+        try {
+            schema.addExtension(EXTNAME, null);
+        } catch (Exception e) {
+            // May or may not be thrown
+        }
+
+        assertThat(schema.hasExtension(EXTNAME), is(false));
+    }
+}