fix: resolve $ref inside allOf of unreferenced component schemas

modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/util/ResolverFully.java

@@ -133,6 +133,19 @@ public void resolveFully(OpenAPI openAPI) {
                 resolvePath(pathItem);
             }
         }
+
+        // Resolve component schemas that are not reachable through any path, so that
+        // e.g. a $ref inside an allOf of an otherwise-unreferenced component schema is
+        // still fully resolved. resolveSchema caches its results, so component schemas
+        // already resolved while walking the paths are returned as-is (no double resolution).
+        if (schemas != null) {
+            for (String schemaName : new ArrayList<>(schemas.keySet())) {
+                Schema resolved = resolveSchema(schemas.get(schemaName));
+                if (resolved != null) {
+                    schemas.put(schemaName, resolved);
+                }
+            }
+        }
     }
 
     public void resolvePath(PathItem pathItem){

modules/swagger-parser-v3/src/test/java/io/swagger/v3/parser/test/Issue2270Test.java

@@ -0,0 +1,42 @@
+package io.swagger.v3.parser.test;
+
+import io.swagger.v3.oas.models.media.Schema;
+import io.swagger.v3.parser.OpenAPIV3Parser;
+import io.swagger.v3.parser.core.models.ParseOptions;
+import io.swagger.v3.parser.core.models.SwaggerParseResult;
+import org.junit.Test;
+
+import java.util.List;
+
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+public class Issue2270Test {
+
+    @Test
+    public void shouldResolveRefInsideAllOfOfUnreferencedComponentSchema() {
+        ParseOptions options = new ParseOptions();
+        options.setResolveFully(true);
+        // Keep the allOf structure so we can assert the inner $ref itself was resolved.
+        options.setResolveCombinators(false);
+
+        SwaggerParseResult result = new OpenAPIV3Parser().readLocation("issue-2270/openapi.yaml", null, options);
+
+        assertNotNull(result.getOpenAPI());
+        Schema<?> contact = result.getOpenAPI().getComponents().getSchemas().get("Contact");
+        assertNotNull(contact);
+
+        List<Schema> allOf = contact.getAllOf();
+        assertNotNull(allOf);
+
+        // The first allOf member is a $ref to SObject and, although Contact is not reachable
+        // through any path, resolveFully(true) must still resolve it: the $ref must be gone
+        // and the referenced schema's properties must be inlined.
+        Schema<?> firstMember = allOf.get(0);
+        assertNull("$ref inside allOf of an unreferenced component schema was not resolved",
+                firstMember.get$ref());
+        assertNotNull(firstMember.getProperties());
+        assertTrue(firstMember.getProperties().containsKey("id"));
+    }
+}

modules/swagger-parser-v3/src/test/resources/issue-2270/openapi.yaml

@@ -0,0 +1,19 @@
+openapi: 3.0.1
+info:
+  title: issue-2270
+  version: 1.0.0
+paths: {}
+components:
+  schemas:
+    SObject:
+      type: object
+      properties:
+        id:
+          type: string
+    Contact:
+      allOf:
+        - $ref: '#/components/schemas/SObject'
+        - type: object
+          properties:
+            name:
+              type: string