Resolve same-named schemas from different files as distinct components (fixes #2333)

modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/processors/ExternalRefProcessor.java

@@ -57,19 +57,32 @@ public ExternalRefProcessor(ResolverCache cache, OpenAPI openAPI) {
 
     private String finalNameRec(Map<String, Schema> schemas, String possiblyConflictingDefinitionName, Schema newSchema,
         int iteration) {
+        return finalNameRec(schemas, possiblyConflictingDefinitionName, newSchema, iteration, null);
+    }
+
+    private String finalNameRec(Map<String, Schema> schemas, String possiblyConflictingDefinitionName, Schema newSchema,
+        int iteration, String incomingRef) {
         String tryName =
             iteration == 0 ? possiblyConflictingDefinitionName : possiblyConflictingDefinitionName + "_" + iteration;
         Schema existingModel = schemas.get(tryName);
         if (existingModel != null) {
             if (existingModel.get$ref() != null) {
+                // The name is currently held by a not-yet-resolved external $ref placeholder. It is only safe to
+                // reuse the name when that placeholder targets the same reference we are resolving; otherwise the
+                // placeholder is a distinct schema that would be silently overwritten (see issue #2333).
+                if (incomingRef != null && existingModel.get$ref() != null
+                        && !existingModel.get$ref().equals(incomingRef)) {
+                    LOGGER.debug("A different external $ref already claims the name " + tryName);
+                    return finalNameRec(schemas, possiblyConflictingDefinitionName, newSchema, ++iteration, incomingRef);
+                }
                 // use the new model
                 existingModel = null;
             } else if (!newSchema.equals(existingModel)) {
                 if(cache.getResolutionCache().get(newSchema.get$ref())!= null){
                     return tryName;
                 }
                 LOGGER.debug("A model for " + existingModel + " already exists");
-                return finalNameRec(schemas, possiblyConflictingDefinitionName, newSchema, ++iteration);
+                return finalNameRec(schemas, possiblyConflictingDefinitionName, newSchema, ++iteration, incomingRef);
             }
         }else{
             // validate the name
@@ -111,7 +124,7 @@ public String processRefToExternalSchema(String $ref, RefFormat refFormat) {
         }
 
         final String possiblyConflictingDefinitionName = computeDefinitionName($ref);
-        newRef = finalNameRec(schemas, possiblyConflictingDefinitionName, schema, 0);
+        newRef = finalNameRec(schemas, possiblyConflictingDefinitionName, schema, 0, $ref);
         cache.putRenamedRef($ref, newRef);
         Schema existingModel = schemas.get(newRef);
        if(existingModel != null && existingModel.get$ref() != null) {

modules/swagger-parser-v3/src/test/java/io/swagger/v3/parser/test/Issue2333Test.java

@@ -0,0 +1,57 @@
+package io.swagger.v3.parser.test;
+
+import io.swagger.v3.oas.models.OpenAPI;
+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.testng.annotations.Test;
+
+import java.util.Map;
+
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertNotNull;
+import static org.testng.Assert.assertTrue;
+
+public class Issue2333Test {
+
+    /**
+     * Two schemas defined in different files but sharing the same name (both {@code Pet}) must be resolved as
+     * distinct components. Previously the resolver reused the first model for both references, so a schema that
+     * was still an unresolved external {@code $ref} placeholder was silently overwritten by an unrelated one.
+     */
+    @Test
+    public void referencedModelsWithSameNameFromDifferentFilesAreNotMerged() {
+        ParseOptions options = new ParseOptions();
+        options.setResolve(true);
+        options.setResolveResponses(true);
+
+        SwaggerParseResult result = new OpenAPIV3Parser()
+                .readLocation("./src/test/resources/issue-2333/main.yaml", null, options);
+
+        assertNotNull(result.getOpenAPI());
+        Map<String, Schema> schemas = result.getOpenAPI().getComponents().getSchemas();
+
+        // SomeItem points at inventory.yaml's Pet (the "name" property)
+        Schema someItem = resolve(schemas, schemas.get("SomeItem"));
+        assertNotNull(someItem.getProperties());
+        assertTrue(someItem.getProperties().containsKey("name"),
+                "SomeItem should resolve to inventory.yaml's Pet (name), but was " + someItem.getProperties().keySet());
+        assertEquals(someItem.getProperties().size(), 1);
+
+        // Pet points at pets.yaml's Pet (the "id" property) and must not be overwritten by inventory.yaml's Pet
+        Schema pet = resolve(schemas, schemas.get("Pet"));
+        assertNotNull(pet.getProperties());
+        assertTrue(pet.getProperties().containsKey("id"),
+                "Pet should resolve to pets.yaml's Pet (id), but was " + pet.getProperties().keySet());
+        assertEquals(pet.getProperties().size(), 1);
+    }
+
+    private Schema resolve(Map<String, Schema> schemas, Schema schema) {
+        if (schema != null && schema.get$ref() != null) {
+            String name = schema.get$ref().substring(schema.get$ref().lastIndexOf('/') + 1);
+            return schemas.get(name);
+        }
+        return schema;
+    }
+}

modules/swagger-parser-v3/src/test/resources/issue-2333/inventory.yaml

@@ -0,0 +1,12 @@
+openapi: 3.0.3
+info:
+  title: Inventory API
+  version: 1.0.0
+paths: {}
+components:
+  schemas:
+    Pet:
+      type: object
+      properties:
+        name:
+          type: string

modules/swagger-parser-v3/src/test/resources/issue-2333/main.yaml

@@ -0,0 +1,11 @@
+openapi: 3.0.3
+info:
+  title: Pet Store API
+  version: 1.0.0
+paths: {}
+components:
+  schemas:
+    SomeItem:
+      $ref: "inventory.yaml#/components/schemas/Pet"
+    Pet:
+      $ref: "pets.yaml#/components/schemas/Pet"

modules/swagger-parser-v3/src/test/resources/issue-2333/pets.yaml

@@ -0,0 +1,12 @@
+openapi: 3.0.3
+info:
+  title: Pets API
+  version: 1.0.0
+paths: {}
+components:
+  schemas:
+    Pet:
+      type: object
+      properties:
+        id:
+          type: integer