Correctly resolve externalRefs that point to the root path

modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/ResolverCache.java

@@ -30,6 +30,7 @@
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
 import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -108,17 +109,25 @@ public ResolverCache(OpenAPI openApi, List<AuthorizationValue> auths, String par
 
     }
 
+    private <T> T loadSchemaForInternalRef(String ref, Class<T> expectedType) {
+        Object loadedRef = loadInternalRef(ref);
+
+        try{
+            return expectedType.cast(loadedRef);
+        }
+        catch (Exception e) {
+            return null;
+        }
+    }
+
+    private boolean fileIsRootPath(Path file) {
+        return this.rootPath != null && file.normalize().equals(Paths.get(this.rootPath).toAbsolutePath().normalize());
+    }
+
     public <T> T loadRef(String ref, RefFormat refFormat, Class<T> expectedType) {
         if (refFormat == RefFormat.INTERNAL) {
             //we don't need to go get anything for internal refs
-            Object loadedRef = loadInternalRef(ref);
-
-            try{
-                return expectedType.cast(loadedRef);
-            }
-            catch (Exception e) {
-                return null;
-            }
+            return loadSchemaForInternalRef(ref, expectedType);
         }
 
         final String[] refParts = ref.split("#/");
@@ -130,6 +139,12 @@ public <T> T loadRef(String ref, RefFormat refFormat, Class<T> expectedType) {
         final String file = refParts[0];
         final String definitionPath = refParts.length == 2 ? refParts[1] : null;
 
+        if (this.parentDirectory != null && fileIsRootPath(this.parentDirectory.resolve(file))) {
+            // If the file part of this external ref refers to the same file as the root path, we can treat it like an
+            // internal ref.
+            return loadSchemaForInternalRef("#/" + definitionPath, expectedType);
+        }
+
         //we might have already resolved this ref, so check the resolutionCache
         Object previouslyResolvedEntity = resolutionCache.get(ref);
 

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

@@ -0,0 +1,18 @@
+package io.swagger.v3.parser.test;
+
+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 static org.testng.Assert.assertFalse;
+
+public class ResolverCacheCircularTest {
+    @Test
+    public void testIssue1961_DuplicateSchemas_ABA() throws Exception {
+        ParseOptions parseOptions = new ParseOptions();
+        parseOptions.setResolve(true);
+        SwaggerParseResult result = new OpenAPIV3Parser().readLocation("src/test/resources/issue-1961/Foo.yaml", null, parseOptions);
+        assertFalse(result.getOpenAPI().getComponents().getSchemas().containsKey("FooBar_1"));
+    }
+}

modules/swagger-parser-v3/src/test/resources/issue-1961/Bar.yaml

@@ -0,0 +1,13 @@
+components:
+  schemas:
+    Bar:
+      anyOf:
+      - $ref: ./Foo.yaml#/components/schemas/FooBar
+    BarType:
+      enum:
+      - All
+      - OEM
+      type: string
+info:
+  title: '#Issue1961.Bar'
+openapi: 3.0.1

modules/swagger-parser-v3/src/test/resources/issue-1961/Foo.yaml

@@ -0,0 +1,17 @@
+components:
+  schemas:
+    FooBar:
+      properties:
+        BypassTypes:
+          items:
+            $ref: ./Bar.yaml#/components/schemas/BarType
+          type: array
+      type: object
+    Foo:
+      properties:
+        MFABypass:
+          $ref: ./Bar.yaml#/components/schemas/Bar
+      type: object
+info:
+  title: '#Issue1961.Foo'
+openapi: 3.0.1