graphql-java · xuorig · Jul 2, 2025 · Jul 3, 2025 · Jul 3, 2025 · Jul 3, 2025
diff --git a/src/main/java/graphql/schema/idl/TypeDefinitionRegistry.java b/src/main/java/graphql/schema/idl/TypeDefinitionRegistry.java
@@ -623,9 +623,25 @@ public boolean isPossibleType(Type abstractType, Type possibleType) {
             return false;
         } else {
             InterfaceTypeDefinition iFace = (InterfaceTypeDefinition) abstractTypeDef;
-            List<ImplementingTypeDefinition> implementingTypeDefinitions = getAllImplementationsOf(iFace);
-            return implementingTypeDefinitions.stream()
-                    .anyMatch(od -> od.getName().equals(targetObjectTypeDef.getName()));
+
+            for (TypeDefinition<?> t : types.values()) {
+                if (t instanceof ImplementingTypeDefinition) {
+                    if (t.getName().equals(targetObjectTypeDef.getName())) {
+                        ImplementingTypeDefinition<?> itd = (ImplementingTypeDefinition<?>) t;
+
+                        for (Type impl : itd.getImplements()) {
+                            TypeName typeName = TypeInfo.getTypeName(impl);
+                            TypeDefinition<?> matchingInterface = types.get(typeName.getName());
+
+                            if (matchingInterface != null && matchingInterface.getName().equals(iFace.getName())) {
+                                return true;
+                            }
+                        }
+                    }
+                }
+            }
+
+            return false;
         }
     }
 

diff --git a/src/main/java/graphql/schema/idl/TypeInfo.java b/src/main/java/graphql/schema/idl/TypeInfo.java
@@ -26,6 +26,25 @@ public static TypeInfo typeInfo(Type type) {
         return new TypeInfo(type);
     }
 
+    /**
+     * Gets the type name of a [Type], unwrapping any lists or non-null decorations
+     *
+     * @param type the Type
+     *
+     * @return the inner TypeName for this type
+     */
+    public static TypeName getTypeName(Type type) {
+        while (!(type instanceof TypeName)) {
+            if (type instanceof NonNullType) {
+                type = ((NonNullType) type).getType();
+            }
+            if (type instanceof ListType) {
+                type = ((ListType) type).getType();
+            }
+        }
+        return (TypeName) type;
+    }
+
     private final Type rawType;
     private final TypeName typeName;
     private final Deque<Class<?>> decoration = new ArrayDeque<>();

diff --git a/src/test/groovy/graphql/schema/idl/TypeInfoTest.groovy b/src/test/groovy/graphql/schema/idl/TypeInfoTest.groovy
@@ -136,4 +136,21 @@ class TypeInfoTest extends Specification {
         "[named!]!"   | "[newName!]!"
         "[[named!]!]" | "[[newName!]!]"
     }
+
+    def "test getTypeName gets to the inner type"() {
+
+        expect:
+        Type actualType = TestUtil.parseType(actual)
+        def typeName = TypeInfo.getTypeName(actualType)
+        typeName.getName() == expected
+
+        where:
+        actual        | expected
+        "named"       | "named"
+        "named!"      | "named"
+        "[named]"     | "named"
+        "[named!]"    | "named"
+        "[named!]!"   | "named"
+        "[[named!]!]" | "named"
+    }
 }