{"record":{"id":"36c05c812648f8a1","repo":"quarkusio/quarkus","slug":"permissionchecker-method-s-has-return-type-s","errorCode":null,"errorMessage":"@PermissionChecker method '%s' has return type '%s', but only supported return types are 'boolean' and 'Uni'. ","messagePattern":"@PermissionChecker method '(.+?)' has return type '(.+?)', but only supported return types are 'boolean' and 'Uni'\\. ","errorType":"exception","errorClass":"java.lang.RuntimeException","httpStatus":null,"severity":"error","filePath":"extensions/security/deployment/src/main/java/io/quarkus/security/deployment/PermissionSecurityChecks.java","lineNumber":143,"sourceCode":" private static Map getPermissionCheckers(IndexView index) {\n int permissionCheckerIndex = 0; // this ensures generated QuarkusPermission name is unique\n var permissionCheckers = new HashMap();\n for (var annotationInstance : index.getAnnotations(PERMISSION_CHECKER_NAME)) {\n var checkerMethod = annotationInstance.target().asMethod();\n if (Modifier.isPrivate(checkerMethod.flags())) {\n // we generate QuarkusPermission in the same package as where the @PermissionChecker is detected\n // so the checker method must be either public or package-private\n throw new RuntimeException(\"Private method '\" + toString(checkerMethod)\n + \"' cannot be annotated with the @PermissionChecker annotation\");\n }\n if (Modifier.isStatic(checkerMethod.flags())) {\n // checkers must be CDI bean member methods for now, so the checker method must not be static\n throw new RuntimeException(\"Static method '\" + toString(checkerMethod)\n + \"' cannot be annotated with the @PermissionChecker annotation\");\n }\n boolean isReactive = isUniBoolean(checkerMethod);\n if (!isReactive && !isPrimitiveBoolean(checkerMethod)) {\n throw new RuntimeException((\"@PermissionChecker method '%s' has return type '%s', but only \" +\n \"supported return types are 'boolean' and 'Uni'. \")\n .formatted(toString(checkerMethod), checkerMethod.returnType().name()));\n }\n\n var permissionName = annotationInstance.value().asString();\n if (permissionName.isBlank()) {\n throw new IllegalArgumentException(\n \"@PermissionChecker annotation placed on the '%s' attribute 'value' must not be blank\"\n .formatted(toString(checkerMethod)));\n }\n boolean isBlocking = checkerMethod.hasDeclaredAnnotation(BLOCKING);\n if (isBlocking && isReactive) {\n throw new IllegalArgumentException(\"\"\"\n @PermissionChecker annotation instance placed on the '%s' returns 'Uni' and is\n annotated with the @Blocking annotation; if you need to block, please return 'boolean'\n \"\"\".formatted(toString(checkerMethod)));\n }\n","sourceCodeStart":125,"sourceCodeEnd":161,"githubUrl":"https://github.com/quarkusio/quarkus/blob/e1c734241f34c7919086ceb4c9262b4a58f6de44/extensions/security/deployment/src/main/java/io/quarkus/security/deployment/PermissionSecurityChecks.java#L125-L161","documentation":"A @PermissionChecker method must return either a primitive boolean (synchronous check) or Uni (reactive check). Any other return type cannot be interpreted by the permission runtime, so the build fails with this message naming the actual type.","triggerScenarios":"Annotating a method whose return type is e.g. Boolean (boxed), Optional, CompletionStage, Uni with generics mismatch (isUniBoolean checks the exact type/signature), int, or void with @PermissionChecker.","commonSituations":"Returning boxed Boolean from a helper that previously could return null; migrating a synchronous checker to async and accidentally using CompletionStage instead of Uni; Kotlin developers returning Boolean? .","solutions":["Change the return type to primitive boolean for synchronous checks","Change the return type to Uni for reactive checks (SmallRye Mutiny)","If using CompletionStage, convert it: Uni.createFrom().completionStage(...)","If returning null/optional semantics, restructure to return boolean with explicit false"],"exampleFix":"// before\n@PermissionChecker(\"can-edit\")\nBoolean canEdit(Document doc) { return doc != null && doc.ownerId != null; }\n// after\n@PermissionChecker(\"can-edit\")\nboolean canEdit(Document doc) { return doc != null && doc.ownerId != null; }\n// reactive alternative\n@PermissionChecker(\"can-edit\")\nUni canEditAsync(Document doc) { return authService.can(doc.ownerId).map(o -> o != null); }","handlingStrategy":"validation","validationCode":"for (Method m : SecurityChecks.class.getDeclaredMethods()) {\n if (m.isAnnotationPresent(PermissionChecker.class)) {\n Class r = m.getReturnType();\n if (r != boolean.class && !io.smallrye.mutiny.Uni.class.equals(r)) {\n throw new IllegalStateException(\"@PermissionChecker \" + m.getName()\n + \" must return boolean or Uni, got: \" + r);\n }\n }\n}","typeGuard":"boolean hasValidCheckerReturnType(java.lang.reflect.Method m) {\n Class r = m.getReturnType();\n return r == boolean.class || io.smallrye.mutiny.Uni.class.equals(r);\n}","tryCatchPattern":"try {\n appBootstrap();\n} catch (RuntimeException e) {\n if (e.getMessage() != null && e.getMessage().contains(\"only supported return types are 'boolean' and 'Uni'\")) {\n throw new IllegalStateException(\"Change @PermissionChecker return type to boolean or Uni\", e);\n }\n throw e;\n}","preventionTips":["Use primitive boolean, never boxed Boolean/Optional","Use Uni (Mutiny), not CompletionStage, for async checks","Type-check @PermissionChecker methods in review and convention tests","Follow io.quarkus.security.PermissionChecker documentation examples"],"tags":["security","build-time","return-type","mutiny"],"backgroundTag":"invalid-permission-checker-return-type","analyzedSha":"e1c734241f34c7919086ceb4c9262b4a58f6de44","analyzedAt":"2026-09-05T17:01:29.979Z","contentChangedAt":"2026-09-05T17:01:29.979Z","schemaVersion":2},"datasetVersion":"2026-09-14T00:17:10.932Z"}