{"record":{"id":"0f58073e3292a184","repo":"phalcon/cphalcon","slug":"invalid-definition-for-user-function-name-in","errorCode":null,"errorMessage":"Invalid definition for user function '{name}' in {file} on line {line}","messagePattern":"Invalid definition for user function '(.+?)' in (.+?) on line (.+?)","errorType":"exception","errorClass":"InvalidUserFunctionDefinition","httpStatus":null,"severity":"error","filePath":"phalcon/Mvc/View/Engine/Volt/Compiler.zep","lineNumber":1847,"sourceCode":"                     */\n                    if typeof definition == \"string\" {\n                        return definition . \"(\" . arguments . \")\";\n                    }\n\n                    /**\n                     * Execute the function closure returning the compiled\n                     * definition\n                     */\n                    if typeof definition == \"object\" {\n                        if definition instanceof Closure {\n                            return call_user_func_array(\n                                definition,\n                                [arguments, funcArguments]\n                            );\n                        }\n                    }\n\n                    throw new InvalidUserFunctionDefinition((string) name, (string) expr[\"file\"], (int) expr[\"line\"]);\n                }\n            }\n\n            /**\n             * This function includes the previous rendering stage\n             */\n            if name == \"get_content\" || name == \"content\" {\n                return \"$this->getContent()\";\n            }\n\n            /**\n             * This function includes views of volt or others template engines\n             * dynamically\n             */\n            if name == \"partial\" {\n                return \"$this->partial(\" . arguments . \")\";\n            }\n","sourceCodeStart":1829,"sourceCodeEnd":1865,"githubUrl":"https://github.com/phalcon/cphalcon/blob/b7419de9cd0a8a3f48441ead84c9f8415d463e25/phalcon/Mvc/View/Engine/Volt/Compiler.zep#L1829-L1865","documentation":"The Volt template compiler throws this when a template calls a user-registered function whose definition is not usable. In Compiler.zep:1847 a definition registered via Compiler::addFunction() is only accepted if it is a string (macro) or a Closure (invoked with the resolved arguments); any other value (array callable, integer, plain object) reaches the throw. The message carries the function name and the exact template file/line that invoked it. It surfaces at compile time, i.e. the first time the template is rendered (or when the compiled cache is cold).","triggerScenarios":"Calling $compiler->addFunction('myFunc', ['MyClass','myMethod']) (PHP array-style callable), or addFunction('myFunc', 123), then using {{ myFunc(x) }} in a .volt template. Also passing a plain object that is not a Closure, or a definition that was coerced to the wrong type by config loading.","commonSituations":"Developers porting plain PHP helpers to Volt register them with array callables ['Str', 'method'] or 'Class::method' with 'new' syntax, both rejected. Definitions pulled from a config file or container service can arrive as non-Closure objects. The error only fires when the template is actually compiled, so a bad registration can pass tests that never render that template.","solutions":["Change the definition to a Closure: $compiler->addFunction('myFunc', function ($resolvedArgs) { return 'my_php_func(' . $resolvedArgs . ')'; }) — the Closure must return a string of PHP code, not a value","Or use the string macro form if it maps 1:1 to a PHP function: $compiler->addFunction('myFunc', 'my_php_func')","If you wanted runtime logic, keep the Closure but return a valid PHP expression string that the compiled template will evaluate","Register functions in a shared 'volt' service via the DI container so every view uses the same registrations"],"exampleFix":"// before\n$voltCompiler->addFunction('highlight', ['Util', 'highlight']);\n{{ highlight(title) }}\n\n// after\n$voltCompiler->addFunction(\n    'highlight',\n    function ($resolvedArgs) {\n        return 'Util::highlight(' . $resolvedArgs . ')';\n    }\n);","handlingStrategy":"validation","validationCode":"$ok = is_string($definition) || $definition instanceof \\Closure;\nif (!$ok) {\n    throw new \\InvalidArgumentException(\n        'Volt function definitions must be a string or Closure, got '\n        . gettype($definition)\n    );\n}\n$compiler->addFunction('myFunc', $definition);","typeGuard":"function isVoltCallableDefinition($definition): bool\n{\n    return is_string($definition) || $definition instanceof \\Closure;\n}","tryCatchPattern":"try {\n    $view->render('page/index', $params);\n} catch (\\Phalcon\\Mvc\\View\\Engine\\Volt\\Exception $e) {\n    // message includes the template file/line of the failing call\n    $logger->error('Volt compile failed: ' . $e->getMessage());\n    echo 'Template temporarily unavailable.';\n}","preventionTips":["Keep all addFunction registrations in one dedicated volt service so definitions are reviewed in a single place","Write a tiny registration helper that asserts is_string/\\Closure and throws early with the function name","Add a smoke test that renders a template exercising every registered function so bad definitions fail in CI, not production"],"tags":["phalcon","volt","template-compiler","user-function","callback"],"backgroundTag":"invalid-callback-definition","analyzedSha":"b7419de9cd0a8a3f48441ead84c9f8415d463e25","analyzedAt":"2026-08-21T06:21:18.811Z","schemaVersion":2},"datasetVersion":"2026-08-21T11:28:35.574Z"}