I am getting undefined constant CURL_IPRESOLVE_V4 in my Laravel 10 project

[petethewizard]

I noticed this in my Laravel logs. I am using Laravel 10. rollbar-laravel 8.13.

Here is the full stack trace:

[2025-07-31 19:03:06] local.ERROR: Undefined constant "Rollbar\Senders\CURL_IPRESOLVE_V4" {"exception":"[object] (Error(code: 0): Undefined constant \"Rollbar\\Senders\\CURL_IPRESOLVE_V4\" at /var/www/iot-center.de/vendor/rollbar/rollbar/src/Config.php:769) [stacktrace] #0 /var/www/iot-center.de/vendor/rollbar/rollbar/src/Config.php(501): Rollbar\\Config->setupWithOptions() #1 /var/www/iot-center.de/vendor/rollbar/rollbar/src/Config.php(301): Rollbar\\Config->setSender() #2 /var/www/iot-center.de/vendor/rollbar/rollbar/src/Config.php(242): Rollbar\\Config->updateConfig() #3 /var/www/iot-center.de/vendor/rollbar/rollbar/src/RollbarLogger.php(52): Rollbar\\Config->__construct() #4 /var/www/iot-center.de/vendor/rollbar/rollbar/src/Rollbar.php(142): Rollbar\\RollbarLogger->__construct() #5 /var/www/iot-center.de/vendor/rollbar/rollbar/src/Rollbar.php(99): Rollbar\\Rollbar::setLogger() #6 /var/www/iot-center.de/vendor/rollbar/rollbar-laravel/src/RollbarServiceProvider.php(36): Rollbar\\Rollbar::init() #7 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Container/Container.php(908): Rollbar\\Laravel\\RollbarServiceProvider->{closure:Rollbar\\Laravel\\RollbarServiceProvider::register():30}() #8 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Container/Container.php(795): Illuminate\\Container\\Container->build() #9 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Foundation/Application.php(986): Illuminate\\Container\\Container->resolve() #10 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Container/Container.php(731): Illuminate\\Foundation\\Application->resolve() #11 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Foundation/Application.php(971): Illuminate\\Container\\Container->make() #12 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Foundation/helpers.php(120): Illuminate\\Foundation\\Application->make() #13 /var/www/iot-center.de/vendor/rollbar/rollbar-laravel/src/RollbarServiceProvider.php(68): app() #14 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(36): Rollbar\\Laravel\\RollbarServiceProvider->boot() #15 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Container/Util.php(41): Illuminate\\Container\\BoundMethod::{closure:Illuminate\\Container\\BoundMethod::call():35}() #16 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(93): Illuminate\\Container\\Util::unwrapIfClosure() #17 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(35): Illuminate\\Container\\BoundMethod::callBoundMethod() #18 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Container/Container.php(662): Illuminate\\Container\\BoundMethod::call() #19 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Foundation/Application.php(1059): Illuminate\\Container\\Container->call() #20 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Foundation/Application.php(1040): Illuminate\\Foundation\\Application->bootProvider() #21 [internal function]: Illuminate\\Foundation\\Application->{closure:Illuminate\\Foundation\\Application::boot():1039}() #22 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Foundation/Application.php(1039): array_walk() #23 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/BootProviders.php(17): Illuminate\\Foundation\\Application->boot() #24 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Foundation/Application.php(286): Illuminate\\Foundation\\Bootstrap\\BootProviders->bootstrap() #25 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php(447): Illuminate\\Foundation\\Application->bootstrapWith() #26 /var/www/iot-center.de/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php(199): Illuminate\\Foundation\\Console\\Kernel->bootstrap() #27 Command line code(1): Illuminate\\Foundation\\Console\\Kernel->handle() #28 {main} "}

Curl 7.88 is installed. Any ideas?

[linear]

SDK-526 I am getting undefined constant CURL_IPRESOLVE_V4 in my Laravel 10 project

[danielmorell]

I would make sure the cURL PHP extension is enabled in your php.ini file. There should be a line that looks something like this:

extension=curl.so

If it is missing or commented out with a semicolon ;, you will need to fix that.

The name resolution rules for constants should check the global scope for the constant. If it it does not exist in the namespace and also does not exist in the global scope it will throw an error specifying the missing constant as a member of the current namespace.

This is why the missing constant is identified as Rollbar\Senders\CURL_IPRESOLVE_V4 even though the fully qualified name of the constant we are looking for is \CURL_IPRESOLVE_V4.

[petethewizard]

I used phpinfo(); to check whether curl was enabled, and it is. Also, I ran code to check if the constant is defined, and it is defined (outside of Laravel, though, I will check in Laravel too).

[danielmorell]

Are you getting the error locally or just in your production environment?

If you are getting the error locally, an interesting test would be to edit the /vendor/rollbar/rollbar/src/Senders/CurlSender.php by adding a \ before each of the CURL... constants in the file. For example, CURL_IPRESOLVE_V4 would become \CURL_IPRESOLVE_V4. This would force the name resolution to only look in the global namespace and not to look in the current namespace.

If you start getting Undefined constant "CURL_IPRESOLVE_V4" errors without the namespace, that would indicate that the PHP extension is not being loaded for some reason.

On the other hand, if the errors go away, it would indicate that PHP is not following the expected constant name resolution procedure. This would be unexpected, since I don't believe there is any way to adjust how PHP does name resolution.