PHP New Added 29 September 2026

PHP 8.2: Deprecated: Creation of dynamic property Foo::$bar is deprecated

Since PHP 8.2, assigning to a property that the class never declared raises a deprecation, and it is scheduled to become an error. Older code relied on setting arbitrary properties on objects, so an upgrade floods the log with these even though nothing has visibly broken. The fix is to declare the property, not to suppress the notice.

Quick fix

Read the commands before running them. Anything that restarts a service, deletes data or changes permissions should be tried on a non-production system first.

Quick fix

<?php
// Fix 1: declare the property
class Foo {
    public ?string $bar = null;
}

// Fix 2: a class that genuinely needs arbitrary properties can opt in
#[\AllowDynamicProperties]
class LegacyRecord {}

// stdClass and classes with __get/__set are not affected

# Find every occurrence before it becomes an error
php -d error_reporting=E_ALL -d display_errors=1 vendor/bin/phpunit 2>&1 | grep 'dynamic property' | sort | uniq -c

# Or let a tool rewrite them
# vendor/bin/rector process src   (with the PHP 8.2 set)

How to diagnose PHP errors

PHP errors are dominated by per-request resource limits (memory_limit, max_execution_time) and by autoloading. Class-not-found errors are almost never missing code. They are a namespace that does not match the PSR-4 mapping, or a stale Composer autoload map. Laravel adds a caching layer that produces genuinely confusing errors when configuration is cached with the wrong environment.

If the quick fix above does not resolve it, work through these steps. They apply to this whole class of error, not just to this one message, which is usually what saves the time.

Read the real limits from the running process, not from a config file: php -i | grep -E 'memory_limit|max_execution_time'. CLI and FPM have separate configurations.
Regenerate the autoload map with composer dump-autoload -o before investigating a class-not-found error any further.
For Laravel, clear cached config and routes with php artisan optimize:clear. A config cache built in the wrong environment causes errors that survive every code change.
Enable full error display in development (display_errors=On, error_reporting=E_ALL). The default production settings hide the cause.
For PDO connection refusals, test the same credentials with the database's own CLI client to separate PHP configuration from database access.

Tools worth reaching for

php -i
composer dump-autoload -o
php artisan optimize:clear
Xdebug
tail -f storage/logs/laravel.log

Authoritative references

Primary documentation for this error, worth reading before applying any fix in production.

php.net php.net

Related PHP errors

See all 20 PHP errors →

Browse other categories

Something missing or wrong?

This entry is maintained by hand. If the fix is out of date, incomplete, or you have a better one, email a correction and it will be reviewed.