Dynamic property deprecated PHP Origin: Application & API Last updated 13 Oct 2026

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

PHP 8.2+ deprecates creating properties that aren’t declared in the class.

Exact message you may see Creation of dynamic propertyis deprecated
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Seen on: PHP

Meaning

Assigning $this->bar = … without declaring bar used to silently create it. PHP 8.2 deprecates this to catch typos; PHP 9 is expected to make it an error.

Common causes

  • Old code relying on dynamic properties
  • Typos in property names
  • Libraries not yet updated for PHP 8.2

⚡ Quick fix

  1. Declare the property in the class
  2. Add #[\AllowDynamicProperties] to classes that truly need it
  3. Update libraries

Detailed fix by platform

PHP

  1. class Foo { public ?string $bar = null; }

How to diagnose

  1. Class — Which class and property?
  2. Origin — Your code or a library?

🔧 Still not fixed?

Many errors look alike. If the steps above didn’t solve it, one of these is probably what you’re facing:

Where this error sits

Origin: Application & API. Errors that are often confused with or caused by this one (click to open):

Call to undefined function create_function() — WordPress on PHP 8: Fatal error: Uncaught Error: Call to undefined function create_function() / each() (WordPress)Call to undefined fun…componentWillMount renamed — Warning: componentWillMount has been renamed, and is not recommended for use. (React)componentWillMount re…config global deprecated — npm WARN config global `--global`, `--local` are deprecated. Use `--location=global` instead. (npm)config global depreca…DEP0005 — DeprecationWarning: Buffer() is deprecated due to security and usability issues (DEP0005) (Node.js)DEP0005DEP0040 — DeprecationWarning: The `punycode` module is deprecated (DEP0040) (Node.js)DEP0040Deprecated null to internal — Deprecated: strlen(): Passing null to parameter #1 ($string) of type string is deprecated (PHP)Deprecated null to in…Implicit float to int — Deprecated: Implicit conversion from float 2.5 to int loses precision (PHP)Implicit float to intnpm WARN deprecated — npm WARN deprecated package@1.2.3: This package is no longer supported. (npm)npm WARN deprecatedDynamic p…

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