Fix Cannot assign to property of type in PHP
What does the message mean?
Which PHP version does your site report?
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More about this
Cannot assign ... to property ... of type ... means code is trying to store a value that does not fit a typed property.
Keep the class, property and both types from the message.
This is an assignment failure, not an attempt to read an uninitialized property.
Those two problems need different investigations and different repairs.
Before you start
Save the complete error line and its timestamp in a private note. Record the action that failed, the current PHP versionA PHP version is a numbered edition of PHP, like 8.3. Each edition is looked after for a limited time, then gets security fixes only, then nothing. and any components updated at the same time. Share only information needed for the investigation.
Public support forums are not suitable places for customer details, access credentials or complete server paths.
Back up both files and the database before making changes. Check that the backupA backup is a separate copy of your website's files and database, so you can bring the site back after a mistake, a hack or a failed update. is usable. Work on a restricted test copy with the same PHP version and relevant settings.
Disable real payments and outgoing customer emails there. Agree who will make the change and who will check the result. These steps are an investigation guide, not a diagnosis of your particular website.
Versions and responsibility
Ask your administrator to confirm the PHP version serving the affected website. Also record the WordPressWordPress is free software for building and editing a website in your browser. It is written in PHP, so it builds each page when someone visits., themeA WordPress theme is a ready-made package that decides how your WordPress site looks and how its pages are laid out. Change the theme and the design changes., pluginA WordPress plugin is an add-on you install in WordPress to give your site extra features, such as contact forms, SEO tools or a webshop. and bundled library versions involved. Establish which components changed during the same maintenance session.
A test using different code can give a different result even when its PHP version matches. Agree beforehand which user action will demonstrate a successful repair. Assign one responsible person to follow both the change and its acceptance check.
On the test copy, verify that scheduled jobs, payments and messages are actually separated from the live website.
Causes and PHP version
Typed properties have existed since PHPPHP is a programming language that builds your web pages on the computer that hosts your site, just before they reach the visitor. WordPress runs on it. 7.4, so this message is not exclusive to PHP 8. A simultaneous plugin update may introduce stricter data contracts that older settings do not satisfy. Investigate both the code change and the value origin.
Text from a form, an old database value and an integration object can each require different validation.
Choosing the correct repair
Ask the maintainer to normalize valid input at the application boundary. This means controlled conversion according to the data contract. Invalid input needs a clear rejection.
Do not remove the type just to bypass the failure or blindly convert unknown text into a number. An invalid setting could otherwise become an accepted but incorrect value.
Five steps to a repair
- Record the property rejecting the value and the required type. Save the failed user action without publishing confidential field contents or private records.
- Trace the assigned value to a form, saved setting or integration. Compare older records with newly submitted values on the test copy.
- Establish which conversion is meaningful for the application. Keep missing required data distinguishable and reject invalid input before assigning it to the property.
- Test valid input, empty input and a value of the wrong type. Include reopening settings already stored before the code change.
- Repeat saving and reading through the ordinary user flow. Compare the final value with the original intention and inspect new log entries.
A practical check
A plugin setting for the number of available places provides an acceptance example. Test a valid number, an empty required field and invalid text. The valid number must save correctly; the other cases should show the agreed validation message.
Then reopen a previously saved setting. This checks new input and existing records without accepting an arbitrary default value as a repair.
Getting help and checking the repair
Use the help form below if you cannot access the logs or do not know who maintains the affected code. Describe one failed action and the expected result. Ask for a proposal that separates the cause, the change and the acceptance check.
Do not include passwords with your request.
After the repair, repeat the original action on the test copy. Also check a normal visitor journey, an empty result and invalid input where relevant. Review fresh log entries at the new test time.
Keep versions and outcomes in your maintenance notes. Let the responsible administrator decide when the tested change can be applied to the live website.
Choosing the next step
Use the links below this article to choose the next step. The PHP update page helps you discuss maintenance with the administrator. Use the Exposure Check to check your PHP version.
Not every server exposes its version; confirm missing information with your host. This is a separate public check; do not treat its result as evidence that this programming error is repaired. Use the status page for current security information.
Keep the repair of the visitor action and the assessment of the server as separate checks in your notes. When requesting help, include the error text, the failed action and the expected result, but no passwords. Ask for one responsible person to oversee both the change and its acceptance.