Reading and sharing a TYPO3 error page

When TYPO3 runs into an error it cannot handle, it replaces the page or the backend module with an error page. Which error page you get depends on the configuration:

On your local development installation, you see the detailed error page described below.
On a production server, visitors see a short page titled Oops, an error occurred! without any details, so that they learn nothing about the inner workings of the site. The details are written to the log, which you can read in the backend module Administration > Log.

The option displayErrors decides between the two pages. With its default value, only requests from an IP address listed in devIPmask get the detailed one.

The detailed error page

New in version 14.2 Feature: #106153 - Improve DebugExceptionHandler with copy functionality

The detailed error page shows the error message and its stack trace: the chain of PHP files and lines that led to the error. It is what you need when you ask for help, in a bug report or in a support channel. Send it as text rather than as a screenshot, which usually cuts the trace off.

Error page with the heading "Whoops, looks like something went wrong.", the buttons Toggle details and Copy plaintext stack trace in its header, and a Copy path button beside the first file of the trace — The header and the first trace entry of the detailed error page

The page offers three buttons:

Toggle details: Hides the file contents of every trace entry and brings them back, which turns the trace into a short overview.
Copy plaintext stack trace: Copies the whole trace as text, without the file contents. This is the text to paste into a bug report or a request for help.
Copy path: Sits beside every file in the trace and copies that file and its line as path/to/File.php:42, without the path of your project in front, so that you can paste it into your editor or IDE to open the file.

Before you pass the copied trace on, read through it and remove anything sensitive, such as passwords, keys or personal data. The page reminds you of this at the end of the trace.

Note

Copying to the clipboard needs a secure connection. If your site runs on http:// instead of https://, a browser such as Firefox refuses to copy, and the buttons report that they could not copy. Copy plaintext stack trace then writes the text into a box on the page, already selected, so that you can copy it by hand.

If the exception has a code, the box Get help in the TYPO3 Documentation links to the page about that code in the TYPO3 exceptions reference, where the community collects solutions.