---
title: "How to debug PHP errors in a snippet - Code Snippets"
description: "Where to find the error when a PHP snippet fails in Joomla, what gets a snippet auto-disabled, the mistakes you'll meet most often, and how to fix each one."
url: "https://www.tassos.gr/docs/code-snippets/troubleshooting/debug-php-errors"
date: "2026-10-22T23:03:17+00:00"
language: "en-GB"
---

[ Home ](https://www.tassos.gr/docs) / [ Code Snippets ](https://www.tassos.gr/docs/code-snippets) / [ Troubleshooting ](https://www.tassos.gr/docs/code-snippets/troubleshooting)

#  How to debug PHP errors in a snippet

##  Where to find the error when a PHP snippet fails in Joomla, what gets a snippet auto-disabled, the mistakes you'll meet most often, and how to fix each one.

When a PHP snippet fails, Code Snippets disables it and keeps the error for you. This article shows where to find it, what the common errors mean, and how to see the ones that don't disable the snippet.

## [Where the error shows up](#where-the-error-shows-up)

- **The snippets list.** The failed snippet's status reads **Auto-Disabled**, and the Status filter has an entry for it.
- **The edit screen.** Open the snippet. The error message, the stack trace and the error date sit at the top.
- **The Error Logs page.** Click **Error Logs** in the toolbar of the snippets list. Each snippet gets its own log file under `administrator/logs/tassos_code_snippets/`, and the page lets you read and clear them.
- **Your inbox.** The site's administrator email address receives the error details.

The log file and the email are on by default. Turn them off in the component's **Options**, under **Log Errors** and **Notify Admin**.

## [What disables a snippet, and what doesn't](#what-disables-a-snippet-and-what-doesn-t)

Any exception or error the snippet throws disables it. Since version 1.0.2 so does a fatal error PHP can't throw: a function or class declared twice, exhausted memory, or the execution time limit. The snippet goes to Auto-Disabled and the next request works.

Two cases leave the snippet published. A plain `exit()` or `die()` ends the request without an error. A loop that only waits (a `sleep()`, a slow HTTP call) never reaches PHP's time limit on Linux, so it hangs instead. For both, [safe mode](https://www.tassos.gr/docs/code-snippets/troubleshooting/safe-mode) pauses every snippet so you can get in and fix it.

## [Common errors and their fixes](#common-errors-and-their-fixes)

### [Call to undefined function, or class not found](#call-to-undefined-function-or-class-not-found)

A Joomla class is used without its namespace. Add a `use` line at the top of the snippet, for example `use Joomla\CMS\Factory;`, or write the full name: `\Joomla\CMS\Factory::getApplication()`.

### [Cannot redeclare function](#cannot-redeclare-function)

Two published snippets declare the same function, so the second one fails and gets disabled. Keep shared functions in one snippet, give the others a prefix, or guard the declaration:

 ```
if (!function_exists('my_helper'))
{
    function my_helper()
    {
        // ...
    }
}
```

### [Maximum execution time exceeded](#maximum-execution-time-exceeded)

A loop that never ends, or one that waits on a slow service on every request. Check the loop's exit condition, and keep slow HTTP calls behind a condition or a cache so they don't run on every page.

## [Seeing warnings and notices](#seeing-warnings-and-notices)

Warnings, notices and deprecations don't disable the snippet and don't reach the log. To see them, set **Error Reporting** to **Maximum** under **System** → **Global Configuration** → **Server**, on a staging site. They then print on the page.

## [Debugging without a debugger](#debugging-without-a-debugger)

Queue a message to prove a line is reached, or to look at a value. It shows in Joomla's message area on the site and in the administrator:

 ```
use Joomla\CMS\Factory;

$app = Factory::getApplication();
$app->enqueueMessage('Reached line 12, user id ' . $app->getIdentity()->id, 'notice');
```

For values you want to keep, write them to a log file in `administrator/logs`:

 ```
use Joomla\CMS\Log\Log;

Log::addLogger(['text_file' => 'my-snippet.php'], Log::ALL, ['my-snippet']);
Log::add('Reached line 12', Log::INFO, 'my-snippet');
```

When several snippets interact, unpublish all but one and add them back one at a time.

## [Re-enable the snippet](#re-enable-the-snippet)

Fix the code, set **Status** back to **Published** and save. Saving a published snippet clears the stored error and its date.

If the snippet runs but nothing happens, [Why your PHP snippet isn't running](https://www.tassos.gr/docs/code-snippets/troubleshooting/php-snippets-not-running) has the checklist. The [PHP snippet docs](https://www.tassos.gr/docs/code-snippets/types/php) cover the events, the document type check and the blocked functions.

 Last updated on Oct 19th 2026 10:10