Why PHP Errors Matter

PHP errors provide critical insights into what’s breaking inside an application. Yet many developers turn them off in production without understanding how to use them properly during development.

The Four Main Types of PHP Errors

• Notice: Minor issues like undefined variables, often harmless but indicate weak logic.
• Warning: Something didn’t work as expected, but code keeps running.
• Fatal error: Code execution stops immediately because a function or class is missing.
• Parse error: Syntax mistake — PHP can’t even start processing the file.

Enable Error Reporting in Development

You should always turn on full debugging while building a site:

error_reporting(E_ALL);
ini_set("display_errors", 1);

On production sites, hide errors from users and log them instead:

ini_set("display_errors", 0);
ini_set("log_errors", 1);
ini_set("error_log", __DIR__ . "/php-error.log");

Reading a PHP Error Message

A typical message gives you a lot of information:

Fatal error: Uncaught Error: Call to undefined function foo() in /var/www/html/index.php on line 12

• Error Type: Fatal
• Cause: Undefined function foo()
• File: index.php
• Line: 12 — where debugging starts

Debugging With Xdebug

For complex applications, Xdebug is a game changer:

xdebug.mode = debug
xdebug.start_with_request = yes

It allows breakpoints, stack tracing and step-by-step execution from your IDE.

Common PHP Error Causes & Fixing Techniques

• Undefined variables: Check variable names and scope.
• Missing includes: Use require_once for critical files.
• Wrong permissions: Ensure PHP can read/write necessary paths.
• Deprecated functions: Upgrade codebase to match PHP version.

Pro Debugging Tips

• Use var_dump() or print_r() to inspect exact data structures.
• Log what you can’t display — logs tell the truth after errors occur.
• Break big problems into small, reproducible test cases.
• Fix the first error — others may simply be cascading failures.

Final Thought

PHP isn’t trying to annoy you — it’s trying to tell you what’s wrong. Learn to read error messages clearly, and you’ll solve bugs faster, build more reliable code and feel confident shipping features.