𝟭𝟬 𝗣𝗛𝗣 𝗕𝘂𝗴𝘀 𝗧𝗵𝗮𝘁 𝗕𝗿𝗲𝗮𝗸 𝗥𝗲𝗮𝗹 𝗣𝗿𝗼𝗷𝗲𝗰𝘁𝘀

𝟭𝟬 𝗣𝗛𝗣 𝗕𝘂𝗴𝘀 𝗧𝗵𝗮𝘁 𝗕𝗿𝗲𝗮𝗸 𝗥𝗲𝗮𝗹 𝗣𝗿𝗼𝗷𝗲𝗰𝘁𝘀

Code works on your computer. You push it to the server. Everything breaks. There are no errors in the logs. You just see the wrong output.

These bugs do not come from textbooks. They come from real login systems, stores, and APIs. They look fine during code reviews but fail in production.

Here are bugs #11 through #20 and how to fix them.

• Infinite Loops Forgetting to increment a counter locks the PHP process. This can crash your entire server. Fix: Always ensure your loop counters increase.

• Case-Sensitivity Issues PHP sees "Admin" and "admin" as different strings. This breaks access control. Fix: Use strtolower() before you compare strings.

• Math and Truncation Using (int) on a decimal does not round it. It cuts it off. This causes financial errors in billing. Fix: Use round() or number_format().

• JSON Errors json_decode returns an object by default. If you try to use it like an array, the script fails. Fix: Pass true as the second argument to get an array.

• XSS Security Risks Printing user input directly allows attackers to inject scripts. Fix: Always use htmlspecialchars().

• Path Failures Relative paths work on local machines but fail on live servers. Fix: Use the DIR constant for absolute paths.

• Duplicate Data Users often double-click submit buttons. This creates duplicate database entries. Fix: Check if the record exists first and use a UNIQUE constraint in your database.

• Merging Arrays array_merge() resets numeric keys to zero. This destroys your data structure. Fix: Use the + operator or array_replace() to keep your keys.

• Invisible Errors Turning off errors in production is good for security. It is bad for debugging if you do not log them. Fix: Set log_errors to 1 and define an error_log path.

• Loop References A foreach loop modifies a copy of the data, not the original array. Fix: Use the & symbol to create a reference, but always unset the variable after the loop.

Most of these bugs do not throw errors. PHP keeps running, but it produces the wrong results. This makes them dangerous.

Writing code is easy. Writing production-ready code requires understanding how things fail.

Read the full guide here: https://dev.to/bikkisingh/10-php-bugs-that-break-real-projects-and-how-to-fix-them-part-2-7hm