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Cover image for Code Smell 166 - Low-Level Errors on User Interface
Maxi Contieri
Maxi Contieri

Posted on • Originally published at maximilianocontieri.com

2

Code Smell 166 - Low-Level Errors on User Interface

Fatal error: Uncaught Error: Class 'logs_queries_web' not found in /var/www/html/query-line.php:78 Stack trace: #0 {main} thrown in /var/www/html/query-line.php on line 718

TL;DR: Catch your errors. Even the ones you don't expect.

Problems

  • Security

  • Error Handling

  • Error Logging

  • Bad UX Experience

Solutions

  1. Use a top-level handler

  2. Avoid languages favoring return codes

  3. Expect database and low-level errors

Context

Even in 2022, we can see "serious" websites showing casual users a stack or debugging message.

Sample Code

Wrong


<?



Fatal error: Uncaught Error: Class 'MyClass' 

  not found in /nstest/src/Container.php:9

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Right


<?



// A user-defined exception handler function

function myException($exception) {

    logError($exception->description())

    // We don't show Exception to final users      

}



// Set user-defined exception handler function

set_exception_handler("myException");

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Detection

[X] Automatic

We can use mutation testing to simulate problems and see if they are handled correctly.

Tags

  • Security

Conclusion

We need to keep maturing.

Our solutions shouldn't be sloppy.

We need to improve our reputation as serious software engineers.

Relations

More Info

Disclaimer

Code Smells are just my opinion.

Credits

Photo by jesse orrico on Unsplash


80 percent of my problems are simple logic errors. 80 percent of the remaining problems are pointer errors. The remaining problems are hard.

Mark Donner


This article is part of the CodeSmell Series.

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