The Turkish İ Problem and Why You Should Care

Well, this is our world 🙂

Take a look at the following code.

	const string input = "interesting";
	bool comparison = input.ToUpper() == "INTERESTING";
	Console.WriteLine("These things are equal: " + comparison);
	Console.ReadLine();

view raw Turkish.cpp hosted with ❤ by GitHub

Let’s imagine that input is actually user input or some value we get from an API. That’s going to print out These things are equal: True right? Right?!

Well not if you live in Turkey. Or more accurately, not if the current culture of your operating system is tr-TR (which is likely if you live in Turkey).

To prove this to ourselves, let’s force this application to run using the Turkish locale. Here’s the full source code for a console application that does this.

	using System;
	using System.Globalization;
	using System.Threading;
	internal class Program
	{
	private static void Main(string[] args)
	{
	Thread.CurrentThread.CurrentCulture = new CultureInfo("tr-TR");
	const string input = "interesting";
	bool comparison = input.ToUpper() == "INTERESTING";
	Console.WriteLine("These things are equal: " + comparison);
	Console.ReadLine();
	}
	}

view raw Turkish.java hosted with ❤ by GitHub

Now we’re seeing this print out These things are equal: False.

To understand why this is the case, I recommend reading much more detailed treatments of this topic:

• Internationalization for Turkish: Dotted and Dotless Letter “I”
• What’s Wrong With Turkey

The tl;dr summary summary is that the uppercase for i in English is I (note the lack of a dot) but in Turkish it’s dotted, İ. So while we have two i’s (upper and lower), they have four.

this detailed article is published on You’ve Been Haacked, please click for the full version