Recent versions of go contains for loop changes. Lets see how they differ from the previous versions.
In Go 1.22, there are significant changes to the for loop functionality. This has been widely discussed as it addresses one of the most common Go mistakes developers encounter.
In Go, the loop iterator variable is a single variable that takes different values in each iteration. While this is efficient, it can lead to unexpected behavior when used incorrectly. Using goplay.tools (considered one of the best Go playgrounds available), we can demonstrate this issue.
When running the code in Go 1.21, even though we loop through numbers one through eight, the output shows eight repeated five times. The traditional fix for this involves explicitly passing the value into the function. When implemented correctly, it prints all values as expected.
This issue in Go 1.21 and earlier versions stems from scope behavior. Importantly, there are no error messages - it's valid Go code. Unless you have excellent test coverage, this issue could easily be missed. This is particularly problematic with goroutines, which are notoriously difficult to test.
A future video will discuss GoVet and how it can help catch these types of issues.
In Go 1.22, the same example works differently. You no longer need to pass the value into the Go function explicitly. Running the code produces the correct behavior automatically, similar to when you explicitly passed the value in previous versions. This change will help many developers avoid this common error.
Another significant addition in Go 1.22 is the ability to range over loops in a new way. This wasn't available in Go 1.21, where you'd need to create an array and loop over it. This new syntax is more succinct, addressing criticism about Go's verbosity. It aligns better with other programming languages and should make things easier for developers new to Go.
Both of these changes to the for loop functionality in Go 1.22 are considered excellent improvements that will enhance the development experience and help prevent common mistakes. These are highly positive changes that the speaker will certainly be using, and encourages others to use as well.
