Golang prohibits ignoring errors

Why golang prohibits ignoring errors

During the development process of golang, ignoring errors may be a tempting practice, but unfortunately, it can also be a very dangerous practice. Therefore, golang strongly prohibits ignoring errors in code. In this article, we will discuss why golang prohibits ignoring errors and how to follow this rule in your code.

Error handling is an important aspect of any programmer's work, and it is even more inevitable for golang. Simply put, error handling refers to the processing that needs to be done when an abnormal situation is encountered during program execution. These exceptions can be some runtime errors, such as file reading failure, network connection interruption, etc. For these exceptions, we hope that the program can detect and handle them in time. If it cannot be handled, it should report it to the upper-level program or terminate the program directly.

In golang, most functions will return an error value. These error values ​​can help us determine whether the function call is successful. Typically, we need to handle these errors explicitly on every execution path of our code. For example:

f, err := os.Open("file.txt")
if err != nil {
    // 处理错误
}

// 使用f

In the above code, we first try to open a file, and if the file is opened successfully, the returned file can be used. Otherwise, we need to handle the error in the if statement. This approach ensures that we handle errors promptly and provides a clear path for errors.

If you use some of golang's advanced tools, such as go vet and staticcheck, you may get warnings when ignoring errors in your code. The following is the result of go vet finding an error in the example code:

$ go vet main.go
# command-line-arguments
./main.go:5:3: error return value not checked (fmt.Sprintf("error: %s", err))

This warning means that we ignored the error somewhere in the code. Ignoring this warning while developing may seem simple, but it is actually very dangerous. If we ignore errors eventually it will lead to potential problems in the code such as bad runtime behavior and program crashes.

Solution

So, how to effectively follow golang’s error handling rules?

First of all, we should learn to use some predefined functions to handle errors, such as panic, log, fmt, etc. When actually writing business code, we should use these functions as much as possible to record and handle errors. For example:

f, err := os.Open("file.txt")
if err != nil {
    log.Fatalf("error opening file: %s", err)
}

// 使用f

In the above code, we use the log.Fatalf function to record errors. This method not only prints out error information when the program crashes, but also provides a clear processing path to ensure that we can handle errors in time.

In addition, if we are sure that an error will not affect program execution, we can use the "_" symbol to ignore these error values. But this situation should be avoided as much as possible.

_, err := fmt.Println("Hello, world!")
if err != nil {
    log.Fatalf("error printing string: %s", err)
}

In the above code, we used the "_" symbol to ignore the error value of the Println function. This approach allows us to log error information, but also indicates that we are ignoring the error value, which is also a bad habit.

Conclusion

In golang, we should always remember that ignoring errors can be a very dangerous practice. Therefore, we should follow golang's error handling rules in the code and use predefined functions to handle errors to ensure that we can always detect and handle errors in a timely manner in the program.

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