Go (Golang) is designed to be simple, fast, and readable, but even experienced programmers fall into recurring mistakes that harm correctness, performance, readability, or maintainability. The following editorial highlights 100 common Go mistakes, grouped by theme, with concise explanations, examples of the bad pattern, and concrete fixes. Use this as a checklist when writing, reviewing, or refactoring Go code.
Note: each numbered entry is a single mistake followed by the fix and a short illustrative example when helpful.
This section alone is worth the price of the book for backend engineers. 100 Go Mistakes And How To Avoid Them Pdf Download
Mistake: Using value.(Type) without the comma-ok idiom, causing a panic if the assertion fails.
Avoidance: Always use v, ok := value.(Type).
Returning a *struct that is nil inside an error interface results in err != nil being true. Go (Golang) is designed to be simple, fast,
| Category | Example Mistake | Fix |
|----------|----------------|-----|
| Slices | Not reusing slices properly | Use copy() or set slice to nil |
| Maps | Iterating and writing concurrently | Use sync.RWMutex or sync.Map |
| Goroutines | No cancellation signal | Use context or done channel |
| Errors | Swallowing errors | Always check and wrap errors |
| JSON | Embedding sync.Mutex with marshaling | Omit or isolate the field |
Beyond legal and security issues, an illegal PDF typically lacks: Mistake #79: Inefficient Slice Initialization
The book categorizes mistakes into several distinct areas. Below is a summary of the most critical sections you should focus on.
Mistake: Starting goroutines inside a loop that capture the loop variable.
for i := 0; i < 10; i++
go func()
fmt.Println(i) // All goroutines may print "10"
()
Avoidance: Pass the variable as a parameter or create a new copy inside the loop.