Go: What is the difference between panic and error?

panic — crash. error — expected.

1panic("crash")
2
3func Read() ([]byte, error) {
4    return os.ReadFile("file")
5}

When to use panic:

• init() failures.
• Unrecoverable conditions.

When to use error:

• Library functions.
• I/O operations.

Common mistakes:

• Using panic for normal errors.
• Ignoring errors.
• Panicking in library code.
• Not using errors.Is/errors.As.
• Using log.Fatal instead of error.