When using iota to create enums (constant sets), start from 1 and use 0 as a 'zero value' meaning undefined or default. This way, an uninitialized variable of that enum type will not accidentally hold a valid value.
In Go, an int's zero value is 0. If your enum uses 0 as a valid value, any variable of that enum type will default to that value even if never set, which can cause logic errors. Reserving 0 as an invalid or default state helps catch uninitialized usage.
Side-by-side examples engineers can pattern-match during review.
type Role int
const (
RoleUser Role = iota // 0
RoleAdmin // 1
)
var r Role
fmt.Println(r) // r is 0 -> interprets as RoleUser, even though we never set ittype Role int
const (
_ Role = iota // 0 is skipped/reserved
RoleUser // 1
RoleAdmin // 2
)
var r Role
fmt.Println(r) // r is 0, which we treat as an undefined defaulttype Role int
const (
RoleUser Role = iota // 0
RoleAdmin // 1
)
var r Role
fmt.Println(r) // r is 0 -> interprets as RoleUser, even though we never set ittype Role int
const (
_ Role = iota // 0 is skipped/reserved
RoleUser // 1
RoleAdmin // 2
)
var r Role
fmt.Println(r) // r is 0, which we treat as an undefined defaultFrom the same buckets as this rule.
Check if loops use equality operators (== or !=) in termination conditions. These can lead to infinite loops if the condition is never met exactly. Instead, use relational operators like < or > for safer loop termination.