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go.regex_compile

Performance Medium

Detects regex patterns compiled repeatedly inside loops or frequently-called functions.

Why It Matters

Compiling regex in hot paths:

Wastes CPU — Regex compilation is expensive
Increases latency — Each request pays compilation cost
Scales poorly — Impact grows with traffic
Triggers GC pressure — Allocates memory repeatedly

Example

// ❌ Before (compiled every call)
func validateEmail(email string) bool {
    pattern := regexp.MustCompile(`^[\w.-]+@[\w.-]+\.\w+$`)
    return pattern.MatchString(email)
}

// ✅ After (compiled once)
var emailPattern = regexp.MustCompile(`^[\w.-]+@[\w.-]+\.\w+$`)

func validateEmail(email string) bool {
    return emailPattern.MatchString(email)
}

What Unfault Detects

regexp.Compile() inside functions
regexp.MustCompile() inside loops
Repeated pattern compilation in handlers

Auto-Fix

Unfault moves regex compilation to package level:

// Moved to package level
var _pattern = regexp.MustCompile(`\d{4}-\d{2}-\d{2}`)