go-defensive

Preventing internal state mutation requires boundary copying in Go, duplicating slices and maps on input or output when ownership should not be shared. This stops callers from modifying your package's internal data.

Handling time testably in Go APIs requires using time.Time, time.Duration, and injected clocks. This approach allows tests to control time precisely, ensuring your exported business logic remains deterministic and robust.

Avoiding accidental panic propagation in Go library interfaces requires returning errors safely instead of panicking. You must also enforce cleanup discipline by placing defer statements immediately after resource acquisition like locks or files.

Using crypto/rand for secret material in Go prevents weak randomness vulnerabilities. Unlike math/rand, crypto/rand provides cryptographically secure random numbers, which is a required safety check for hardening exported API boundaries.

Enforcing compile-time interface compliance in Go requires adding compile-time interface checks to your exported functions and methods. This verifies that types satisfy contracts before runtime, preventing ambiguous zero-value enums and leaks.

Yes, this defensive programming approach works for existing Go packages by reviewing exported APIs to avoid mutable globals. It hardens library interfaces by requiring boundary copying, injected clocks, and invalid zero-value enums for safer state.