Function update

internal/godebug/godebug.go:177–196

update records an updated GODEBUG setting. def is the default GODEBUG setting for the running binary, and env is the current value of the $GODEBUG environment variable.

(def, env string)

// def is the default GODEBUG setting for the running binary,
// and env is the current value of the $GODEBUG environment variable.
func update(def, env string) {
	updateMu.Lock()
	defer updateMu.Unlock()

	// Update all the cached values, creating new ones as needed.
	// We parse the environment variable first, so that any settings it has
	// are already locked in place (did[name] = true) before we consider
	// the defaults.
	did := make(map[string]bool)
	parse(did, env)
	parse(did, def)

	// Clear any cached values that are no longer present.
	cache.Range(func(name, s any) bool {
		if !did[name.(string)] {
			s.(*setting).value.Store(&empty)
		}
		return true
	})
}

// parse parses the GODEBUG setting string s,
// which has the form k=v,k2=v2,k3=v3.