kubernetes/vendor/golang.org/x/tools/go/packages/visit.go

// Visit visits all the packages in the import graph whose roots are
// pkgs, calling the optional pre function the first time each package
// is encountered (preorder), and the optional post function after a
// package's dependencies have been visited (postorder).
// The boolean result of pre(pkg) determines whether
// the imports of package pkg are visited.
func Visit(pkgs []*Package, pre func(*Package) bool, post func(*Package)) { … }

// PrintErrors prints to os.Stderr the accumulated errors of all
// packages in the import graph rooted at pkgs, dependencies first.
// PrintErrors returns the number of errors printed.
func PrintErrors(pkgs []*Package) int { … }