Print out all the files required to build a single Go package.

trimpkg.go

package main

import (
	"fmt"
	"os"

	"golang.org/x/tools/go/packages"
)

func main() {
	target := os.Args[1]

	cfg := &packages.Config{
		Mode: packages.NeedName | packages.NeedFiles | packages.NeedImports | packages.NeedDeps,
	}

	pkgs, err := packages.Load(cfg, target)
	if err != nil {
		panic(err)
	}

	seen := map[string]bool{}
	for _, p := range pkgs {
		dumpPkg(p, seen)
	}
}

func dumpPkg(p *packages.Package, seen map[string]bool) {
	if seen[p.PkgPath] {
		return
	}

	seen[p.PkgPath] = true

	fmt.Println("---------------------")
	fmt.Println("Name: " + p.Name)
	fmt.Println("Path: " + p.PkgPath)
	fmt.Println("Go files:")
	for _, f := range p.GoFiles {
		fmt.Println("\t" + f)
	}

	for _, i := range p.Imports {
		dumpPkg(i, seen)
	}
}