1// rdeps scans GOPATH for all reverse dependencies of a set of Go
2// packages.
3//
4// rdeps will not sort its output, and the order of the output is
5// undefined. Pipe its output through sort if you need stable output.
6package main
7
8import (
9	"bufio"
10	"flag"
11	"fmt"
12	"go/build"
13	"os"
14
15	"honnef.co/go/tools/version"
16
17	"github.com/kisielk/gotool"
18	"golang.org/x/tools/go/buildutil"
19	"golang.org/x/tools/refactor/importgraph"
20)
21
22func main() {
23	var tags buildutil.TagsFlag
24	flag.Var(&tags, "tags", "List of build tags")
25	stdin := flag.Bool("stdin", false, "Read packages from stdin instead of the command line")
26	recursive := flag.Bool("r", false, "Print reverse dependencies recursively")
27	printVersion := flag.Bool("version", false, "Print version and exit")
28	flag.Parse()
29
30	if *printVersion {
31		version.Print()
32		os.Exit(0)
33	}
34
35	ctx := build.Default
36	ctx.BuildTags = tags
37	var args []string
38	if *stdin {
39		s := bufio.NewScanner(os.Stdin)
40		for s.Scan() {
41			args = append(args, s.Text())
42		}
43	} else {
44		args = flag.Args()
45	}
46	if len(args) == 0 {
47		return
48	}
49	wd, err := os.Getwd()
50	if err != nil {
51		fmt.Fprintln(os.Stderr, err)
52		os.Exit(1)
53	}
54	pkgs := gotool.ImportPaths(args)
55	for i, pkg := range pkgs {
56		bpkg, err := ctx.Import(pkg, wd, build.FindOnly)
57		if err != nil {
58			continue
59		}
60		pkgs[i] = bpkg.ImportPath
61	}
62	_, reverse, errors := importgraph.Build(&ctx)
63	_ = errors
64
65	seen := map[string]bool{}
66	var printRDeps func(pkg string)
67	printRDeps = func(pkg string) {
68		for rdep := range reverse[pkg] {
69			if seen[rdep] {
70				continue
71			}
72			seen[rdep] = true
73			fmt.Println(rdep)
74			if *recursive {
75				printRDeps(rdep)
76			}
77		}
78	}
79
80	for _, pkg := range pkgs {
81		printRDeps(pkg)
82	}
83	for pkg, err := range errors {
84		fmt.Fprintf(os.Stderr, "error in package %s: %s\n", pkg, err)
85	}
86}
87