1 files changed, 154 insertions, 0 deletions
diff --git a/src/cmd/go/testdata/addmod.go b/src/cmd/go/testdata/addmod.go
new file mode 100644
index 0000000..09fc8e7
--- /dev/null
+++ b/src/cmd/go/testdata/addmod.go
@@ -0,0 +1,154 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore
+
+// Addmod adds a module as a txtar archive to the testdata/mod directory.
+//
+// Usage:
+//
+//	go run addmod.go path@version...
+//
+// It should only be used for very small modules - we do not want to check
+// very large files into testdata/mod.
+//
+// It is acceptable to edit the archive afterward to remove or shorten files.
+// See mod/README for more information.
+//
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"io/fs"
+	"log"
+	"os"
+	exec "internal/execabs"
+	"path/filepath"
+	"strings"
+
+	"cmd/go/internal/txtar"
+)
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "usage: go run addmod.go path@version...\n")
+	os.Exit(2)
+}
+
+var tmpdir string
+
+func fatalf(format string, args ...interface{}) {
+	os.RemoveAll(tmpdir)
+	log.Fatalf(format, args...)
+}
+
+const goCmd = "go"
+
+func main() {
+	flag.Usage = usage
+	flag.Parse()
+	if flag.NArg() == 0 {
+		usage()
+	}
+
+	log.SetPrefix("addmod: ")
+	log.SetFlags(0)
+
+	var err error
+	tmpdir, err = os.MkdirTemp("", "addmod-")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	run := func(command string, args ...string) string {
+		cmd := exec.Command(command, args...)
+		cmd.Dir = tmpdir
+		var stderr bytes.Buffer
+		cmd.Stderr = &stderr
+		out, err := cmd.Output()
+		if err != nil {
+			fatalf("%s %s: %v\n%s", command, strings.Join(args, " "), err, stderr.Bytes())
+		}
+		return string(out)
+	}
+
+	gopath := strings.TrimSpace(run("go", "env", "GOPATH"))
+	if gopath == "" {
+		fatalf("cannot find GOPATH")
+	}
+
+	exitCode := 0
+	for _, arg := range flag.Args() {
+		if err := os.WriteFile(filepath.Join(tmpdir, "go.mod"), []byte("module m\n"), 0666); err != nil {
+			fatalf("%v", err)
+		}
+		run(goCmd, "get", "-d", arg)
+		path := arg
+		if i := strings.Index(path, "@"); i >= 0 {
+			path = path[:i]
+		}
+		out := run(goCmd, "list", "-m", "-f={{.Path}} {{.Version}} {{.Dir}}", path)
+		f := strings.Fields(out)
+		if len(f) != 3 {
+			log.Printf("go list -m %s: unexpected output %q", arg, out)
+			exitCode = 1
+			continue
+		}
+		path, vers, dir := f[0], f[1], f[2]
+		mod, err := os.ReadFile(filepath.Join(gopath, "pkg/mod/cache/download", path, "@v", vers+".mod"))
+		if err != nil {
+			log.Printf("%s: %v", arg, err)
+			exitCode = 1
+			continue
+		}
+		info, err := os.ReadFile(filepath.Join(gopath, "pkg/mod/cache/download", path, "@v", vers+".info"))
+		if err != nil {
+			log.Printf("%s: %v", arg, err)
+			exitCode = 1
+			continue
+		}
+
+		a := new(txtar.Archive)
+		title := arg
+		if !strings.Contains(arg, "@") {
+			title += "@" + vers
+		}
+		a.Comment = []byte(fmt.Sprintf("module %s\n\n", title))
+		a.Files = []txtar.File{
+			{Name: ".mod", Data: mod},
+			{Name: ".info", Data: info},
+		}
+		dir = filepath.Clean(dir)
+		err = filepath.WalkDir(dir, func(path string, info fs.DirEntry, err error) error {
+			if !info.Type().IsRegular() {
+				return nil
+			}
+			name := info.Name()
+			if name == "go.mod" || strings.HasSuffix(name, ".go") {
+				data, err := os.ReadFile(path)
+				if err != nil {
+					return err
+				}
+				a.Files = append(a.Files, txtar.File{Name: strings.TrimPrefix(path, dir+string(filepath.Separator)), Data: data})
+			}
+			return nil
+		})
+		if err != nil {
+			log.Printf("%s: %v", arg, err)
+			exitCode = 1
+			continue
+		}
+
+		data := txtar.Format(a)
+		target := filepath.Join("mod", strings.ReplaceAll(path, "/", "_")+"_"+vers+".txt")
+		if err := os.WriteFile(target, data, 0666); err != nil {
+			log.Printf("%s: %v", arg, err)
+			exitCode = 1
+			continue
+		}
+	}
+	os.RemoveAll(tmpdir)
+	os.Exit(exitCode)
+}