cmd/go: delete internal packages moved to x/mod

This change deletes several internal packages, replaces imports to
them with the equivalent golang.org/x/mod packages, updates x/mod, and
re-runs 'go mod vendor'.

Packages are replaced as follows:

cmd/go/internal/modfile → golang.org/x/mod/modfile
cmd/go/internal/module → golang.org/x/mod/module
cmd/go/internal/semver → golang.org/x/mod/semver
cmd/go/internal/sumdb → golang.org/x/mod/sumdb
cmd/go/internal/dirhash → golang.org/x/mod/sumdb/dirhash
cmd/go/internal/note → golang.org/x/mod/sumdb/note
cmd/go/internal/tlog → golang.org/x/mod/sumdb/tlog

Updates #31761
Fixes #34924

Change-Id: Ie3bf677bb0be49af969f654a0214243a6547eb57
Reviewed-on: https://go-review.googlesource.com/c/go/+/202698
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

src/cmd/go.mod

@@ -6,7 +6,8 @@ require (
 	github.com/google/pprof v0.0.0-20190515194954-54271f7e092f
 	github.com/ianlancetaylor/demangle v0.0.0-20180524225900-fc6590592b44 // indirect
 	golang.org/x/arch v0.0.0-20190815191158-8a70ba74b3a1
-	golang.org/x/crypto v0.0.0-20190325154230-a5d413f7728c
+	golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550
+	golang.org/x/mod v0.1.1-0.20191029194233-18c3998b6452
 	golang.org/x/sys v0.0.0-20190502175342-a43fa875dd82 // indirect
 	golang.org/x/tools v0.0.0-20191018203202-04252eccb9d5
 )

src/cmd/go.sum

@@ -5,11 +5,15 @@ github.com/ianlancetaylor/demangle v0.0.0-20180524225900-fc6590592b44/go.mod h1:
 golang.org/x/arch v0.0.0-20190815191158-8a70ba74b3a1 h1:A71BZbKSu+DtCNry/x5JKn20C+64DirDHmePEA8k0FY=
 golang.org/x/arch v0.0.0-20190815191158-8a70ba74b3a1/go.mod h1:flIaEI6LNU6xOCD5PaJvn9wGP0agmIOqjrtsKGRguv4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/crypto v0.0.0-20190325154230-a5d413f7728c h1:Vj5n4GlwjmQteupaxJ9+0FNOmBrHfq7vN4btdGoDZgI=
-golang.org/x/crypto v0.0.0-20190325154230-a5d413f7728c/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550 h1:ObdrDkeb4kJdCP557AjRjq69pTHfNouLtWZG7j9rPN8=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/mod v0.1.1-0.20191029194233-18c3998b6452 h1:ES2W0A+AqNBCkgWga22gheu9IUDjq3TDmeCdY1A7jhk=
+golang.org/x/mod v0.1.1-0.20191029194233-18c3998b6452/go.mod h1:QqPTAvyqsEbceGzBzNggFXnrqF1CaUcvgkdR5Ot7KZg=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190502175342-a43fa875dd82 h1:vsphBvatvfbhlb4PO1BYSr9dzugGxJ/SQHoNufZJq1w=
 golang.org/x/sys v0.0.0-20190502175342-a43fa875dd82/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
@@ -17,4 +21,6 @@ golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/tools v0.0.0-20191018203202-04252eccb9d5 h1:TFUhCYbgGMOGnRxJv+j0iAcxCjk8oGjXXWNejQBhUUs=
 golang.org/x/tools v0.0.0-20191018203202-04252eccb9d5/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898 h1:/atklqdjdhuosWIl6AIbOeHJjicWYPqR9bpxqxYG2pA=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 rsc.io/pdf v0.1.1/go.mod h1:n8OzWcQ6Sp37PL01nO98y4iUCRdTGarVfzxY20ICaU4=

src/cmd/go/internal/dirhash/hash_test.go

-// 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.
-
-package dirhash
-
-import (
-	"archive/zip"
-	"crypto/sha256"
-	"encoding/base64"
-	"fmt"
-	"io"
-	"io/ioutil"
-	"os"
-	"path/filepath"
-	"strings"
-	"testing"
-)
-
-func h(s string) string {
-	return fmt.Sprintf("%x", sha256.Sum256([]byte(s)))
-}
-
-func htop(k string, s string) string {
-	sum := sha256.Sum256([]byte(s))
-	return k + ":" + base64.StdEncoding.EncodeToString(sum[:])
-}
-
-func TestHash1(t *testing.T) {
-	files := []string{"xyz", "abc"}
-	open := func(name string) (io.ReadCloser, error) {
-		return ioutil.NopCloser(strings.NewReader("data for " + name)), nil
-	}
-	want := htop("h1", fmt.Sprintf("%s  %s\n%s  %s\n", h("data for abc"), "abc", h("data for xyz"), "xyz"))
-	out, err := Hash1(files, open)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if out != want {
-		t.Errorf("Hash1(...) = %s, want %s", out, want)
-	}
-
-	_, err = Hash1([]string{"xyz", "a\nbc"}, open)
-	if err == nil {
-		t.Error("Hash1: expected error on newline in filenames")
-	}
-}
-
-func TestHashDir(t *testing.T) {
-	dir, err := ioutil.TempDir("", "dirhash-test-")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.RemoveAll(dir)
-	if err := ioutil.WriteFile(filepath.Join(dir, "xyz"), []byte("data for xyz"), 0666); err != nil {
-		t.Fatal(err)
-	}
-	if err := ioutil.WriteFile(filepath.Join(dir, "abc"), []byte("data for abc"), 0666); err != nil {
-		t.Fatal(err)
-	}
-	want := htop("h1", fmt.Sprintf("%s  %s\n%s  %s\n", h("data for abc"), "prefix/abc", h("data for xyz"), "prefix/xyz"))
-	out, err := HashDir(dir, "prefix", Hash1)
-	if err != nil {
-		t.Fatalf("HashDir: %v", err)
-	}
-	if out != want {
-		t.Errorf("HashDir(...) = %s, want %s", out, want)
-	}
-}
-
-func TestHashZip(t *testing.T) {
-	f, err := ioutil.TempFile("", "dirhash-test-")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.Remove(f.Name())
-	defer f.Close()
-
-	z := zip.NewWriter(f)
-	w, err := z.Create("prefix/xyz")
-	if err != nil {
-		t.Fatal(err)
-	}
-	w.Write([]byte("data for xyz"))
-	w, err = z.Create("prefix/abc")
-	if err != nil {
-		t.Fatal(err)
-	}
-	w.Write([]byte("data for abc"))
-	if err := z.Close(); err != nil {
-		t.Fatal(err)
-	}
-	if err := f.Close(); err != nil {
-		t.Fatal(err)
-	}
-
-	want := htop("h1", fmt.Sprintf("%s  %s\n%s  %s\n", h("data for abc"), "prefix/abc", h("data for xyz"), "prefix/xyz"))
-	out, err := HashZip(f.Name(), Hash1)
-	if err != nil {
-		t.Fatalf("HashDir: %v", err)
-	}
-	if out != want {
-		t.Errorf("HashDir(...) = %s, want %s", out, want)
-	}
-}
-
-func TestDirFiles(t *testing.T) {
-	dir, err := ioutil.TempDir("", "dirfiles-test-")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.RemoveAll(dir)
-	if err := ioutil.WriteFile(filepath.Join(dir, "xyz"), []byte("data for xyz"), 0666); err != nil {
-		t.Fatal(err)
-	}
-	if err := ioutil.WriteFile(filepath.Join(dir, "abc"), []byte("data for abc"), 0666); err != nil {
-		t.Fatal(err)
-	}
-	if err := os.Mkdir(filepath.Join(dir, "subdir"), 0777); err != nil {
-		t.Fatal(err)
-	}
-	if err := ioutil.WriteFile(filepath.Join(dir, "subdir", "xyz"), []byte("data for subdir xyz"), 0666); err != nil {
-		t.Fatal(err)
-	}
-	prefix := "foo/bar@v2.3.4"
-	out, err := DirFiles(dir, prefix)
-	if err != nil {
-		t.Fatalf("DirFiles: %v", err)
-	}
-	for _, file := range out {
-		if !strings.HasPrefix(file, prefix) {
-			t.Errorf("Dir file = %s, want prefix %s", file, prefix)
-		}
-	}
-}

src/cmd/go/internal/get/path.go

@@ -11,7 +11,7 @@ import (
 	"unicode/utf8"
 )
 
-// The following functions are copied verbatim from cmd/go/internal/module/module.go,
+// The following functions are copied verbatim from golang.org/x/mod/module/module.go,
 // with a change to additionally reject Windows short-names,
 // and one to accept arbitrary letters (golang.org/issue/29101).
 //

src/cmd/go/internal/modcmd/download.go

@@ -5,16 +5,17 @@
 package modcmd
 
 import (
-	"cmd/go/internal/cfg"
 	"encoding/json"
 	"os"
 
 	"cmd/go/internal/base"
+	"cmd/go/internal/cfg"
 	"cmd/go/internal/modfetch"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/module"
 	"cmd/go/internal/par"
 	"cmd/go/internal/work"
+
+	"golang.org/x/mod/module"
 )
 
 var cmdDownload = &base.Command{

src/cmd/go/internal/modcmd/edit.go

@@ -16,10 +16,11 @@ import (
 
 	"cmd/go/internal/base"
 	"cmd/go/internal/modfetch"
-	"cmd/go/internal/modfile"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/module"
 	"cmd/go/internal/work"
+
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
 )
 
 var cmdEdit = &base.Command{

src/cmd/go/internal/modcmd/graph.go

@@ -8,15 +8,16 @@ package modcmd
 
 import (
 	"bufio"
-	"cmd/go/internal/cfg"
 	"os"
 	"sort"
 
 	"cmd/go/internal/base"
+	"cmd/go/internal/cfg"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/module"
 	"cmd/go/internal/par"
 	"cmd/go/internal/work"
+
+	"golang.org/x/mod/module"
 )
 
 var cmdGraph = &base.Command{

src/cmd/go/internal/modcmd/tidy.go

@@ -14,8 +14,9 @@ import (
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/modfetch"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/module"
 	"cmd/go/internal/work"
+
+	"golang.org/x/mod/module"
 )
 
 var cmdTidy = &base.Command{

src/cmd/go/internal/modcmd/vendor.go

@@ -18,9 +18,10 @@ import (
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/imports"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/module"
-	"cmd/go/internal/semver"
 	"cmd/go/internal/work"
+
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
 )
 
 var cmdVendor = &base.Command{

src/cmd/go/internal/modcmd/verify.go

@@ -6,17 +6,18 @@ package modcmd
 
 import (
 	"bytes"
-	"cmd/go/internal/cfg"
 	"fmt"
 	"io/ioutil"
 	"os"
 
 	"cmd/go/internal/base"
-	"cmd/go/internal/dirhash"
+	"cmd/go/internal/cfg"
 	"cmd/go/internal/modfetch"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/module"
 	"cmd/go/internal/work"
+
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/sumdb/dirhash"
 )
 
 var cmdVerify = &base.Command{

src/cmd/go/internal/modcmd/why.go

@@ -5,12 +5,14 @@
 package modcmd
 
 import (
+	"fmt"
+	"strings"
+
 	"cmd/go/internal/base"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/module"
 	"cmd/go/internal/work"
-	"fmt"
-	"strings"
+
+	"golang.org/x/mod/module"
 )
 
 var cmdWhy = &base.Command{

src/cmd/go/internal/modconv/convert.go

@@ -13,10 +13,11 @@ import (
 
 	"cmd/go/internal/base"
 	"cmd/go/internal/modfetch"
-	"cmd/go/internal/modfile"
-	"cmd/go/internal/module"
 	"cmd/go/internal/par"
-	"cmd/go/internal/semver"
+
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
 )
 
 // ConvertLegacyConfig converts legacy config to modfile.

src/cmd/go/internal/modconv/convert_test.go

@@ -19,8 +19,9 @@ import (
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/modfetch"
 	"cmd/go/internal/modfetch/codehost"
-	"cmd/go/internal/modfile"
-	"cmd/go/internal/module"
+
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
 )
 
 func TestMain(m *testing.M) {

src/cmd/go/internal/modconv/dep.go

@@ -12,9 +12,9 @@ import (
 	"strconv"
 	"strings"
 
-	"cmd/go/internal/modfile"
-	"cmd/go/internal/module"
-	"cmd/go/internal/semver"
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
 )
 
 func ParseGopkgLock(file string, data []byte) (*modfile.File, error) {

src/cmd/go/internal/modconv/glide.go

@@ -7,8 +7,8 @@ package modconv
 import (
 	"strings"
 
-	"cmd/go/internal/modfile"
-	"cmd/go/internal/module"
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
 )
 
 func ParseGlideLock(file string, data []byte) (*modfile.File, error) {

src/cmd/go/internal/modconv/glock.go

@@ -7,8 +7,8 @@ package modconv
 import (
 	"strings"
 
-	"cmd/go/internal/modfile"
-	"cmd/go/internal/module"
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
 )
 
 func ParseGLOCKFILE(file string, data []byte) (*modfile.File, error) {

src/cmd/go/internal/modconv/godeps.go

@@ -7,8 +7,8 @@ package modconv
 import (
 	"encoding/json"
 
-	"cmd/go/internal/modfile"
-	"cmd/go/internal/module"
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
 )
 
 func ParseGodepsJSON(file string, data []byte) (*modfile.File, error) {

src/cmd/go/internal/modconv/modconv.go

@@ -4,7 +4,7 @@
 
 package modconv
 
-import "cmd/go/internal/modfile"
+import "golang.org/x/mod/modfile"
 
 var Converters = map[string]func(string, []byte) (*modfile.File, error){
 	"GLOCKFILE":          ParseGLOCKFILE,

src/cmd/go/internal/modconv/tsv.go

@@ -7,8 +7,8 @@ package modconv
 import (
 	"strings"
 
-	"cmd/go/internal/modfile"
-	"cmd/go/internal/module"
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
 )
 
 func ParseDependenciesTSV(file string, data []byte) (*modfile.File, error) {

src/cmd/go/internal/modconv/vconf.go

@@ -7,8 +7,8 @@ package modconv
 import (
 	"strings"
 
-	"cmd/go/internal/modfile"
-	"cmd/go/internal/module"
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
 )
 
 func ParseVendorConf(file string, data []byte) (*modfile.File, error) {

src/cmd/go/internal/modconv/vjson.go

@@ -7,8 +7,8 @@ package modconv
 import (
 	"encoding/json"
 
-	"cmd/go/internal/modfile"
-	"cmd/go/internal/module"
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
 )
 
 func ParseVendorJSON(file string, data []byte) (*modfile.File, error) {

src/cmd/go/internal/modconv/vmanifest.go

@@ -7,8 +7,8 @@ package modconv
 import (
 	"encoding/json"
 
-	"cmd/go/internal/modfile"
-	"cmd/go/internal/module"
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
 )
 
 func ParseVendorManifest(file string, data []byte) (*modfile.File, error) {

src/cmd/go/internal/modconv/vyml.go

@@ -7,8 +7,8 @@ package modconv
 import (
 	"strings"
 
-	"cmd/go/internal/modfile"
-	"cmd/go/internal/module"
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
 )
 
 func ParseVendorYML(file string, data []byte) (*modfile.File, error) {

src/cmd/go/internal/modfetch/bootstrap.go

@@ -6,7 +6,7 @@
 
 package modfetch
 
-import "cmd/go/internal/module"
+import "golang.org/x/mod/module"
 
 func useSumDB(mod module.Version) bool {
 	return false

src/cmd/go/internal/modfetch/cache.go

@@ -18,10 +18,11 @@ import (
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/lockedfile"
 	"cmd/go/internal/modfetch/codehost"
-	"cmd/go/internal/module"
 	"cmd/go/internal/par"
 	"cmd/go/internal/renameio"
-	"cmd/go/internal/semver"
+
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
 )
 
 var QuietLookup bool // do not print about lookups

src/cmd/go/internal/modfetch/codehost/git.go

@@ -22,8 +22,9 @@ import (
 
 	"cmd/go/internal/lockedfile"
 	"cmd/go/internal/par"
-	"cmd/go/internal/semver"
 	"cmd/go/internal/web"
+
+	"golang.org/x/mod/semver"
 )
 
 // GitRepo returns the code repository at the given Git remote reference.

src/cmd/go/internal/modfetch/coderepo.go

@@ -16,9 +16,10 @@ import (
 	"time"
 
 	"cmd/go/internal/modfetch/codehost"
-	"cmd/go/internal/modfile"
-	"cmd/go/internal/module"
-	"cmd/go/internal/semver"
+
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
 )
 
 // A codeRepo implements modfetch.Repo using an underlying codehost.Repo.

src/cmd/go/internal/modfetch/fetch.go

@@ -19,10 +19,11 @@ import (
 
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
-	"cmd/go/internal/dirhash"
-	"cmd/go/internal/module"
 	"cmd/go/internal/par"
 	"cmd/go/internal/renameio"
+
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/sumdb/dirhash"
 )
 
 var downloadCache par.Cache

src/cmd/go/internal/modfetch/proxy.go

@@ -22,9 +22,10 @@ import (
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/modfetch/codehost"
-	"cmd/go/internal/module"
-	"cmd/go/internal/semver"
 	"cmd/go/internal/web"
+
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
 )
 
 var HelpGoproxy = &base.Command{

src/cmd/go/internal/modfetch/pseudo.go

@@ -40,9 +40,10 @@ import (
 	"strings"
 	"time"
 
-	"cmd/go/internal/module"
-	"cmd/go/internal/semver"
 	"internal/lazyregexp"
+
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
 )
 
 var pseudoVersionRE = lazyregexp.New(`^v[0-9]+\.(0\.0-|\d+\.\d+-([^+]*\.)?0\.)\d{14}-[A-Za-z0-9]+(\+[0-9A-Za-z-]+(\.[0-9A-Za-z-]+)*)?$`)

src/cmd/go/internal/modfetch/repo.go

@@ -17,9 +17,10 @@ import (
 	"cmd/go/internal/get"
 	"cmd/go/internal/modfetch/codehost"
 	"cmd/go/internal/par"
-	"cmd/go/internal/semver"
 	"cmd/go/internal/str"
 	web "cmd/go/internal/web"
+
+	"golang.org/x/mod/semver"
 )
 
 const traceRepo = false // trace all repo actions, for debugging

src/cmd/go/internal/modfetch/sumdb.go

@@ -24,11 +24,11 @@ import (
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/get"
 	"cmd/go/internal/lockedfile"
-	"cmd/go/internal/module"
-	"cmd/go/internal/note"
 	"cmd/go/internal/str"
-	"cmd/go/internal/sumdb"
 	"cmd/go/internal/web"
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/sumdb"
+	"golang.org/x/mod/sumdb/note"
 )
 
 // useSumDB reports whether to use the Go checksum database for the given module.

src/cmd/go/internal/modfetch/unzip.go

@@ -15,8 +15,8 @@ import (
 	"strings"
 
 	"cmd/go/internal/modfetch/codehost"
-	"cmd/go/internal/module"
 	"cmd/go/internal/str"
+	"golang.org/x/mod/module"
 )
 
 func Unzip(dir, zipfile, prefix string, maxSize int64) error {

src/cmd/go/internal/modfile/rule_test.go

-// 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.
-
-package modfile
-
-import (
-	"bytes"
-	"fmt"
-	"testing"
-
-	"cmd/go/internal/module"
-)
-
-var addRequireTests = []struct {
-	in   string
-	path string
-	vers string
-	out  string
-}{
-	{
-		`
-		module m
-		require x.y/z v1.2.3
-		`,
-		"x.y/z", "v1.5.6",
-		`
-		module m
-		require x.y/z v1.5.6
-		`,
-	},
-	{
-		`
-		module m
-		require x.y/z v1.2.3
-		`,
-		"x.y/w", "v1.5.6",
-		`
-		module m
-		require (
-			x.y/z v1.2.3
-			x.y/w v1.5.6
-		)
-		`,
-	},
-	{
-		`
-		module m
-		require x.y/z v1.2.3
-		require x.y/q/v2 v2.3.4
-		`,
-		"x.y/w", "v1.5.6",
-		`
-		module m
-		require x.y/z v1.2.3
-		require (
-			x.y/q/v2 v2.3.4
-			x.y/w v1.5.6
-		)
-		`,
-	},
-}
-
-var setRequireTests = []struct {
-	in   string
-	mods []struct {
-		path string
-		vers string
-	}
-	out string
-}{
-	{
-		`module m
-		require (
-			x.y/b v1.2.3
-
-			x.y/a v1.2.3
-		)
-		`,
-		[]struct {
-			path string
-			vers string
-		}{
-			{"x.y/a", "v1.2.3"},
-			{"x.y/b", "v1.2.3"},
-			{"x.y/c", "v1.2.3"},
-		},
-		`module m
-		require (
-			x.y/a v1.2.3
-			x.y/b v1.2.3
-			x.y/c v1.2.3
-		)
-		`,
-	},
-}
-
-func TestAddRequire(t *testing.T) {
-	for i, tt := range addRequireTests {
-		t.Run(fmt.Sprintf("#%d", i), func(t *testing.T) {
-			f, err := Parse("in", []byte(tt.in), nil)
-			if err != nil {
-				t.Fatal(err)
-			}
-			g, err := Parse("out", []byte(tt.out), nil)
-			if err != nil {
-				t.Fatal(err)
-			}
-			golden, err := g.Format()
-			if err != nil {
-				t.Fatal(err)
-			}
-
-			if err := f.AddRequire(tt.path, tt.vers); err != nil {
-				t.Fatal(err)
-			}
-			out, err := f.Format()
-			if err != nil {
-				t.Fatal(err)
-			}
-			if !bytes.Equal(out, golden) {
-				t.Errorf("have:\n%s\nwant:\n%s", out, golden)
-			}
-		})
-	}
-}
-
-func TestSetRequire(t *testing.T) {
-	for i, tt := range setRequireTests {
-		t.Run(fmt.Sprintf("#%d", i), func(t *testing.T) {
-			f, err := Parse("in", []byte(tt.in), nil)
-			if err != nil {
-				t.Fatal(err)
-			}
-			g, err := Parse("out", []byte(tt.out), nil)
-			if err != nil {
-				t.Fatal(err)
-			}
-			golden, err := g.Format()
-			if err != nil {
-				t.Fatal(err)
-			}
-			var mods []*Require
-			for _, mod := range tt.mods {
-				mods = append(mods, &Require{
-					Mod: module.Version{
-						Path:    mod.path,
-						Version: mod.vers,
-					},
-				})
-			}
-
-			f.SetRequire(mods)
-			out, err := f.Format()
-			if err != nil {
-				t.Fatal(err)
-			}
-			if !bytes.Equal(out, golden) {
-				t.Errorf("have:\n%s\nwant:\n%s", out, golden)
-			}
-		})
-	}
-}

src/cmd/go/internal/modfile/testdata/block.golden

-// comment
-x "y" z
-
-// block
-block ( // block-eol
-	// x-before-line
-
-	"x" ( y // x-eol
-	"x1"
-	"x2"
-	// line
-	"x3"
-	"x4"
-
-	"x5"
-
-	// y-line
-	"y" //  y-eol
-
-	"z" // z-eol
-) // block-eol2
-
-block2 (
-	x
-	y
-	z
-)
-
-// eof

src/cmd/go/internal/modfile/testdata/block.in

-// comment
-x "y" z
-
-// block
-block ( // block-eol
-	// x-before-line
-	
-	"x" ( y // x-eol
-	"x1"
-	"x2"
-	// line
-	"x3"
-	"x4"
-	
-	"x5"
-	
-	// y-line
-	"y" //  y-eol
-	
-	"z" // z-eol
-) // block-eol2
-
-
-block2 (x
-	y
-	z
-)
-
-// eof

src/cmd/go/internal/modfile/testdata/comment.golden

-// comment
-module "x" // eol
-
-// mid comment
-
-// comment 2
-// comment 2 line 2
-module "y" // eoy
-
-// comment 3

src/cmd/go/internal/modfile/testdata/comment.in

-// comment
-module "x" // eol
-// mid comment
-
-// comment 2
-// comment 2 line 2
-module "y" // eoy
-// comment 3

src/cmd/go/internal/modfile/testdata/gopkg.in.golden

-module x
-
-require (
-	gopkg.in/mgo.v2 v2.0.0-20160818020120-3f83fa500528
-	gopkg.in/yaml.v2 v2.2.1
-)

src/cmd/go/internal/modfile/testdata/module.golden

-module abc

src/cmd/go/internal/modfile/testdata/module.in

-module "abc"

src/cmd/go/internal/modfile/testdata/replace.golden

-module abc
-
-replace xyz v1.2.3 => /tmp/z
-
-replace xyz v1.3.4 => my/xyz v1.3.4-me

src/cmd/go/internal/modfile/testdata/replace.in

-module "abc"
-
-replace "xyz" v1.2.3 => "/tmp/z"
-
-replace "xyz" v1.3.4 => "my/xyz" v1.3.4-me

src/cmd/go/internal/modfile/testdata/replace2.golden

-module abc
-
-replace (
-	xyz v1.2.3 => /tmp/z
-	xyz v1.3.4 => my/xyz v1.3.4-me
-	xyz v1.4.5 => "/tmp/my dir"
-	xyz v1.5.6 => my/xyz v1.5.6
-
-	xyz => my/other/xyz v1.5.4
-)

src/cmd/go/internal/modfile/testdata/replace2.in

-module "abc"
-
-replace (
-	"xyz" v1.2.3 => "/tmp/z"
-	"xyz" v1.3.4 => "my/xyz" "v1.3.4-me"
-	xyz "v1.4.5" => "/tmp/my dir"
-	xyz v1.5.6 => my/xyz v1.5.6
-
-	xyz => my/other/xyz v1.5.4
-)

src/cmd/go/internal/modfile/testdata/rule1.golden

-module "x"
-
-module "y"
-
-require "x"
-
-require x

src/cmd/go/internal/modget/get.go

@@ -6,24 +6,26 @@
 package modget
 
 import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"sync"
+
 	"cmd/go/internal/base"
 	"cmd/go/internal/get"
 	"cmd/go/internal/imports"
 	"cmd/go/internal/load"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/module"
 	"cmd/go/internal/mvs"
 	"cmd/go/internal/par"
 	"cmd/go/internal/search"
-	"cmd/go/internal/semver"
 	"cmd/go/internal/work"
-	"errors"
-	"fmt"
-	"os"
-	"path/filepath"
-	"sort"
-	"strings"
-	"sync"
+
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
 )
 
 var CmdGet = &base.Command{

src/cmd/go/internal/modload/build.go

@@ -6,13 +6,6 @@ package modload
 
 import (
 	"bytes"
-	"cmd/go/internal/base"
-	"cmd/go/internal/cfg"
-	"cmd/go/internal/modfetch"
-	"cmd/go/internal/modinfo"
-	"cmd/go/internal/module"
-	"cmd/go/internal/search"
-	"cmd/go/internal/semver"
 	"encoding/hex"
 	"fmt"
 	"internal/goroot"
@@ -20,6 +13,15 @@ import (
 	"path/filepath"
 	"runtime/debug"
 	"strings"
+
+	"cmd/go/internal/base"
+	"cmd/go/internal/cfg"
+	"cmd/go/internal/modfetch"
+	"cmd/go/internal/modinfo"
+	"cmd/go/internal/search"
+
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
 )
 
 var (

src/cmd/go/internal/modload/import.go

@@ -18,11 +18,12 @@ import (
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/load"
 	"cmd/go/internal/modfetch"
-	"cmd/go/internal/module"
 	"cmd/go/internal/par"
 	"cmd/go/internal/search"
-	"cmd/go/internal/semver"
 	"cmd/go/internal/str"
+
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
 )
 
 type ImportMissingError struct {

src/cmd/go/internal/modload/init.go

@@ -25,12 +25,13 @@ import (
 	"cmd/go/internal/modconv"
 	"cmd/go/internal/modfetch"
 	"cmd/go/internal/modfetch/codehost"
-	"cmd/go/internal/modfile"
-	"cmd/go/internal/module"
 	"cmd/go/internal/mvs"
 	"cmd/go/internal/renameio"
 	"cmd/go/internal/search"
-	"cmd/go/internal/semver"
+
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
 )
 
 var (

src/cmd/go/internal/modload/list.go

@@ -13,9 +13,10 @@ import (
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/modinfo"
-	"cmd/go/internal/module"
 	"cmd/go/internal/par"
 	"cmd/go/internal/search"
+
+	"golang.org/x/mod/module"
 )
 
 func ListModules(args []string, listU, listVersions bool) []*modinfo.ModulePublic {

src/cmd/go/internal/modload/load.go

@@ -22,13 +22,14 @@ import (
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/imports"
 	"cmd/go/internal/modfetch"
-	"cmd/go/internal/modfile"
-	"cmd/go/internal/module"
 	"cmd/go/internal/mvs"
 	"cmd/go/internal/par"
 	"cmd/go/internal/search"
-	"cmd/go/internal/semver"
 	"cmd/go/internal/str"
+
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
 )
 
 // buildList is the list of modules to use for building packages.

src/cmd/go/internal/modload/query.go

@@ -14,10 +14,11 @@ import (
 
 	"cmd/go/internal/imports"
 	"cmd/go/internal/modfetch"
-	"cmd/go/internal/module"
 	"cmd/go/internal/search"
-	"cmd/go/internal/semver"
 	"cmd/go/internal/str"
+
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
 )
 
 // Query looks up a revision of a given module given a version query string.

src/cmd/go/internal/modload/query_test.go

@@ -17,7 +17,8 @@ import (
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/modfetch"
 	"cmd/go/internal/modfetch/codehost"
-	"cmd/go/internal/module"
+
+	"golang.org/x/mod/module"
 )
 
 func TestMain(m *testing.M) {

src/cmd/go/internal/modload/search.go

@@ -13,8 +13,9 @@ import (
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/imports"
-	"cmd/go/internal/module"
 	"cmd/go/internal/search"
+
+	"golang.org/x/mod/module"
 )
 
 // matchPackages returns a list of packages in the list of modules

src/cmd/go/internal/mvs/mvs.go

@@ -13,8 +13,9 @@ import (
 	"sync"
 	"sync/atomic"
 
-	"cmd/go/internal/module"
 	"cmd/go/internal/par"
+
+	"golang.org/x/mod/module"
 )
 
 // A Reqs is the requirement graph on which Minimal Version Selection (MVS) operates.

src/cmd/go/internal/mvs/mvs_test.go

@@ -10,7 +10,7 @@ import (
 	"strings"
 	"testing"
 
-	"cmd/go/internal/module"
+	"golang.org/x/mod/module"
 )
 
 var tests = `

src/cmd/go/internal/note/example_test.go

-// Copyright 2019 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.
-
-package note_test
-
-import (
-	"fmt"
-	"io"
-	"os"
-
-	"cmd/go/internal/note"
-)
-
-func ExampleSign() {
-	skey := "PRIVATE+KEY+PeterNeumann+c74f20a3+AYEKFALVFGyNhPJEMzD1QIDr+Y7hfZx09iUvxdXHKDFz"
-	text := "If you think cryptography is the answer to your problem,\n" +
-		"then you don't know what your problem is.\n"
-
-	signer, err := note.NewSigner(skey)
-	if err != nil {
-		fmt.Println(err)
-		return
-	}
-
-	msg, err := note.Sign(&note.Note{Text: text}, signer)
-	if err != nil {
-		fmt.Println(err)
-		return
-	}
-	os.Stdout.Write(msg)
-
-	// Output:
-	// If you think cryptography is the answer to your problem,
-	// then you don't know what your problem is.
-	//
-	// — PeterNeumann x08go/ZJkuBS9UG/SffcvIAQxVBtiFupLLr8pAcElZInNIuGUgYN1FFYC2pZSNXgKvqfqdngotpRZb6KE6RyyBwJnAM=
-}
-
-func ExampleOpen() {
-	vkey := "PeterNeumann+c74f20a3+ARpc2QcUPDhMQegwxbzhKqiBfsVkmqq/LDE4izWy10TW"
-	msg := []byte("If you think cryptography is the answer to your problem,\n" +
-		"then you don't know what your problem is.\n" +
-		"\n" +
-		"— PeterNeumann x08go/ZJkuBS9UG/SffcvIAQxVBtiFupLLr8pAcElZInNIuGUgYN1FFYC2pZSNXgKvqfqdngotpRZb6KE6RyyBwJnAM=\n")
-
-	verifier, err := note.NewVerifier(vkey)
-	if err != nil {
-		fmt.Println(err)
-		return
-	}
-	verifiers := note.VerifierList(verifier)
-
-	n, err := note.Open(msg, verifiers)
-	if err != nil {
-		fmt.Println(err)
-		return
-	}
-	fmt.Printf("%s (%08x):\n%s", n.Sigs[0].Name, n.Sigs[0].Hash, n.Text)
-
-	// Output:
-	// PeterNeumann (c74f20a3):
-	// If you think cryptography is the answer to your problem,
-	// then you don't know what your problem is.
-}
-
-var rand = struct {
-	Reader io.Reader
-}{
-	zeroReader{},
-}
-
-type zeroReader struct{}
-
-func (zeroReader) Read(buf []byte) (int, error) {
-	for i := range buf {
-		buf[i] = 0
-	}
-	return len(buf), nil
-}
-
-func ExampleSign_add_signatures() {
-	vkey := "PeterNeumann+c74f20a3+ARpc2QcUPDhMQegwxbzhKqiBfsVkmqq/LDE4izWy10TW"
-	msg := []byte("If you think cryptography is the answer to your problem,\n" +
-		"then you don't know what your problem is.\n" +
-		"\n" +
-		"— PeterNeumann x08go/ZJkuBS9UG/SffcvIAQxVBtiFupLLr8pAcElZInNIuGUgYN1FFYC2pZSNXgKvqfqdngotpRZb6KE6RyyBwJnAM=\n")
-
-	verifier, err := note.NewVerifier(vkey)
-	if err != nil {
-		fmt.Println(err)
-		return
-	}
-	verifiers := note.VerifierList(verifier)
-
-	n, err := note.Open([]byte(msg), verifiers)
-	if err != nil {
-		fmt.Println(err)
-		return
-	}
-
-	skey, vkey, err := note.GenerateKey(rand.Reader, "EnochRoot")
-	if err != nil {
-		fmt.Println(err)
-		return
-	}
-	_ = vkey // give to verifiers
-
-	me, err := note.NewSigner(skey)
-	if err != nil {
-		fmt.Println(err)
-		return
-	}
-
-	msg, err = note.Sign(n, me)
-	if err != nil {
-		fmt.Println(err)
-		return
-	}
-	os.Stdout.Write(msg)
-
-	// Output:
-	// If you think cryptography is the answer to your problem,
-	// then you don't know what your problem is.
-	//
-	// — PeterNeumann x08go/ZJkuBS9UG/SffcvIAQxVBtiFupLLr8pAcElZInNIuGUgYN1FFYC2pZSNXgKvqfqdngotpRZb6KE6RyyBwJnAM=
-	// — EnochRoot rwz+eBzmZa0SO3NbfRGzPCpDckykFXSdeX+MNtCOXm2/5n2tiOHp+vAF1aGrQ5ovTG01oOTGwnWLox33WWd1RvMc+QQ=
-}

src/cmd/go/internal/semver/semver_test.go

-// 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.
-
-package semver
-
-import (
-	"strings"
-	"testing"
-)
-
-var tests = []struct {
-	in  string
-	out string
-}{
-	{"bad", ""},
-	{"v1-alpha.beta.gamma", ""},
-	{"v1-pre", ""},
-	{"v1+meta", ""},
-	{"v1-pre+meta", ""},
-	{"v1.2-pre", ""},
-	{"v1.2+meta", ""},
-	{"v1.2-pre+meta", ""},
-	{"v1.0.0-alpha", "v1.0.0-alpha"},
-	{"v1.0.0-alpha.1", "v1.0.0-alpha.1"},
-	{"v1.0.0-alpha.beta", "v1.0.0-alpha.beta"},
-	{"v1.0.0-beta", "v1.0.0-beta"},
-	{"v1.0.0-beta.2", "v1.0.0-beta.2"},
-	{"v1.0.0-beta.11", "v1.0.0-beta.11"},
-	{"v1.0.0-rc.1", "v1.0.0-rc.1"},
-	{"v1", "v1.0.0"},
-	{"v1.0", "v1.0.0"},
-	{"v1.0.0", "v1.0.0"},
-	{"v1.2", "v1.2.0"},
-	{"v1.2.0", "v1.2.0"},
-	{"v1.2.3-456", "v1.2.3-456"},
-	{"v1.2.3-456.789", "v1.2.3-456.789"},
-	{"v1.2.3-456-789", "v1.2.3-456-789"},
-	{"v1.2.3-456a", "v1.2.3-456a"},
-	{"v1.2.3-pre", "v1.2.3-pre"},
-	{"v1.2.3-pre+meta", "v1.2.3-pre"},
-	{"v1.2.3-pre.1", "v1.2.3-pre.1"},
-	{"v1.2.3-zzz", "v1.2.3-zzz"},
-	{"v1.2.3", "v1.2.3"},
-	{"v1.2.3+meta", "v1.2.3"},
-	{"v1.2.3+meta-pre", "v1.2.3"},
-	{"v1.2.3+meta-pre.sha.256a", "v1.2.3"},
-}
-
-func TestIsValid(t *testing.T) {
-	for _, tt := range tests {
-		ok := IsValid(tt.in)
-		if ok != (tt.out != "") {
-			t.Errorf("IsValid(%q) = %v, want %v", tt.in, ok, !ok)
-		}
-	}
-}
-
-func TestCanonical(t *testing.T) {
-	for _, tt := range tests {
-		out := Canonical(tt.in)
-		if out != tt.out {
-			t.Errorf("Canonical(%q) = %q, want %q", tt.in, out, tt.out)
-		}
-	}
-}
-
-func TestMajor(t *testing.T) {
-	for _, tt := range tests {
-		out := Major(tt.in)
-		want := ""
-		if i := strings.Index(tt.out, "."); i >= 0 {
-			want = tt.out[:i]
-		}
-		if out != want {
-			t.Errorf("Major(%q) = %q, want %q", tt.in, out, want)
-		}
-	}
-}
-
-func TestMajorMinor(t *testing.T) {
-	for _, tt := range tests {
-		out := MajorMinor(tt.in)
-		var want string
-		if tt.out != "" {
-			want = tt.in
-			if i := strings.Index(want, "+"); i >= 0 {
-				want = want[:i]
-			}
-			if i := strings.Index(want, "-"); i >= 0 {
-				want = want[:i]
-			}
-			switch strings.Count(want, ".") {
-			case 0:
-				want += ".0"
-			case 1:
-				// ok
-			case 2:
-				want = want[:strings.LastIndex(want, ".")]
-			}
-		}
-		if out != want {
-			t.Errorf("MajorMinor(%q) = %q, want %q", tt.in, out, want)
-		}
-	}
-}
-
-func TestPrerelease(t *testing.T) {
-	for _, tt := range tests {
-		pre := Prerelease(tt.in)
-		var want string
-		if tt.out != "" {
-			if i := strings.Index(tt.out, "-"); i >= 0 {
-				want = tt.out[i:]
-			}
-		}
-		if pre != want {
-			t.Errorf("Prerelease(%q) = %q, want %q", tt.in, pre, want)
-		}
-	}
-}
-
-func TestBuild(t *testing.T) {
-	for _, tt := range tests {
-		build := Build(tt.in)
-		var want string
-		if tt.out != "" {
-			if i := strings.Index(tt.in, "+"); i >= 0 {
-				want = tt.in[i:]
-			}
-		}
-		if build != want {
-			t.Errorf("Build(%q) = %q, want %q", tt.in, build, want)
-		}
-	}
-}
-
-func TestCompare(t *testing.T) {
-	for i, ti := range tests {
-		for j, tj := range tests {
-			cmp := Compare(ti.in, tj.in)
-			var want int
-			if ti.out == tj.out {
-				want = 0
-			} else if i < j {
-				want = -1
-			} else {
-				want = +1
-			}
-			if cmp != want {
-				t.Errorf("Compare(%q, %q) = %d, want %d", ti.in, tj.in, cmp, want)
-			}
-		}
-	}
-}
-
-func TestMax(t *testing.T) {
-	for i, ti := range tests {
-		for j, tj := range tests {
-			max := Max(ti.in, tj.in)
-			want := Canonical(ti.in)
-			if i < j {
-				want = Canonical(tj.in)
-			}
-			if max != want {
-				t.Errorf("Max(%q, %q) = %q, want %q", ti.in, tj.in, max, want)
-			}
-		}
-	}
-}
-
-var (
-	v1 = "v1.0.0+metadata-dash"
-	v2 = "v1.0.0+metadata-dash1"
-)
-
-func BenchmarkCompare(b *testing.B) {
-	for i := 0; i < b.N; i++ {
-		if Compare(v1, v2) != 0 {
-			b.Fatalf("bad compare")
-		}
-	}
-}

src/cmd/go/internal/tlog/ct_test.go

-// Copyright 2019 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.
-
-package tlog
-
-import (
-	"encoding/json"
-	"fmt"
-	"io/ioutil"
-	"net/http"
-	"net/url"
-	"os"
-	"testing"
-)
-
-func TestCertificateTransparency(t *testing.T) {
-	// Test that we can verify actual Certificate Transparency proofs.
-	// (The other tests check that we can verify our own proofs;
-	// this is a test that the two are compatible.)
-
-	if testing.Short() {
-		t.Skip("skipping in -short mode")
-	}
-
-	var root ctTree
-	httpGET(t, "http://ct.googleapis.com/logs/argon2020/ct/v1/get-sth", &root)
-
-	var leaf ctEntries
-	httpGET(t, "http://ct.googleapis.com/logs/argon2020/ct/v1/get-entries?start=10000&end=10000", &leaf)
-	hash := RecordHash(leaf.Entries[0].Data)
-
-	var rp ctRecordProof
-	httpGET(t, "http://ct.googleapis.com/logs/argon2020/ct/v1/get-proof-by-hash?tree_size="+fmt.Sprint(root.Size)+"&hash="+url.QueryEscape(hash.String()), &rp)
-
-	err := CheckRecord(rp.Proof, root.Size, root.Hash, 10000, hash)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	var tp ctTreeProof
-	httpGET(t, "http://ct.googleapis.com/logs/argon2020/ct/v1/get-sth-consistency?first=3654490&second="+fmt.Sprint(root.Size), &tp)
-
-	oh, _ := ParseHash("AuIZ5V6sDUj1vn3Y1K85oOaQ7y+FJJKtyRTl1edIKBQ=")
-	err = CheckTree(tp.Proof, root.Size, root.Hash, 3654490, oh)
-	if err != nil {
-		t.Fatal(err)
-	}
-}
-
-type ctTree struct {
-	Size int64 `json:"tree_size"`
-	Hash Hash  `json:"sha256_root_hash"`
-}
-
-type ctEntries struct {
-	Entries []*ctEntry
-}
-
-type ctEntry struct {
-	Data []byte `json:"leaf_input"`
-}
-
-type ctRecordProof struct {
-	Index int64       `json:"leaf_index"`
-	Proof RecordProof `json:"audit_path"`
-}
-
-type ctTreeProof struct {
-	Proof TreeProof `json:"consistency"`
-}
-
-func httpGET(t *testing.T, url string, targ interface{}) {
-	if testing.Verbose() {
-		println()
-		println(url)
-	}
-	resp, err := http.Get(url)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer resp.Body.Close()
-	data, err := ioutil.ReadAll(resp.Body)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if testing.Verbose() {
-		os.Stdout.Write(data)
-	}
-	err = json.Unmarshal(data, targ)
-	if err != nil {
-		println(url)
-		os.Stdout.Write(data)
-		t.Fatal(err)
-	}
-}

src/cmd/go/internal/tlog/note_test.go

-// Copyright 2019 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.
-
-package tlog
-
-import (
-	"strings"
-	"testing"
-)
-
-func TestFormatTree(t *testing.T) {
-	n := int64(123456789012)
-	h := RecordHash([]byte("hello world"))
-	golden := "go.sum database tree\n123456789012\nTszzRgjTG6xce+z2AG31kAXYKBgQVtCSCE40HmuwBb0=\n"
-	b := FormatTree(Tree{n, h})
-	if string(b) != golden {
-		t.Errorf("FormatTree(...) = %q, want %q", b, golden)
-	}
-}
-
-func TestParseTree(t *testing.T) {
-	in := "go.sum database tree\n123456789012\nTszzRgjTG6xce+z2AG31kAXYKBgQVtCSCE40HmuwBb0=\n"
-	goldH := RecordHash([]byte("hello world"))
-	goldN := int64(123456789012)
-	tree, err := ParseTree([]byte(in))
-	if tree.N != goldN || tree.Hash != goldH || err != nil {
-		t.Fatalf("ParseTree(...) = Tree{%d, %v}, %v, want Tree{%d, %v}, nil", tree.N, tree.Hash, err, goldN, goldH)
-	}
-
-	// Check invalid trees.
-	var badTrees = []string{
-		"not-" + in,
-		"go.sum database tree\n0xabcdef\nTszzRgjTG6xce+z2AG31kAXYKBgQVtCSCE40HmuwBb0=\n",
-		"go.sum database tree\n123456789012\nTszzRgjTG6xce+z2AG31kAXYKBgQVtCSCE40HmuwBTOOBIG=\n",
-	}
-	for _, bad := range badTrees {
-		_, err := ParseTree([]byte(bad))
-		if err == nil {
-			t.Fatalf("ParseTree(%q) succeeded, want failure", in)
-		}
-	}
-
-	// Check junk on end is ignored.
-	var goodTrees = []string{
-		in + "JOE",
-		in + "JOE\n",
-		in + strings.Repeat("JOE\n", 1000),
-	}
-	for _, good := range goodTrees {
-		_, err := ParseTree([]byte(good))
-		if tree.N != goldN || tree.Hash != goldH || err != nil {
-			t.Fatalf("ParseTree(...+%q) = Tree{%d, %v}, %v, want Tree{%d, %v}, nil", good[len(in):], tree.N, tree.Hash, err, goldN, goldH)
-		}
-	}
-}
-
-func TestFormatRecord(t *testing.T) {
-	id := int64(123456789012)
-	text := "hello, world\n"
-	golden := "123456789012\nhello, world\n\n"
-	msg, err := FormatRecord(id, []byte(text))
-	if err != nil {
-		t.Fatalf("FormatRecord: %v", err)
-	}
-	if string(msg) != golden {
-		t.Fatalf("FormatRecord(...) = %q, want %q", msg, golden)
-	}
-
-	var badTexts = []string{
-		"",
-		"hello\nworld",
-		"hello\n\nworld\n",
-		"hello\x01world\n",
-	}
-	for _, bad := range badTexts {
-		msg, err := FormatRecord(id, []byte(bad))
-		if err == nil {
-			t.Errorf("FormatRecord(id, %q) = %q, want error", bad, msg)
-		}
-	}
-}
-
-func TestParseRecord(t *testing.T) {
-	in := "123456789012\nhello, world\n\njunk on end\x01\xff"
-	goldID := int64(123456789012)
-	goldText := "hello, world\n"
-	goldRest := "junk on end\x01\xff"
-	id, text, rest, err := ParseRecord([]byte(in))
-	if id != goldID || string(text) != goldText || string(rest) != goldRest || err != nil {
-		t.Fatalf("ParseRecord(%q) = %d, %q, %q, %v, want %d, %q, %q, nil", in, id, text, rest, err, goldID, goldText, goldRest)
-	}
-
-	in = "123456789012\nhello, world\n\n"
-	id, text, rest, err = ParseRecord([]byte(in))
-	if id != goldID || string(text) != goldText || len(rest) != 0 || err != nil {
-		t.Fatalf("ParseRecord(%q) = %d, %q, %q, %v, want %d, %q, %q, nil", in, id, text, rest, err, goldID, goldText, "")
-	}
-	if rest == nil {
-		t.Fatalf("ParseRecord(%q): rest = []byte(nil), want []byte{}", in)
-	}
-
-	// Check invalid records.
-	var badRecords = []string{
-		"not-" + in,
-		"123\nhello\x01world\n\n",
-		"123\nhello\xffworld\n\n",
-		"123\nhello world\n",
-		"0x123\nhello world\n\n",
-	}
-	for _, bad := range badRecords {
-		id, text, rest, err := ParseRecord([]byte(bad))
-		if err == nil {
-			t.Fatalf("ParseRecord(%q) = %d, %q, %q, nil, want error", in, id, text, rest)
-		}
-	}
-}

src/cmd/go/internal/tlog/tlog_test.go

-// Copyright 2019 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.
-
-package tlog
-
-import (
-	"bytes"
-	"fmt"
-	"testing"
-)
-
-type testHashStorage []Hash
-
-func (t testHashStorage) ReadHash(level int, n int64) (Hash, error) {
-	return t[StoredHashIndex(level, n)], nil
-}
-
-func (t testHashStorage) ReadHashes(index []int64) ([]Hash, error) {
-	// It's not required by HashReader that indexes be in increasing order,
-	// but check that the functions we are testing only ever ask for
-	// indexes in increasing order.
-	for i := 1; i < len(index); i++ {
-		if index[i-1] >= index[i] {
-			panic("indexes out of order")
-		}
-	}
-
-	out := make([]Hash, len(index))
-	for i, x := range index {
-		out[i] = t[x]
-	}
-	return out, nil
-}
-
-type testTilesStorage struct {
-	unsaved int
-	m       map[Tile][]byte
-}
-
-func (t testTilesStorage) Height() int {
-	return 2
-}
-
-func (t *testTilesStorage) SaveTiles(tiles []Tile, data [][]byte) {
-	t.unsaved -= len(tiles)
-}
-
-func (t *testTilesStorage) ReadTiles(tiles []Tile) ([][]byte, error) {
-	out := make([][]byte, len(tiles))
-	for i, tile := range tiles {
-		out[i] = t.m[tile]
-	}
-	t.unsaved += len(tiles)
-	return out, nil
-}
-
-func TestTree(t *testing.T) {
-	var trees []Hash
-	var leafhashes []Hash
-	var storage testHashStorage
-	tiles := make(map[Tile][]byte)
-	const testH = 2
-	for i := int64(0); i < 100; i++ {
-		data := []byte(fmt.Sprintf("leaf %d", i))
-		hashes, err := StoredHashes(i, data, storage)
-		if err != nil {
-			t.Fatal(err)
-		}
-		leafhashes = append(leafhashes, RecordHash(data))
-		oldStorage := len(storage)
-		storage = append(storage, hashes...)
-		if count := StoredHashCount(i + 1); count != int64(len(storage)) {
-			t.Errorf("StoredHashCount(%d) = %d, have %d StoredHashes", i+1, count, len(storage))
-		}
-		th, err := TreeHash(i+1, storage)
-		if err != nil {
-			t.Fatal(err)
-		}
-
-		for _, tile := range NewTiles(testH, i, i+1) {
-			data, err := ReadTileData(tile, storage)
-			if err != nil {
-				t.Fatal(err)
-			}
-			old := Tile{H: tile.H, L: tile.L, N: tile.N, W: tile.W - 1}
-			oldData := tiles[old]
-			if len(oldData) != len(data)-HashSize || !bytes.Equal(oldData, data[:len(oldData)]) {
-				t.Fatalf("tile %v not extending earlier tile %v", tile.Path(), old.Path())
-			}
-			tiles[tile] = data
-		}
-		for _, tile := range NewTiles(testH, 0, i+1) {
-			data, err := ReadTileData(tile, storage)
-			if err != nil {
-				t.Fatal(err)
-			}
-			if !bytes.Equal(tiles[tile], data) {
-				t.Fatalf("mismatch at %+v", tile)
-			}
-		}
-		for _, tile := range NewTiles(testH, i/2, i+1) {
-			data, err := ReadTileData(tile, storage)
-			if err != nil {
-				t.Fatal(err)
-			}
-			if !bytes.Equal(tiles[tile], data) {
-				t.Fatalf("mismatch at %+v", tile)
-			}
-		}
-
-		// Check that all the new hashes are readable from their tiles.
-		for j := oldStorage; j < len(storage); j++ {
-			tile := TileForIndex(testH, int64(j))
-			data, ok := tiles[tile]
-			if !ok {
-				t.Log(NewTiles(testH, 0, i+1))
-				t.Fatalf("TileForIndex(%d, %d) = %v, not yet stored (i=%d, stored %d)", testH, j, tile.Path(), i, len(storage))
-				continue
-			}
-			h, err := HashFromTile(tile, data, int64(j))
-			if err != nil {
-				t.Fatal(err)
-			}
-			if h != storage[j] {
-				t.Errorf("HashFromTile(%v, %d) = %v, want %v", tile.Path(), int64(j), h, storage[j])
-			}
-		}
-
-		trees = append(trees, th)
-
-		// Check that leaf proofs work, for all trees and leaves so far.
-		for j := int64(0); j <= i; j++ {
-			p, err := ProveRecord(i+1, j, storage)
-			if err != nil {
-				t.Fatalf("ProveRecord(%d, %d): %v", i+1, j, err)
-			}
-			if err := CheckRecord(p, i+1, th, j, leafhashes[j]); err != nil {
-				t.Fatalf("CheckRecord(%d, %d): %v", i+1, j, err)
-			}
-			for k := range p {
-				p[k][0] ^= 1
-				if err := CheckRecord(p, i+1, th, j, leafhashes[j]); err == nil {
-					t.Fatalf("CheckRecord(%d, %d) succeeded with corrupt proof hash #%d!", i+1, j, k)
-				}
-				p[k][0] ^= 1
-			}
-		}
-
-		// Check that leaf proofs work using TileReader.
-		// To prove a leaf that way, all you have to do is read and verify its hash.
-		storage := &testTilesStorage{m: tiles}
-		thr := TileHashReader(Tree{i + 1, th}, storage)
-		for j := int64(0); j <= i; j++ {
-			h, err := thr.ReadHashes([]int64{StoredHashIndex(0, j)})
-			if err != nil {
-				t.Fatalf("TileHashReader(%d).ReadHashes(%d): %v", i+1, j, err)
-			}
-			if h[0] != leafhashes[j] {
-				t.Fatalf("TileHashReader(%d).ReadHashes(%d) returned wrong hash", i+1, j)
-			}
-
-			// Even though reading the hash suffices,
-			// check we can generate the proof too.
-			p, err := ProveRecord(i+1, j, thr)
-			if err != nil {
-				t.Fatalf("ProveRecord(%d, %d, TileHashReader(%d)): %v", i+1, j, i+1, err)
-			}
-			if err := CheckRecord(p, i+1, th, j, leafhashes[j]); err != nil {
-				t.Fatalf("CheckRecord(%d, %d, TileHashReader(%d)): %v", i+1, j, i+1, err)
-			}
-		}
-		if storage.unsaved != 0 {
-			t.Fatalf("TileHashReader(%d) did not save %d tiles", i+1, storage.unsaved)
-		}
-
-		// Check that ReadHashes will give an error if the index is not in the tree.
-		if _, err := thr.ReadHashes([]int64{(i + 1) * 2}); err == nil {
-			t.Fatalf("TileHashReader(%d).ReadHashes(%d) for index not in tree <nil>, want err", i, i+1)
-		}
-		if storage.unsaved != 0 {
-			t.Fatalf("TileHashReader(%d) did not save %d tiles", i+1, storage.unsaved)
-		}
-
-		// Check that tree proofs work, for all trees so far, using TileReader.
-		// To prove a tree that way, all you have to do is compute and verify its hash.
-		for j := int64(0); j <= i; j++ {
-			h, err := TreeHash(j+1, thr)
-			if err != nil {
-				t.Fatalf("TreeHash(%d, TileHashReader(%d)): %v", j, i+1, err)
-			}
-			if h != trees[j] {
-				t.Fatalf("TreeHash(%d, TileHashReader(%d)) = %x, want %x (%v)", j, i+1, h[:], trees[j][:], trees[j])
-			}
-
-			// Even though computing the subtree hash suffices,
-			// check that we can generate the proof too.
-			p, err := ProveTree(i+1, j+1, thr)
-			if err != nil {
-				t.Fatalf("ProveTree(%d, %d): %v", i+1, j+1, err)
-			}
-			if err := CheckTree(p, i+1, th, j+1, trees[j]); err != nil {
-				t.Fatalf("CheckTree(%d, %d): %v [%v]", i+1, j+1, err, p)
-			}
-			for k := range p {
-				p[k][0] ^= 1
-				if err := CheckTree(p, i+1, th, j+1, trees[j]); err == nil {
-					t.Fatalf("CheckTree(%d, %d) succeeded with corrupt proof hash #%d!", i+1, j+1, k)
-				}
-				p[k][0] ^= 1
-			}
-		}
-		if storage.unsaved != 0 {
-			t.Fatalf("TileHashReader(%d) did not save %d tiles", i+1, storage.unsaved)
-		}
-	}
-}
-
-func TestSplitStoredHashIndex(t *testing.T) {
-	for l := 0; l < 10; l++ {
-		for n := int64(0); n < 100; n++ {
-			x := StoredHashIndex(l, n)
-			l1, n1 := SplitStoredHashIndex(x)
-			if l1 != l || n1 != n {
-				t.Fatalf("StoredHashIndex(%d, %d) = %d, but SplitStoredHashIndex(%d) = %d, %d", l, n, x, x, l1, n1)
-			}
-		}
-	}
-}
-
-// TODO(rsc): Test invalid paths too, like "tile/3/5/123/456/078".
-var tilePaths = []struct {
-	path string
-	tile Tile
-}{
-	{"tile/4/0/001", Tile{4, 0, 1, 16}},
-	{"tile/4/0/001.p/5", Tile{4, 0, 1, 5}},
-	{"tile/3/5/x123/x456/078", Tile{3, 5, 123456078, 8}},
-	{"tile/3/5/x123/x456/078.p/2", Tile{3, 5, 123456078, 2}},
-	{"tile/1/0/x003/x057/500", Tile{1, 0, 3057500, 2}},
-	{"tile/3/5/123/456/078", Tile{}},
-	{"tile/3/-1/123/456/078", Tile{}},
-	{"tile/1/data/x003/x057/500", Tile{1, -1, 3057500, 2}},
-}
-
-func TestTilePath(t *testing.T) {
-	for _, tt := range tilePaths {
-		if tt.tile.H > 0 {
-			p := tt.tile.Path()
-			if p != tt.path {
-				t.Errorf("%+v.Path() = %q, want %q", tt.tile, p, tt.path)
-			}
-		}
-		tile, err := ParseTilePath(tt.path)
-		if err != nil {
-			if tt.tile.H == 0 {
-				// Expected error.
-				continue
-			}
-			t.Errorf("ParseTilePath(%q): %v", tt.path, err)
-		} else if tile != tt.tile {
-			if tt.tile.H == 0 {
-				t.Errorf("ParseTilePath(%q): expected error, got %+v", tt.path, tt.tile)
-				continue
-			}
-			t.Errorf("ParseTilePath(%q) = %+v, want %+v", tt.path, tile, tt.tile)
-		}
-	}
-}

src/cmd/go/proxy_test.go

@@ -23,14 +23,15 @@ import (
 	"sync"
 	"testing"
 
-	"cmd/go/internal/dirhash"
 	"cmd/go/internal/modfetch"
 	"cmd/go/internal/modfetch/codehost"
-	"cmd/go/internal/module"
 	"cmd/go/internal/par"
-	"cmd/go/internal/semver"
-	"cmd/go/internal/sumdb"
 	"cmd/go/internal/txtar"
+
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
+	"golang.org/x/mod/sumdb"
+	"golang.org/x/mod/sumdb/dirhash"
 )
 
 var (

src/cmd/vendor/golang.org/x/crypto/ed25519/ed25519.go

+// Copyright 2016 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.
+
+// In Go 1.13, the ed25519 package was promoted to the standard library as
+// crypto/ed25519, and this package became a wrapper for the standard library one.
+//
+// +build !go1.13
+
+// Package ed25519 implements the Ed25519 signature algorithm. See
+// https://ed25519.cr.yp.to/.
+//
+// These functions are also compatible with the “Ed25519” function defined in
+// RFC 8032. However, unlike RFC 8032's formulation, this package's private key
+// representation includes a public key suffix to make multiple signing
+// operations with the same key more efficient. This package refers to the RFC
+// 8032 private key as the “seed”.
+package ed25519
+
+// This code is a port of the public domain, “ref10” implementation of ed25519
+// from SUPERCOP.
+
+import (
+	"bytes"
+	"crypto"
+	cryptorand "crypto/rand"
+	"crypto/sha512"
+	"errors"
+	"io"
+	"strconv"
+
+	"golang.org/x/crypto/ed25519/internal/edwards25519"
+)
+
+const (
+	// PublicKeySize is the size, in bytes, of public keys as used in this package.
+	PublicKeySize = 32
+	// PrivateKeySize is the size, in bytes, of private keys as used in this package.
+	PrivateKeySize = 64
+	// SignatureSize is the size, in bytes, of signatures generated and verified by this package.
+	SignatureSize = 64
+	// SeedSize is the size, in bytes, of private key seeds. These are the private key representations used by RFC 8032.
+	SeedSize = 32
+)
+
+// PublicKey is the type of Ed25519 public keys.
+type PublicKey []byte
+
+// PrivateKey is the type of Ed25519 private keys. It implements crypto.Signer.
+type PrivateKey []byte
+
+// Public returns the PublicKey corresponding to priv.
+func (priv PrivateKey) Public() crypto.PublicKey {
+	publicKey := make([]byte, PublicKeySize)
+	copy(publicKey, priv[32:])
+	return PublicKey(publicKey)
+}
+
+// Seed returns the private key seed corresponding to priv. It is provided for
+// interoperability with RFC 8032. RFC 8032's private keys correspond to seeds
+// in this package.
+func (priv PrivateKey) Seed() []byte {
+	seed := make([]byte, SeedSize)
+	copy(seed, priv[:32])
+	return seed
+}
+
+// Sign signs the given message with priv.
+// Ed25519 performs two passes over messages to be signed and therefore cannot
+// handle pre-hashed messages. Thus opts.HashFunc() must return zero to
+// indicate the message hasn't been hashed. This can be achieved by passing
+// crypto.Hash(0) as the value for opts.
+func (priv PrivateKey) Sign(rand io.Reader, message []byte, opts crypto.SignerOpts) (signature []byte, err error) {
+	if opts.HashFunc() != crypto.Hash(0) {
+		return nil, errors.New("ed25519: cannot sign hashed message")
+	}
+
+	return Sign(priv, message), nil
+}
+
+// GenerateKey generates a public/private key pair using entropy from rand.
+// If rand is nil, crypto/rand.Reader will be used.
+func GenerateKey(rand io.Reader) (PublicKey, PrivateKey, error) {
+	if rand == nil {
+		rand = cryptorand.Reader
+	}
+
+	seed := make([]byte, SeedSize)
+	if _, err := io.ReadFull(rand, seed); err != nil {
+		return nil, nil, err
+	}
+
+	privateKey := NewKeyFromSeed(seed)
+	publicKey := make([]byte, PublicKeySize)
+	copy(publicKey, privateKey[32:])
+
+	return publicKey, privateKey, nil
+}
+
+// NewKeyFromSeed calculates a private key from a seed. It will panic if
+// len(seed) is not SeedSize. This function is provided for interoperability
+// with RFC 8032. RFC 8032's private keys correspond to seeds in this
+// package.
+func NewKeyFromSeed(seed []byte) PrivateKey {
+	if l := len(seed); l != SeedSize {
+		panic("ed25519: bad seed length: " + strconv.Itoa(l))
+	}
+
+	digest := sha512.Sum512(seed)
+	digest[0] &= 248
+	digest[31] &= 127
+	digest[31] |= 64
+
+	var A edwards25519.ExtendedGroupElement
+	var hBytes [32]byte
+	copy(hBytes[:], digest[:])
+	edwards25519.GeScalarMultBase(&A, &hBytes)
+	var publicKeyBytes [32]byte
+	A.ToBytes(&publicKeyBytes)
+
+	privateKey := make([]byte, PrivateKeySize)
+	copy(privateKey, seed)
+	copy(privateKey[32:], publicKeyBytes[:])
+
+	return privateKey
+}
+
+// Sign signs the message with privateKey and returns a signature. It will
+// panic if len(privateKey) is not PrivateKeySize.
+func Sign(privateKey PrivateKey, message []byte) []byte {
+	if l := len(privateKey); l != PrivateKeySize {
+		panic("ed25519: bad private key length: " + strconv.Itoa(l))
+	}
+
+	h := sha512.New()
+	h.Write(privateKey[:32])
+
+	var digest1, messageDigest, hramDigest [64]byte
+	var expandedSecretKey [32]byte
+	h.Sum(digest1[:0])
+	copy(expandedSecretKey[:], digest1[:])
+	expandedSecretKey[0] &= 248
+	expandedSecretKey[31] &= 63
+	expandedSecretKey[31] |= 64
+
+	h.Reset()
+	h.Write(digest1[32:])
+	h.Write(message)
+	h.Sum(messageDigest[:0])
+
+	var messageDigestReduced [32]byte
+	edwards25519.ScReduce(&messageDigestReduced, &messageDigest)
+	var R edwards25519.ExtendedGroupElement
+	edwards25519.GeScalarMultBase(&R, &messageDigestReduced)
+
+	var encodedR [32]byte
+	R.ToBytes(&encodedR)
+
+	h.Reset()
+	h.Write(encodedR[:])
+	h.Write(privateKey[32:])
+	h.Write(message)
+	h.Sum(hramDigest[:0])
+	var hramDigestReduced [32]byte
+	edwards25519.ScReduce(&hramDigestReduced, &hramDigest)
+
+	var s [32]byte
+	edwards25519.ScMulAdd(&s, &hramDigestReduced, &expandedSecretKey, &messageDigestReduced)
+
+	signature := make([]byte, SignatureSize)
+	copy(signature[:], encodedR[:])
+	copy(signature[32:], s[:])
+
+	return signature
+}
+
+// Verify reports whether sig is a valid signature of message by publicKey. It
+// will panic if len(publicKey) is not PublicKeySize.
+func Verify(publicKey PublicKey, message, sig []byte) bool {
+	if l := len(publicKey); l != PublicKeySize {
+		panic("ed25519: bad public key length: " + strconv.Itoa(l))
+	}
+
+	if len(sig) != SignatureSize || sig[63]&224 != 0 {
+		return false
+	}
+
+	var A edwards25519.ExtendedGroupElement
+	var publicKeyBytes [32]byte
+	copy(publicKeyBytes[:], publicKey)
+	if !A.FromBytes(&publicKeyBytes) {
+		return false
+	}
+	edwards25519.FeNeg(&A.X, &A.X)
+	edwards25519.FeNeg(&A.T, &A.T)
+
+	h := sha512.New()
+	h.Write(sig[:32])
+	h.Write(publicKey[:])
+	h.Write(message)
+	var digest [64]byte
+	h.Sum(digest[:0])
+
+	var hReduced [32]byte
+	edwards25519.ScReduce(&hReduced, &digest)
+
+	var R edwards25519.ProjectiveGroupElement
+	var s [32]byte
+	copy(s[:], sig[32:])
+
+	// https://tools.ietf.org/html/rfc8032#section-5.1.7 requires that s be in
+	// the range [0, order) in order to prevent signature malleability.
+	if !edwards25519.ScMinimal(&s) {
+		return false
+	}
+
+	edwards25519.GeDoubleScalarMultVartime(&R, &hReduced, &A, &s)
+
+	var checkR [32]byte
+	R.ToBytes(&checkR)
+	return bytes.Equal(sig[:32], checkR[:])
+}

src/cmd/vendor/golang.org/x/crypto/ed25519/ed25519_go113.go

+// Copyright 2019 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 go1.13
+
+// Package ed25519 implements the Ed25519 signature algorithm. See
+// https://ed25519.cr.yp.to/.
+//
+// These functions are also compatible with the “Ed25519” function defined in
+// RFC 8032. However, unlike RFC 8032's formulation, this package's private key
+// representation includes a public key suffix to make multiple signing
+// operations with the same key more efficient. This package refers to the RFC
+// 8032 private key as the “seed”.
+//
+// Beginning with Go 1.13, the functionality of this package was moved to the
+// standard library as crypto/ed25519. This package only acts as a compatibility
+// wrapper.
+package ed25519
+
+import (
+	"crypto/ed25519"
+	"io"
+)
+
+const (
+	// PublicKeySize is the size, in bytes, of public keys as used in this package.
+	PublicKeySize = 32
+	// PrivateKeySize is the size, in bytes, of private keys as used in this package.
+	PrivateKeySize = 64
+	// SignatureSize is the size, in bytes, of signatures generated and verified by this package.
+	SignatureSize = 64
+	// SeedSize is the size, in bytes, of private key seeds. These are the private key representations used by RFC 8032.
+	SeedSize = 32
+)
+
+// PublicKey is the type of Ed25519 public keys.
+//
+// This type is an alias for crypto/ed25519's PublicKey type.
+// See the crypto/ed25519 package for the methods on this type.
+type PublicKey = ed25519.PublicKey
+
+// PrivateKey is the type of Ed25519 private keys. It implements crypto.Signer.
+//
+// This type is an alias for crypto/ed25519's PrivateKey type.
+// See the crypto/ed25519 package for the methods on this type.
+type PrivateKey = ed25519.PrivateKey
+
+// GenerateKey generates a public/private key pair using entropy from rand.
+// If rand is nil, crypto/rand.Reader will be used.
+func GenerateKey(rand io.Reader) (PublicKey, PrivateKey, error) {
+	return ed25519.GenerateKey(rand)
+}
+
+// NewKeyFromSeed calculates a private key from a seed. It will panic if
+// len(seed) is not SeedSize. This function is provided for interoperability
+// with RFC 8032. RFC 8032's private keys correspond to seeds in this
+// package.
+func NewKeyFromSeed(seed []byte) PrivateKey {
+	return ed25519.NewKeyFromSeed(seed)
+}
+
+// Sign signs the message with privateKey and returns a signature. It will
+// panic if len(privateKey) is not PrivateKeySize.
+func Sign(privateKey PrivateKey, message []byte) []byte {
+	return ed25519.Sign(privateKey, message)
+}
+
+// Verify reports whether sig is a valid signature of message by publicKey. It
+// will panic if len(publicKey) is not PublicKeySize.
+func Verify(publicKey PublicKey, message, sig []byte) bool {
+	return ed25519.Verify(publicKey, message, sig)
+}

src/cmd/vendor/golang.org/x/mod/LICENSE

+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

src/cmd/vendor/golang.org/x/mod/PATENTS

+Additional IP Rights Grant (Patents)
+
+"This implementation" means the copyrightable works distributed by
+Google as part of the Go project.
+
+Google hereby grants to You a perpetual, worldwide, non-exclusive,
+no-charge, royalty-free, irrevocable (except as stated in this section)
+patent license to make, have made, use, offer to sell, sell, import,
+transfer and otherwise run, modify and propagate the contents of this
+implementation of Go, where such license applies only to those patent
+claims, both currently owned or controlled by Google and acquired in
+the future, licensable by Google that are necessarily infringed by this
+implementation of Go.  This grant does not include claims that would be
+infringed only as a consequence of further modification of this
+implementation.  If you or your agent or exclusive licensee institute or
+order or agree to the institution of patent litigation against any
+entity (including a cross-claim or counterclaim in a lawsuit) alleging
+that this implementation of Go or any code incorporated within this
+implementation of Go constitutes direct or contributory patent
+infringement, or inducement of patent infringement, then any patent
+rights granted to you under this License for this implementation of Go
+shall terminate as of the date such litigation is filed.

src/cmd/vendor/golang.org/x/mod/internal/lazyregexp/lazyre.go

+// 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.
+
+// Package lazyregexp is a thin wrapper over regexp, allowing the use of global
+// regexp variables without forcing them to be compiled at init.
+package lazyregexp
+
+import (
+	"os"
+	"regexp"
+	"strings"
+	"sync"
+)
+
+// Regexp is a wrapper around regexp.Regexp, where the underlying regexp will be
+// compiled the first time it is needed.
+type Regexp struct {
+	str  string
+	once sync.Once
+	rx   *regexp.Regexp
+}
+
+func (r *Regexp) re() *regexp.Regexp {
+	r.once.Do(r.build)
+	return r.rx
+}
+
+func (r *Regexp) build() {
+	r.rx = regexp.MustCompile(r.str)
+	r.str = ""
+}
+
+func (r *Regexp) FindSubmatch(s []byte) [][]byte {
+	return r.re().FindSubmatch(s)
+}
+
+func (r *Regexp) FindStringSubmatch(s string) []string {
+	return r.re().FindStringSubmatch(s)
+}
+
+func (r *Regexp) FindStringSubmatchIndex(s string) []int {
+	return r.re().FindStringSubmatchIndex(s)
+}
+
+func (r *Regexp) ReplaceAllString(src, repl string) string {
+	return r.re().ReplaceAllString(src, repl)
+}
+
+func (r *Regexp) FindString(s string) string {
+	return r.re().FindString(s)
+}
+
+func (r *Regexp) FindAllString(s string, n int) []string {
+	return r.re().FindAllString(s, n)
+}
+
+func (r *Regexp) MatchString(s string) bool {
+	return r.re().MatchString(s)
+}
+
+func (r *Regexp) SubexpNames() []string {
+	return r.re().SubexpNames()
+}
+
+var inTest = len(os.Args) > 0 && strings.HasSuffix(strings.TrimSuffix(os.Args[0], ".exe"), ".test")
+
+// New creates a new lazy regexp, delaying the compiling work until it is first
+// needed. If the code is being run as part of tests, the regexp compiling will
+// happen immediately.
+func New(str string) *Regexp {
+	lr := &Regexp{str: str}
+	if inTest {
+		// In tests, always compile the regexps early.
+		lr.re()
+	}
+	return lr
+}

src/cmd/go/internal/modfile/rule.go → src/cmd/vendor/golang.org/x/mod/modfile/rule.go

@@ -8,14 +8,14 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
-	"internal/lazyregexp"
 	"path/filepath"
 	"sort"
 	"strconv"
 	"strings"
 	"unicode"
 
-	"cmd/go/internal/module"
+	"golang.org/x/mod/internal/lazyregexp"
+	"golang.org/x/mod/module"
 )
 
 // A File is the parsed, interpreted form of a go.mod file.

src/cmd/go/internal/module/module.go → src/cmd/vendor/golang.org/x/mod/module/module.go

@@ -96,14 +96,14 @@ package module
 // Changes to the semantics in this file require approval from rsc.
 
 import (
-	"errors"
 	"fmt"
 	"sort"
 	"strings"
 	"unicode"
 	"unicode/utf8"
 
-	"cmd/go/internal/semver"
+	"golang.org/x/mod/semver"
+	errors "golang.org/x/xerrors"
 )
 
 // A Version (for clients, a module.Version) is defined by a module path and version pair.

src/cmd/go/internal/sumdb/client.go → src/cmd/vendor/golang.org/x/mod/sumdb/client.go

@@ -13,9 +13,9 @@ import (
 	"sync"
 	"sync/atomic"
 
-	"cmd/go/internal/module"
-	"cmd/go/internal/note"
-	"cmd/go/internal/tlog"
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/sumdb/note"
+	"golang.org/x/mod/sumdb/tlog"
 )
 
 // A ClientOps provides the external operations

src/cmd/go/internal/note/note.go → src/cmd/vendor/golang.org/x/mod/sumdb/note/note.go

@@ -183,7 +183,6 @@ package note
 
 import (
 	"bytes"
-	"crypto/ed25519"
 	"crypto/sha256"
 	"encoding/base64"
 	"encoding/binary"
@@ -194,6 +193,8 @@ import (
 	"strings"
 	"unicode"
 	"unicode/utf8"
+
+	"golang.org/x/crypto/ed25519"
 )
 
 // A Verifier verifies messages signed with a specific key.

src/cmd/go/internal/sumdb/server.go → src/cmd/vendor/golang.org/x/mod/sumdb/server.go

@@ -7,13 +7,13 @@ package sumdb
 
 import (
 	"context"
-	"internal/lazyregexp"
 	"net/http"
 	"os"
 	"strings"
 
-	"cmd/go/internal/module"
-	"cmd/go/internal/tlog"
+	"golang.org/x/mod/internal/lazyregexp"
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/sumdb/tlog"
 )
 
 // A ServerOps provides the external operations

src/cmd/go/internal/sumdb/test.go → src/cmd/vendor/golang.org/x/mod/sumdb/test.go

@@ -9,9 +9,9 @@ import (
 	"fmt"
 	"sync"
 
-	"cmd/go/internal/module"
-	"cmd/go/internal/note"
-	"cmd/go/internal/tlog"
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/sumdb/note"
+	"golang.org/x/mod/sumdb/tlog"
 )
 
 // NewTestServer constructs a new TestServer

src/cmd/vendor/golang.org/x/xerrors/LICENSE

+Copyright (c) 2019 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

src/cmd/vendor/golang.org/x/xerrors/PATENTS

+Additional IP Rights Grant (Patents)
+
+"This implementation" means the copyrightable works distributed by
+Google as part of the Go project.
+
+Google hereby grants to You a perpetual, worldwide, non-exclusive,
+no-charge, royalty-free, irrevocable (except as stated in this section)
+patent license to make, have made, use, offer to sell, sell, import,
+transfer and otherwise run, modify and propagate the contents of this
+implementation of Go, where such license applies only to those patent
+claims, both currently owned or controlled by Google and acquired in
+the future, licensable by Google that are necessarily infringed by this
+implementation of Go.  This grant does not include claims that would be
+infringed only as a consequence of further modification of this
+implementation.  If you or your agent or exclusive licensee institute or
+order or agree to the institution of patent litigation against any
+entity (including a cross-claim or counterclaim in a lawsuit) alleging
+that this implementation of Go or any code incorporated within this
+implementation of Go constitutes direct or contributory patent
+infringement, or inducement of patent infringement, then any patent
+rights granted to you under this License for this implementation of Go
+shall terminate as of the date such litigation is filed.

src/cmd/vendor/golang.org/x/xerrors/README

+This repository holds the transition packages for the new Go 1.13 error values.
+See golang.org/design/29934-error-values.

src/cmd/vendor/golang.org/x/xerrors/adaptor.go

+// 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.
+
+package xerrors
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"reflect"
+	"strconv"
+)
+
+// FormatError calls the FormatError method of f with an errors.Printer
+// configured according to s and verb, and writes the result to s.
+func FormatError(f Formatter, s fmt.State, verb rune) {
+	// Assuming this function is only called from the Format method, and given
+	// that FormatError takes precedence over Format, it cannot be called from
+	// any package that supports errors.Formatter. It is therefore safe to
+	// disregard that State may be a specific printer implementation and use one
+	// of our choice instead.
+
+	// limitations: does not support printing error as Go struct.
+
+	var (
+		sep    = " " // separator before next error
+		p      = &state{State: s}
+		direct = true
+	)
+
+	var err error = f
+
+	switch verb {
+	// Note that this switch must match the preference order
+	// for ordinary string printing (%#v before %+v, and so on).
+
+	case 'v':
+		if s.Flag('#') {
+			if stringer, ok := err.(fmt.GoStringer); ok {
+				io.WriteString(&p.buf, stringer.GoString())
+				goto exit
+			}
+			// proceed as if it were %v
+		} else if s.Flag('+') {
+			p.printDetail = true
+			sep = "\n  - "
+		}
+	case 's':
+	case 'q', 'x', 'X':
+		// Use an intermediate buffer in the rare cases that precision,
+		// truncation, or one of the alternative verbs (q, x, and X) are
+		// specified.
+		direct = false
+
+	default:
+		p.buf.WriteString("%!")
+		p.buf.WriteRune(verb)
+		p.buf.WriteByte('(')
+		switch {
+		case err != nil:
+			p.buf.WriteString(reflect.TypeOf(f).String())
+		default:
+			p.buf.WriteString("<nil>")
+		}
+		p.buf.WriteByte(')')
+		io.Copy(s, &p.buf)
+		return
+	}
+
+loop:
+	for {
+		switch v := err.(type) {
+		case Formatter:
+			err = v.FormatError((*printer)(p))
+		case fmt.Formatter:
+			v.Format(p, 'v')
+			break loop
+		default:
+			io.WriteString(&p.buf, v.Error())
+			break loop
+		}
+		if err == nil {
+			break
+		}
+		if p.needColon || !p.printDetail {
+			p.buf.WriteByte(':')
+			p.needColon = false
+		}
+		p.buf.WriteString(sep)
+		p.inDetail = false
+		p.needNewline = false
+	}
+
+exit:
+	width, okW := s.Width()
+	prec, okP := s.Precision()
+
+	if !direct || (okW && width > 0) || okP {
+		// Construct format string from State s.
+		format := []byte{'%'}
+		if s.Flag('-') {
+			format = append(format, '-')
+		}
+		if s.Flag('+') {
+			format = append(format, '+')
+		}
+		if s.Flag(' ') {
+			format = append(format, ' ')
+		}
+		if okW {
+			format = strconv.AppendInt(format, int64(width), 10)
+		}
+		if okP {
+			format = append(format, '.')
+			format = strconv.AppendInt(format, int64(prec), 10)
+		}
+		format = append(format, string(verb)...)
+		fmt.Fprintf(s, string(format), p.buf.String())
+	} else {
+		io.Copy(s, &p.buf)
+	}
+}
+
+var detailSep = []byte("\n    ")
+
+// state tracks error printing state. It implements fmt.State.
+type state struct {
+	fmt.State
+	buf bytes.Buffer
+
+	printDetail bool
+	inDetail    bool
+	needColon   bool
+	needNewline bool
+}
+
+func (s *state) Write(b []byte) (n int, err error) {
+	if s.printDetail {
+		if len(b) == 0 {
+			return 0, nil
+		}
+		if s.inDetail && s.needColon {
+			s.needNewline = true
+			if b[0] == '\n' {
+				b = b[1:]
+			}
+		}
+		k := 0
+		for i, c := range b {
+			if s.needNewline {
+				if s.inDetail && s.needColon {
+					s.buf.WriteByte(':')
+					s.needColon = false
+				}
+				s.buf.Write(detailSep)
+				s.needNewline = false
+			}
+			if c == '\n' {
+				s.buf.Write(b[k:i])
+				k = i + 1
+				s.needNewline = true
+			}
+		}
+		s.buf.Write(b[k:])
+		if !s.inDetail {
+			s.needColon = true
+		}
+	} else if !s.inDetail {
+		s.buf.Write(b)
+	}
+	return len(b), nil
+}
+
+// printer wraps a state to implement an xerrors.Printer.
+type printer state
+
+func (s *printer) Print(args ...interface{}) {
+	if !s.inDetail || s.printDetail {
+		fmt.Fprint((*state)(s), args...)
+	}
+}
+
+func (s *printer) Printf(format string, args ...interface{}) {
+	if !s.inDetail || s.printDetail {
+		fmt.Fprintf((*state)(s), format, args...)
+	}
+}
+
+func (s *printer) Detail() bool {
+	s.inDetail = true
+	return s.printDetail
+}

src/cmd/vendor/golang.org/x/xerrors/codereview.cfg

+issuerepo: golang/go

src/cmd/vendor/golang.org/x/xerrors/doc.go

+// Copyright 2019 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.
+
+// Package xerrors implements functions to manipulate errors.
+//
+// This package is based on the Go 2 proposal for error values:
+//   https://golang.org/design/29934-error-values
+//
+// These functions were incorporated into the standard library's errors package
+// in Go 1.13:
+// - Is
+// - As
+// - Unwrap
+//
+// Also, Errorf's %w verb was incorporated into fmt.Errorf.
+//
+// Use this package to get equivalent behavior in all supported Go versions.
+//
+// No other features of this package were included in Go 1.13, and at present
+// there are no plans to include any of them.
+package xerrors // import "golang.org/x/xerrors"

src/cmd/vendor/golang.org/x/xerrors/errors.go

+// Copyright 2011 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.
+
+package xerrors
+
+import "fmt"
+
+// errorString is a trivial implementation of error.
+type errorString struct {
+	s     string
+	frame Frame
+}
+
+// New returns an error that formats as the given text.
+//
+// The returned error contains a Frame set to the caller's location and
+// implements Formatter to show this information when printed with details.
+func New(text string) error {
+	return &errorString{text, Caller(1)}
+}
+
+func (e *errorString) Error() string {
+	return e.s
+}
+
+func (e *errorString) Format(s fmt.State, v rune) { FormatError(e, s, v) }
+
+func (e *errorString) FormatError(p Printer) (next error) {
+	p.Print(e.s)
+	e.frame.Format(p)
+	return nil
+}

src/cmd/vendor/golang.org/x/xerrors/fmt.go

+// 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.
+
+package xerrors
+
+import (
+	"fmt"
+	"strings"
+
+	"golang.org/x/xerrors/internal"
+)
+
+// Errorf formats according to a format specifier and returns the string as a
+// value that satisfies error.
+//
+// The returned error includes the file and line number of the caller when
+// formatted with additional detail enabled. If the last argument is an error
+// the returned error's Format method will return it if the format string ends
+// with ": %s", ": %v", or ": %w". If the last argument is an error and the
+// format string ends with ": %w", the returned error implements Wrapper
+// with an Unwrap method returning it.
+func Errorf(format string, a ...interface{}) error {
+	err, wrap := lastError(format, a)
+	format = formatPlusW(format)
+	if err == nil {
+		return &noWrapError{fmt.Sprintf(format, a...), nil, Caller(1)}
+	}
+
+	// TODO: this is not entirely correct. The error value could be
+	// printed elsewhere in format if it mixes numbered with unnumbered
+	// substitutions. With relatively small changes to doPrintf we can
+	// have it optionally ignore extra arguments and pass the argument
+	// list in its entirety.
+	msg := fmt.Sprintf(format[:len(format)-len(": %s")], a[:len(a)-1]...)
+	frame := Frame{}
+	if internal.EnableTrace {
+		frame = Caller(1)
+	}
+	if wrap {
+		return &wrapError{msg, err, frame}
+	}
+	return &noWrapError{msg, err, frame}
+}
+
+// formatPlusW is used to avoid the vet check that will barf at %w.
+func formatPlusW(s string) string {
+	return s
+}
+
+func lastError(format string, a []interface{}) (err error, wrap bool) {
+	wrap = strings.HasSuffix(format, ": %w")
+	if !wrap &&
+		!strings.HasSuffix(format, ": %s") &&
+		!strings.HasSuffix(format, ": %v") {
+		return nil, false
+	}
+
+	if len(a) == 0 {
+		return nil, false
+	}
+
+	err, ok := a[len(a)-1].(error)
+	if !ok {
+		return nil, false
+	}
+
+	return err, wrap
+}
+
+type noWrapError struct {
+	msg   string
+	err   error
+	frame Frame
+}
+
+func (e *noWrapError) Error() string {
+	return fmt.Sprint(e)
+}
+
+func (e *noWrapError) Format(s fmt.State, v rune) { FormatError(e, s, v) }
+
+func (e *noWrapError) FormatError(p Printer) (next error) {
+	p.Print(e.msg)
+	e.frame.Format(p)
+	return e.err
+}
+
+type wrapError struct {
+	msg   string
+	err   error
+	frame Frame
+}
+
+func (e *wrapError) Error() string {
+	return fmt.Sprint(e)
+}
+
+func (e *wrapError) Format(s fmt.State, v rune) { FormatError(e, s, v) }
+
+func (e *wrapError) FormatError(p Printer) (next error) {
+	p.Print(e.msg)
+	e.frame.Format(p)
+	return e.err
+}
+
+func (e *wrapError) Unwrap() error {
+	return e.err
+}

src/cmd/vendor/golang.org/x/xerrors/format.go

+// 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.
+
+package xerrors
+
+// A Formatter formats error messages.
+type Formatter interface {
+	error
+
+	// FormatError prints the receiver's first error and returns the next error in
+	// the error chain, if any.
+	FormatError(p Printer) (next error)
+}
+
+// A Printer formats error messages.
+//
+// The most common implementation of Printer is the one provided by package fmt
+// during Printf (as of Go 1.13). Localization packages such as golang.org/x/text/message
+// typically provide their own implementations.
+type Printer interface {
+	// Print appends args to the message output.
+	Print(args ...interface{})
+
+	// Printf writes a formatted string.
+	Printf(format string, args ...interface{})
+
+	// Detail reports whether error detail is requested.
+	// After the first call to Detail, all text written to the Printer
+	// is formatted as additional detail, or ignored when
+	// detail has not been requested.
+	// If Detail returns false, the caller can avoid printing the detail at all.
+	Detail() bool
+}

src/cmd/vendor/golang.org/x/xerrors/frame.go

+// 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.
+
+package xerrors
+
+import (
+	"runtime"
+)
+
+// A Frame contains part of a call stack.
+type Frame struct {
+	// Make room for three PCs: the one we were asked for, what it called,
+	// and possibly a PC for skipPleaseUseCallersFrames. See:
+	// https://go.googlesource.com/go/+/032678e0fb/src/runtime/extern.go#169
+	frames [3]uintptr
+}
+
+// Caller returns a Frame that describes a frame on the caller's stack.
+// The argument skip is the number of frames to skip over.
+// Caller(0) returns the frame for the caller of Caller.
+func Caller(skip int) Frame {
+	var s Frame
+	runtime.Callers(skip+1, s.frames[:])
+	return s
+}
+
+// location reports the file, line, and function of a frame.
+//
+// The returned function may be "" even if file and line are not.
+func (f Frame) location() (function, file string, line int) {
+	frames := runtime.CallersFrames(f.frames[:])
+	if _, ok := frames.Next(); !ok {
+		return "", "", 0
+	}
+	fr, ok := frames.Next()
+	if !ok {
+		return "", "", 0
+	}
+	return fr.Function, fr.File, fr.Line
+}
+
+// Format prints the stack as error detail.
+// It should be called from an error's Format implementation
+// after printing any other error detail.
+func (f Frame) Format(p Printer) {
+	if p.Detail() {
+		function, file, line := f.location()
+		if function != "" {
+			p.Printf("%s\n    ", function)
+		}
+		if file != "" {
+			p.Printf("%s:%d\n", file, line)
+		}
+	}
+}