1 files changed, 505 insertions, 0 deletions
diff --git a/src/cmd/go/internal/modcmd/edit.go b/src/cmd/go/internal/modcmd/edit.go
new file mode 100644
index 0000000..1df104e
--- /dev/null
+++ b/src/cmd/go/internal/modcmd/edit.go
@@ -0,0 +1,505 @@
+// 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.
+
+// go mod edit
+
+package modcmd
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+
+	"cmd/go/internal/base"
+	"cmd/go/internal/lockedfile"
+	"cmd/go/internal/modfetch"
+	"cmd/go/internal/modload"
+
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
+)
+
+var cmdEdit = &base.Command{
+	UsageLine: "go mod edit [editing flags] [go.mod]",
+	Short:     "edit go.mod from tools or scripts",
+	Long: `
+Edit provides a command-line interface for editing go.mod,
+for use primarily by tools or scripts. It reads only go.mod;
+it does not look up information about the modules involved.
+By default, edit reads and writes the go.mod file of the main module,
+but a different target file can be specified after the editing flags.
+
+The editing flags specify a sequence of editing operations.
+
+The -fmt flag reformats the go.mod file without making other changes.
+This reformatting is also implied by any other modifications that use or
+rewrite the go.mod file. The only time this flag is needed is if no other
+flags are specified, as in 'go mod edit -fmt'.
+
+The -module flag changes the module's path (the go.mod file's module line).
+
+The -require=path@version and -droprequire=path flags
+add and drop a requirement on the given module path and version.
+Note that -require overrides any existing requirements on path.
+These flags are mainly for tools that understand the module graph.
+Users should prefer 'go get path@version' or 'go get path@none',
+which make other go.mod adjustments as needed to satisfy
+constraints imposed by other modules.
+
+The -exclude=path@version and -dropexclude=path@version flags
+add and drop an exclusion for the given module path and version.
+Note that -exclude=path@version is a no-op if that exclusion already exists.
+
+The -replace=old[@v]=new[@v] flag adds a replacement of the given
+module path and version pair. If the @v in old@v is omitted, a
+replacement without a version on the left side is added, which applies
+to all versions of the old module path. If the @v in new@v is omitted,
+the new path should be a local module root directory, not a module
+path. Note that -replace overrides any redundant replacements for old[@v],
+so omitting @v will drop existing replacements for specific versions.
+
+The -dropreplace=old[@v] flag drops a replacement of the given
+module path and version pair. If the @v is omitted, a replacement without
+a version on the left side is dropped.
+
+The -retract=version and -dropretract=version flags add and drop a
+retraction on the given version. The version may be a single version
+like "v1.2.3" or a closed interval like "[v1.1.0,v1.1.9]". Note that
+-retract=version is a no-op if that retraction already exists.
+
+The -require, -droprequire, -exclude, -dropexclude, -replace,
+-dropreplace, -retract, and -dropretract editing flags may be repeated,
+and the changes are applied in the order given.
+
+The -go=version flag sets the expected Go language version.
+
+The -print flag prints the final go.mod in its text format instead of
+writing it back to go.mod.
+
+The -json flag prints the final go.mod file in JSON format instead of
+writing it back to go.mod. The JSON output corresponds to these Go types:
+
+	type Module struct {
+		Path string
+		Version string
+	}
+
+	type GoMod struct {
+		Module  Module
+		Go      string
+		Require []Require
+		Exclude []Module
+		Replace []Replace
+		Retract []Retract
+	}
+
+	type Require struct {
+		Path string
+		Version string
+		Indirect bool
+	}
+
+	type Replace struct {
+		Old Module
+		New Module
+	}
+
+	type Retract struct {
+		Low       string
+		High      string
+		Rationale string
+	}
+
+Retract entries representing a single version (not an interval) will have
+the "Low" and "High" fields set to the same value.
+
+Note that this only describes the go.mod file itself, not other modules
+referred to indirectly. For the full set of modules available to a build,
+use 'go list -m -json all'.
+
+See https://golang.org/ref/mod#go-mod-edit for more about 'go mod edit'.
+	`,
+}
+
+var (
+	editFmt    = cmdEdit.Flag.Bool("fmt", false, "")
+	editGo     = cmdEdit.Flag.String("go", "", "")
+	editJSON   = cmdEdit.Flag.Bool("json", false, "")
+	editPrint  = cmdEdit.Flag.Bool("print", false, "")
+	editModule = cmdEdit.Flag.String("module", "", "")
+	edits      []func(*modfile.File) // edits specified in flags
+)
+
+type flagFunc func(string)
+
+func (f flagFunc) String() string     { return "" }
+func (f flagFunc) Set(s string) error { f(s); return nil }
+
+func init() {
+	cmdEdit.Run = runEdit // break init cycle
+
+	cmdEdit.Flag.Var(flagFunc(flagRequire), "require", "")
+	cmdEdit.Flag.Var(flagFunc(flagDropRequire), "droprequire", "")
+	cmdEdit.Flag.Var(flagFunc(flagExclude), "exclude", "")
+	cmdEdit.Flag.Var(flagFunc(flagDropReplace), "dropreplace", "")
+	cmdEdit.Flag.Var(flagFunc(flagReplace), "replace", "")
+	cmdEdit.Flag.Var(flagFunc(flagDropExclude), "dropexclude", "")
+	cmdEdit.Flag.Var(flagFunc(flagRetract), "retract", "")
+	cmdEdit.Flag.Var(flagFunc(flagDropRetract), "dropretract", "")
+
+	base.AddModCommonFlags(&cmdEdit.Flag)
+	base.AddBuildFlagsNX(&cmdEdit.Flag)
+}
+
+func runEdit(ctx context.Context, cmd *base.Command, args []string) {
+	anyFlags :=
+		*editModule != "" ||
+			*editGo != "" ||
+			*editJSON ||
+			*editPrint ||
+			*editFmt ||
+			len(edits) > 0
+
+	if !anyFlags {
+		base.Fatalf("go mod edit: no flags specified (see 'go help mod edit').")
+	}
+
+	if *editJSON && *editPrint {
+		base.Fatalf("go mod edit: cannot use both -json and -print")
+	}
+
+	if len(args) > 1 {
+		base.Fatalf("go mod edit: too many arguments")
+	}
+	var gomod string
+	if len(args) == 1 {
+		gomod = args[0]
+	} else {
+		gomod = modload.ModFilePath()
+	}
+
+	if *editModule != "" {
+		if err := module.CheckImportPath(*editModule); err != nil {
+			base.Fatalf("go mod: invalid -module: %v", err)
+		}
+	}
+
+	if *editGo != "" {
+		if !modfile.GoVersionRE.MatchString(*editGo) {
+			base.Fatalf(`go mod: invalid -go option; expecting something like "-go 1.12"`)
+		}
+	}
+
+	data, err := lockedfile.Read(gomod)
+	if err != nil {
+		base.Fatalf("go: %v", err)
+	}
+
+	modFile, err := modfile.Parse(gomod, data, nil)
+	if err != nil {
+		base.Fatalf("go: errors parsing %s:\n%s", base.ShortPath(gomod), err)
+	}
+
+	if *editModule != "" {
+		modFile.AddModuleStmt(*editModule)
+	}
+
+	if *editGo != "" {
+		if err := modFile.AddGoStmt(*editGo); err != nil {
+			base.Fatalf("go: internal error: %v", err)
+		}
+	}
+
+	if len(edits) > 0 {
+		for _, edit := range edits {
+			edit(modFile)
+		}
+	}
+	modFile.SortBlocks()
+	modFile.Cleanup() // clean file after edits
+
+	if *editJSON {
+		editPrintJSON(modFile)
+		return
+	}
+
+	out, err := modFile.Format()
+	if err != nil {
+		base.Fatalf("go: %v", err)
+	}
+
+	if *editPrint {
+		os.Stdout.Write(out)
+		return
+	}
+
+	// Make a best-effort attempt to acquire the side lock, only to exclude
+	// previous versions of the 'go' command from making simultaneous edits.
+	if unlock, err := modfetch.SideLock(); err == nil {
+		defer unlock()
+	}
+
+	err = lockedfile.Transform(gomod, func(lockedData []byte) ([]byte, error) {
+		if !bytes.Equal(lockedData, data) {
+			return nil, errors.New("go.mod changed during editing; not overwriting")
+		}
+		return out, nil
+	})
+	if err != nil {
+		base.Fatalf("go: %v", err)
+	}
+}
+
+// parsePathVersion parses -flag=arg expecting arg to be path@version.
+func parsePathVersion(flag, arg string) (path, version string) {
+	i := strings.Index(arg, "@")
+	if i < 0 {
+		base.Fatalf("go mod: -%s=%s: need path@version", flag, arg)
+	}
+	path, version = strings.TrimSpace(arg[:i]), strings.TrimSpace(arg[i+1:])
+	if err := module.CheckImportPath(path); err != nil {
+		base.Fatalf("go mod: -%s=%s: invalid path: %v", flag, arg, err)
+	}
+
+	if !allowedVersionArg(version) {
+		base.Fatalf("go mod: -%s=%s: invalid version %q", flag, arg, version)
+	}
+
+	return path, version
+}
+
+// parsePath parses -flag=arg expecting arg to be path (not path@version).
+func parsePath(flag, arg string) (path string) {
+	if strings.Contains(arg, "@") {
+		base.Fatalf("go mod: -%s=%s: need just path, not path@version", flag, arg)
+	}
+	path = arg
+	if err := module.CheckImportPath(path); err != nil {
+		base.Fatalf("go mod: -%s=%s: invalid path: %v", flag, arg, err)
+	}
+	return path
+}
+
+// parsePathVersionOptional parses path[@version], using adj to
+// describe any errors.
+func parsePathVersionOptional(adj, arg string, allowDirPath bool) (path, version string, err error) {
+	if i := strings.Index(arg, "@"); i < 0 {
+		path = arg
+	} else {
+		path, version = strings.TrimSpace(arg[:i]), strings.TrimSpace(arg[i+1:])
+	}
+	if err := module.CheckImportPath(path); err != nil {
+		if !allowDirPath || !modfile.IsDirectoryPath(path) {
+			return path, version, fmt.Errorf("invalid %s path: %v", adj, err)
+		}
+	}
+	if path != arg && !allowedVersionArg(version) {
+		return path, version, fmt.Errorf("invalid %s version: %q", adj, version)
+	}
+	return path, version, nil
+}
+
+// parseVersionInterval parses a single version like "v1.2.3" or a closed
+// interval like "[v1.2.3,v1.4.5]". Note that a single version has the same
+// representation as an interval with equal upper and lower bounds: both
+// Low and High are set.
+func parseVersionInterval(arg string) (modfile.VersionInterval, error) {
+	if !strings.HasPrefix(arg, "[") {
+		if !allowedVersionArg(arg) {
+			return modfile.VersionInterval{}, fmt.Errorf("invalid version: %q", arg)
+		}
+		return modfile.VersionInterval{Low: arg, High: arg}, nil
+	}
+	if !strings.HasSuffix(arg, "]") {
+		return modfile.VersionInterval{}, fmt.Errorf("invalid version interval: %q", arg)
+	}
+	s := arg[1 : len(arg)-1]
+	i := strings.Index(s, ",")
+	if i < 0 {
+		return modfile.VersionInterval{}, fmt.Errorf("invalid version interval: %q", arg)
+	}
+	low := strings.TrimSpace(s[:i])
+	high := strings.TrimSpace(s[i+1:])
+	if !allowedVersionArg(low) || !allowedVersionArg(high) {
+		return modfile.VersionInterval{}, fmt.Errorf("invalid version interval: %q", arg)
+	}
+	return modfile.VersionInterval{Low: low, High: high}, nil
+}
+
+// allowedVersionArg returns whether a token may be used as a version in go.mod.
+// We don't call modfile.CheckPathVersion, because that insists on versions
+// being in semver form, but here we want to allow versions like "master" or
+// "1234abcdef", which the go command will resolve the next time it runs (or
+// during -fix).  Even so, we need to make sure the version is a valid token.
+func allowedVersionArg(arg string) bool {
+	return !modfile.MustQuote(arg)
+}
+
+// flagRequire implements the -require flag.
+func flagRequire(arg string) {
+	path, version := parsePathVersion("require", arg)
+	edits = append(edits, func(f *modfile.File) {
+		if err := f.AddRequire(path, version); err != nil {
+			base.Fatalf("go mod: -require=%s: %v", arg, err)
+		}
+	})
+}
+
+// flagDropRequire implements the -droprequire flag.
+func flagDropRequire(arg string) {
+	path := parsePath("droprequire", arg)
+	edits = append(edits, func(f *modfile.File) {
+		if err := f.DropRequire(path); err != nil {
+			base.Fatalf("go mod: -droprequire=%s: %v", arg, err)
+		}
+	})
+}
+
+// flagExclude implements the -exclude flag.
+func flagExclude(arg string) {
+	path, version := parsePathVersion("exclude", arg)
+	edits = append(edits, func(f *modfile.File) {
+		if err := f.AddExclude(path, version); err != nil {
+			base.Fatalf("go mod: -exclude=%s: %v", arg, err)
+		}
+	})
+}
+
+// flagDropExclude implements the -dropexclude flag.
+func flagDropExclude(arg string) {
+	path, version := parsePathVersion("dropexclude", arg)
+	edits = append(edits, func(f *modfile.File) {
+		if err := f.DropExclude(path, version); err != nil {
+			base.Fatalf("go mod: -dropexclude=%s: %v", arg, err)
+		}
+	})
+}
+
+// flagReplace implements the -replace flag.
+func flagReplace(arg string) {
+	var i int
+	if i = strings.Index(arg, "="); i < 0 {
+		base.Fatalf("go mod: -replace=%s: need old[@v]=new[@w] (missing =)", arg)
+	}
+	old, new := strings.TrimSpace(arg[:i]), strings.TrimSpace(arg[i+1:])
+	if strings.HasPrefix(new, ">") {
+		base.Fatalf("go mod: -replace=%s: separator between old and new is =, not =>", arg)
+	}
+	oldPath, oldVersion, err := parsePathVersionOptional("old", old, false)
+	if err != nil {
+		base.Fatalf("go mod: -replace=%s: %v", arg, err)
+	}
+	newPath, newVersion, err := parsePathVersionOptional("new", new, true)
+	if err != nil {
+		base.Fatalf("go mod: -replace=%s: %v", arg, err)
+	}
+	if newPath == new && !modfile.IsDirectoryPath(new) {
+		base.Fatalf("go mod: -replace=%s: unversioned new path must be local directory", arg)
+	}
+
+	edits = append(edits, func(f *modfile.File) {
+		if err := f.AddReplace(oldPath, oldVersion, newPath, newVersion); err != nil {
+			base.Fatalf("go mod: -replace=%s: %v", arg, err)
+		}
+	})
+}
+
+// flagDropReplace implements the -dropreplace flag.
+func flagDropReplace(arg string) {
+	path, version, err := parsePathVersionOptional("old", arg, true)
+	if err != nil {
+		base.Fatalf("go mod: -dropreplace=%s: %v", arg, err)
+	}
+	edits = append(edits, func(f *modfile.File) {
+		if err := f.DropReplace(path, version); err != nil {
+			base.Fatalf("go mod: -dropreplace=%s: %v", arg, err)
+		}
+	})
+}
+
+// flagRetract implements the -retract flag.
+func flagRetract(arg string) {
+	vi, err := parseVersionInterval(arg)
+	if err != nil {
+		base.Fatalf("go mod: -retract=%s: %v", arg, err)
+	}
+	edits = append(edits, func(f *modfile.File) {
+		if err := f.AddRetract(vi, ""); err != nil {
+			base.Fatalf("go mod: -retract=%s: %v", arg, err)
+		}
+	})
+}
+
+// flagDropRetract implements the -dropretract flag.
+func flagDropRetract(arg string) {
+	vi, err := parseVersionInterval(arg)
+	if err != nil {
+		base.Fatalf("go mod: -dropretract=%s: %v", arg, err)
+	}
+	edits = append(edits, func(f *modfile.File) {
+		if err := f.DropRetract(vi); err != nil {
+			base.Fatalf("go mod: -dropretract=%s: %v", arg, err)
+		}
+	})
+}
+
+// fileJSON is the -json output data structure.
+type fileJSON struct {
+	Module  module.Version
+	Go      string `json:",omitempty"`
+	Require []requireJSON
+	Exclude []module.Version
+	Replace []replaceJSON
+	Retract []retractJSON
+}
+
+type requireJSON struct {
+	Path     string
+	Version  string `json:",omitempty"`
+	Indirect bool   `json:",omitempty"`
+}
+
+type replaceJSON struct {
+	Old module.Version
+	New module.Version
+}
+
+type retractJSON struct {
+	Low       string `json:",omitempty"`
+	High      string `json:",omitempty"`
+	Rationale string `json:",omitempty"`
+}
+
+// editPrintJSON prints the -json output.
+func editPrintJSON(modFile *modfile.File) {
+	var f fileJSON
+	if modFile.Module != nil {
+		f.Module = modFile.Module.Mod
+	}
+	if modFile.Go != nil {
+		f.Go = modFile.Go.Version
+	}
+	for _, r := range modFile.Require {
+		f.Require = append(f.Require, requireJSON{Path: r.Mod.Path, Version: r.Mod.Version, Indirect: r.Indirect})
+	}
+	for _, x := range modFile.Exclude {
+		f.Exclude = append(f.Exclude, x.Mod)
+	}
+	for _, r := range modFile.Replace {
+		f.Replace = append(f.Replace, replaceJSON{r.Old, r.New})
+	}
+	for _, r := range modFile.Retract {
+		f.Retract = append(f.Retract, retractJSON{r.Low, r.High, r.Rationale})
+	}
+	data, err := json.MarshalIndent(&f, "", "\t")
+	if err != nil {
+		base.Fatalf("go: internal error: %v", err)
+	}
+	data = append(data, '\n')
+	os.Stdout.Write(data)
+}