blob: 1cd8d8473e993ef18e5188df9a393f90fe12c6e0 [file] [log] [blame]
// Copyright 2020 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 gocommand
import (
// ModuleJSON holds information about a module.
type ModuleJSON struct {
Path string // module path
Replace *ModuleJSON // replaced by this module
Main bool // is this the main module?
Indirect bool // is this module only an indirect dependency of main module?
Dir string // directory holding files for this module, if any
GoMod string // path to go.mod file for this module, if any
GoVersion string // go version used in module
var modFlagRegexp = regexp.MustCompile(`-mod[ =](\w+)`)
// VendorEnabled reports whether vendoring is enabled. It takes a *Runner to execute Go commands
// with the supplied context.Context and Invocation. The Invocation can contain pre-defined fields,
// of which only Verb and Args are modified to run the appropriate Go command.
// Inspired by setDefaultBuildMod in modload/init.go
func VendorEnabled(ctx context.Context, inv Invocation, r *Runner) (*ModuleJSON, bool, error) {
mainMod, go114, err := getMainModuleAnd114(ctx, inv, r)
if err != nil {
return nil, false, err
// We check the GOFLAGS to see if there is anything overridden or not.
inv.Verb = "env"
inv.Args = []string{"GOFLAGS"}
stdout, err := r.Run(ctx, inv)
if err != nil {
return nil, false, err
goflags := string(bytes.TrimSpace(stdout.Bytes()))
matches := modFlagRegexp.FindStringSubmatch(goflags)
var modFlag string
if len(matches) != 0 {
modFlag = matches[1]
if modFlag != "" {
// Don't override an explicit '-mod=' argument.
return mainMod, modFlag == "vendor", nil
if mainMod == nil || !go114 {
return mainMod, false, nil
// Check 1.14's automatic vendor mode.
if fi, err := os.Stat(filepath.Join(mainMod.Dir, "vendor")); err == nil && fi.IsDir() {
if mainMod.GoVersion != "" && semver.Compare("v"+mainMod.GoVersion, "v1.14") >= 0 {
// The Go version is at least 1.14, and a vendor directory exists.
// Set -mod=vendor by default.
return mainMod, true, nil
return mainMod, false, nil
// getMainModuleAnd114 gets the main module's information and whether the
// go command in use is 1.14+. This is the information needed to figure out
// if vendoring should be enabled.
func getMainModuleAnd114(ctx context.Context, inv Invocation, r *Runner) (*ModuleJSON, bool, error) {
const format = `{{.Path}}
{{range context.ReleaseTags}}{{if eq . "go1.14"}}{{.}}{{end}}{{end}}
inv.Verb = "list"
inv.Args = []string{"-m", "-f", format}
stdout, err := r.Run(ctx, inv)
if err != nil {
return nil, false, err
lines := strings.Split(stdout.String(), "\n")
if len(lines) < 5 {
return nil, false, fmt.Errorf("unexpected stdout: %q", stdout.String())
mod := &ModuleJSON{
Path: lines[0],
Dir: lines[1],
GoMod: lines[2],
GoVersion: lines[3],
Main: true,
return mod, lines[4] == "go1.14", nil