blob: 8e8fb9e6a1ff6a4d193b094de6eb6afec877d291 [file] [log] [blame]
// 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 modload
import (
"bytes"
"context"
"encoding/json"
"errors"
"fmt"
"go/build"
"internal/lazyregexp"
"io/ioutil"
"os"
"path"
"path/filepath"
"runtime/debug"
"strconv"
"strings"
"cmd/go/internal/base"
"cmd/go/internal/cfg"
"cmd/go/internal/load"
"cmd/go/internal/lockedfile"
"cmd/go/internal/modconv"
"cmd/go/internal/modfetch"
"cmd/go/internal/mvs"
"cmd/go/internal/search"
"golang.org/x/mod/modfile"
"golang.org/x/mod/module"
"golang.org/x/mod/semver"
)
var (
mustUseModules = false
initialized bool
modRoot string
Target module.Version
// targetPrefix is the path prefix for packages in Target, without a trailing
// slash. For most modules, targetPrefix is just Target.Path, but the
// standard-library module "std" has an empty prefix.
targetPrefix string
// targetInGorootSrc caches whether modRoot is within GOROOT/src.
// The "std" module is special within GOROOT/src, but not otherwise.
targetInGorootSrc bool
gopath string
CmdModInit bool // running 'go mod init'
CmdModModule string // module argument for 'go mod init'
allowMissingModuleImports bool
)
// ModFile returns the parsed go.mod file.
//
// Note that after calling ImportPaths or LoadBuildList,
// the require statements in the modfile.File are no longer
// the source of truth and will be ignored: edits made directly
// will be lost at the next call to WriteGoMod.
// To make permanent changes to the require statements
// in go.mod, edit it before calling ImportPaths or LoadBuildList.
func ModFile() *modfile.File {
Init()
if modFile == nil {
die()
}
return modFile
}
func BinDir() string {
Init()
return filepath.Join(gopath, "bin")
}
// Init determines whether module mode is enabled, locates the root of the
// current module (if any), sets environment variables for Git subprocesses, and
// configures the cfg, codehost, load, modfetch, and search packages for use
// with modules.
func Init() {
if initialized {
return
}
initialized = true
// Keep in sync with WillBeEnabled. We perform extra validation here, and
// there are lots of diagnostics and side effects, so we can't use
// WillBeEnabled directly.
env := cfg.Getenv("GO111MODULE")
switch env {
default:
base.Fatalf("go: unknown environment setting GO111MODULE=%s", env)
case "auto", "":
mustUseModules = false
case "on":
mustUseModules = true
case "off":
mustUseModules = false
return
}
// Disable any prompting for passwords by Git.
// Only has an effect for 2.3.0 or later, but avoiding
// the prompt in earlier versions is just too hard.
// If user has explicitly set GIT_TERMINAL_PROMPT=1, keep
// prompting.
// See golang.org/issue/9341 and golang.org/issue/12706.
if os.Getenv("GIT_TERMINAL_PROMPT") == "" {
os.Setenv("GIT_TERMINAL_PROMPT", "0")
}
// Disable any ssh connection pooling by Git.
// If a Git subprocess forks a child into the background to cache a new connection,
// that child keeps stdout/stderr open. After the Git subprocess exits,
// os /exec expects to be able to read from the stdout/stderr pipe
// until EOF to get all the data that the Git subprocess wrote before exiting.
// The EOF doesn't come until the child exits too, because the child
// is holding the write end of the pipe.
// This is unfortunate, but it has come up at least twice
// (see golang.org/issue/13453 and golang.org/issue/16104)
// and confuses users when it does.
// If the user has explicitly set GIT_SSH or GIT_SSH_COMMAND,
// assume they know what they are doing and don't step on it.
// But default to turning off ControlMaster.
if os.Getenv("GIT_SSH") == "" && os.Getenv("GIT_SSH_COMMAND") == "" {
os.Setenv("GIT_SSH_COMMAND", "ssh -o ControlMaster=no")
}
if CmdModInit {
// Running 'go mod init': go.mod will be created in current directory.
modRoot = base.Cwd
} else {
modRoot = findModuleRoot(base.Cwd)
if modRoot == "" {
if cfg.ModFile != "" {
base.Fatalf("go: cannot find main module, but -modfile was set.\n\t-modfile cannot be used to set the module root directory.")
}
if !mustUseModules {
// GO111MODULE is 'auto', and we can't find a module root.
// Stay in GOPATH mode.
return
}
} else if search.InDir(modRoot, os.TempDir()) == "." {
// If you create /tmp/go.mod for experimenting,
// then any tests that create work directories under /tmp
// will find it and get modules when they're not expecting them.
// It's a bit of a peculiar thing to disallow but quite mysterious
// when it happens. See golang.org/issue/26708.
modRoot = ""
fmt.Fprintf(os.Stderr, "go: warning: ignoring go.mod in system temp root %v\n", os.TempDir())
}
}
if cfg.ModFile != "" && !strings.HasSuffix(cfg.ModFile, ".mod") {
base.Fatalf("go: -modfile=%s: file does not have .mod extension", cfg.ModFile)
}
// We're in module mode. Install the hooks to make it work.
list := filepath.SplitList(cfg.BuildContext.GOPATH)
if len(list) == 0 || list[0] == "" {
base.Fatalf("missing $GOPATH")
}
gopath = list[0]
if _, err := os.Stat(filepath.Join(gopath, "go.mod")); err == nil {
base.Fatalf("$GOPATH/go.mod exists but should not")
}
cfg.ModulesEnabled = true
load.ModBinDir = BinDir
load.ModLookup = Lookup
load.ModPackageModuleInfo = PackageModuleInfo
load.ModImportPaths = ImportPaths
load.ModPackageBuildInfo = PackageBuildInfo
load.ModInfoProg = ModInfoProg
load.ModImportFromFiles = ImportFromFiles
load.ModDirImportPath = DirImportPath
if modRoot == "" {
// We're in module mode, but not inside a module.
//
// Commands like 'go build', 'go run', 'go list' have no go.mod file to
// read or write. They would need to find and download the latest versions
// of a potentially large number of modules with no way to save version
// information. We can succeed slowly (but not reproducibly), but that's
// not usually a good experience.
//
// Instead, we forbid resolving import paths to modules other than std and
// cmd. Users may still build packages specified with .go files on the
// command line, but they'll see an error if those files import anything
// outside std.
//
// This can be overridden by calling AllowMissingModuleImports.
// For example, 'go get' does this, since it is expected to resolve paths.
//
// See golang.org/issue/32027.
} else {
modfetch.GoSumFile = strings.TrimSuffix(ModFilePath(), ".mod") + ".sum"
search.SetModRoot(modRoot)
}
}
func init() {
load.ModInit = Init
}
// WillBeEnabled checks whether modules should be enabled but does not
// initialize modules by installing hooks. If Init has already been called,
// WillBeEnabled returns the same result as Enabled.
//
// This function is needed to break a cycle. The main package needs to know
// whether modules are enabled in order to install the module or GOPATH version
// of 'go get', but Init reads the -modfile flag in 'go get', so it shouldn't
// be called until the command is installed and flags are parsed. Instead of
// calling Init and Enabled, the main package can call this function.
func WillBeEnabled() bool {
if modRoot != "" || mustUseModules {
return true
}
if initialized {
return false
}
// Keep in sync with Init. Init does extra validation and prints warnings or
// exits, so it can't call this function directly.
env := cfg.Getenv("GO111MODULE")
switch env {
case "on":
return true
case "auto", "":
break
default:
return false
}
if CmdModInit {
// Running 'go mod init': go.mod will be created in current directory.
return true
}
if modRoot := findModuleRoot(base.Cwd); modRoot == "" {
// GO111MODULE is 'auto', and we can't find a module root.
// Stay in GOPATH mode.
return false
} else if search.InDir(modRoot, os.TempDir()) == "." {
// If you create /tmp/go.mod for experimenting,
// then any tests that create work directories under /tmp
// will find it and get modules when they're not expecting them.
// It's a bit of a peculiar thing to disallow but quite mysterious
// when it happens. See golang.org/issue/26708.
return false
}
return true
}
// Enabled reports whether modules are (or must be) enabled.
// If modules are enabled but there is no main module, Enabled returns true
// and then the first use of module information will call die
// (usually through MustModRoot).
func Enabled() bool {
Init()
return modRoot != "" || mustUseModules
}
// ModRoot returns the root of the main module.
// It calls base.Fatalf if there is no main module.
func ModRoot() string {
if !HasModRoot() {
die()
}
return modRoot
}
// HasModRoot reports whether a main module is present.
// HasModRoot may return false even if Enabled returns true: for example, 'get'
// does not require a main module.
func HasModRoot() bool {
Init()
return modRoot != ""
}
// ModFilePath returns the effective path of the go.mod file. Normally, this
// "go.mod" in the directory returned by ModRoot, but the -modfile flag may
// change its location. ModFilePath calls base.Fatalf if there is no main
// module, even if -modfile is set.
func ModFilePath() string {
if !HasModRoot() {
die()
}
if cfg.ModFile != "" {
return cfg.ModFile
}
return filepath.Join(modRoot, "go.mod")
}
// printStackInDie causes die to print a stack trace.
//
// It is enabled by the testgo tag, and helps to diagnose paths that
// unexpectedly require a main module.
var printStackInDie = false
func die() {
if printStackInDie {
debug.PrintStack()
}
if cfg.Getenv("GO111MODULE") == "off" {
base.Fatalf("go: modules disabled by GO111MODULE=off; see 'go help modules'")
}
if dir, name := findAltConfig(base.Cwd); dir != "" {
rel, err := filepath.Rel(base.Cwd, dir)
if err != nil {
rel = dir
}
cdCmd := ""
if rel != "." {
cdCmd = fmt.Sprintf("cd %s && ", rel)
}
base.Fatalf("go: cannot find main module, but found %s in %s\n\tto create a module there, run:\n\t%sgo mod init", name, dir, cdCmd)
}
base.Fatalf("go: cannot find main module; see 'go help modules'")
}
// InitMod sets Target and, if there is a main module, parses the initial build
// list from its go.mod file. If InitMod is called by 'go mod init', InitMod
// will populate go.mod in memory, possibly importing dependencies from a
// legacy configuration file. For other commands, InitMod may make other
// adjustments in memory, like adding a go directive. WriteGoMod should be
// called later to write changes out to disk.
//
// As a side-effect, InitMod sets a default for cfg.BuildMod if it does not
// already have an explicit value.
func InitMod(ctx context.Context) {
if len(buildList) > 0 {
return
}
Init()
if modRoot == "" {
Target = module.Version{Path: "command-line-arguments"}
targetPrefix = "command-line-arguments"
buildList = []module.Version{Target}
return
}
if CmdModInit {
// Running go mod init: do legacy module conversion
legacyModInit()
modFileToBuildList()
return
}
gomod := ModFilePath()
data, err := lockedfile.Read(gomod)
if err != nil {
base.Fatalf("go: %v", err)
}
var fixed bool
f, err := modfile.Parse(gomod, data, fixVersion(ctx, &fixed))
if err != nil {
// Errors returned by modfile.Parse begin with file:line.
base.Fatalf("go: errors parsing go.mod:\n%s\n", err)
}
modFile = f
index = indexModFile(data, f, fixed)
if f.Module == nil {
// No module declaration. Must add module path.
base.Fatalf("go: no module declaration in go.mod.\n\tRun 'go mod edit -module=example.com/mod' to specify the module path.")
}
if len(f.Syntax.Stmt) == 1 && f.Module != nil {
// Entire file is just a module statement.
// Populate require if possible.
legacyModInit()
}
if err := checkModulePathLax(f.Module.Mod.Path); err != nil {
base.Fatalf("go: %v", err)
}
setDefaultBuildMod()
modFileToBuildList()
if cfg.BuildMod == "vendor" {
readVendorList()
checkVendorConsistency()
}
}
// checkModulePathLax checks that the path meets some minimum requirements
// to avoid confusing users or the module cache. The requirements are weaker
// than those of module.CheckPath to allow room for weakening module path
// requirements in the future, but strong enough to help users avoid significant
// problems.
func checkModulePathLax(p string) error {
// TODO(matloob): Replace calls of this function in this CL with calls
// to module.CheckImportPath once it's been laxened, if it becomes laxened.
// See golang.org/issue/29101 for a discussion about whether to make CheckImportPath
// more lax or more strict.
errorf := func(format string, args ...interface{}) error {
return fmt.Errorf("invalid module path %q: %s", p, fmt.Sprintf(format, args...))
}
// Disallow shell characters " ' * < > ? ` | to avoid triggering bugs
// with file systems and subcommands. Disallow file path separators : and \
// because path separators other than / will confuse the module cache.
// See fileNameOK in golang.org/x/mod/module/module.go.
shellChars := "`" + `\"'*<>?|`
fsChars := `\:`
if i := strings.IndexAny(p, shellChars); i >= 0 {
return errorf("contains disallowed shell character %q", p[i])
}
if i := strings.IndexAny(p, fsChars); i >= 0 {
return errorf("contains disallowed path separator character %q", p[i])
}
// Ensure path.IsAbs and build.IsLocalImport are false, and that the path is
// invariant under path.Clean, also to avoid confusing the module cache.
if path.IsAbs(p) {
return errorf("is an absolute path")
}
if build.IsLocalImport(p) {
return errorf("is a local import path")
}
if path.Clean(p) != p {
return errorf("is not clean")
}
return nil
}
// fixVersion returns a modfile.VersionFixer implemented using the Query function.
//
// It resolves commit hashes and branch names to versions,
// canonicalizes versions that appeared in early vgo drafts,
// and does nothing for versions that already appear to be canonical.
//
// The VersionFixer sets 'fixed' if it ever returns a non-canonical version.
func fixVersion(ctx context.Context, fixed *bool) modfile.VersionFixer {
return func(path, vers string) (resolved string, err error) {
defer func() {
if err == nil && resolved != vers {
*fixed = true
}
}()
// Special case: remove the old -gopkgin- hack.
if strings.HasPrefix(path, "gopkg.in/") && strings.Contains(vers, "-gopkgin-") {
vers = vers[strings.Index(vers, "-gopkgin-")+len("-gopkgin-"):]
}
// fixVersion is called speculatively on every
// module, version pair from every go.mod file.
// Avoid the query if it looks OK.
_, pathMajor, ok := module.SplitPathVersion(path)
if !ok {
return "", &module.ModuleError{
Path: path,
Err: &module.InvalidVersionError{
Version: vers,
Err: fmt.Errorf("malformed module path %q", path),
},
}
}
if vers != "" && module.CanonicalVersion(vers) == vers {
if err := module.CheckPathMajor(vers, pathMajor); err == nil {
return vers, nil
}
}
info, err := Query(ctx, path, vers, "", nil)
if err != nil {
return "", err
}
return info.Version, nil
}
}
// AllowMissingModuleImports allows import paths to be resolved to modules
// when there is no module root. Normally, this is forbidden because it's slow
// and there's no way to make the result reproducible, but some commands
// like 'go get' are expected to do this.
func AllowMissingModuleImports() {
allowMissingModuleImports = true
}
// modFileToBuildList initializes buildList from the modFile.
func modFileToBuildList() {
Target = modFile.Module.Mod
targetPrefix = Target.Path
if rel := search.InDir(base.Cwd, cfg.GOROOTsrc); rel != "" {
targetInGorootSrc = true
if Target.Path == "std" {
targetPrefix = ""
}
}
list := []module.Version{Target}
for _, r := range modFile.Require {
if index != nil && index.exclude[r.Mod] {
if cfg.BuildMod == "mod" {
fmt.Fprintf(os.Stderr, "go: dropping requirement on excluded version %s %s\n", r.Mod.Path, r.Mod.Version)
} else {
fmt.Fprintf(os.Stderr, "go: ignoring requirement on excluded version %s %s\n", r.Mod.Path, r.Mod.Version)
}
} else {
list = append(list, r.Mod)
}
}
buildList = list
}
// setDefaultBuildMod sets a default value for cfg.BuildMod
// if it is currently empty.
func setDefaultBuildMod() {
if cfg.BuildMod != "" {
// Don't override an explicit '-mod=' argument.
return
}
cfg.BuildMod = "mod"
if cfg.CmdName == "get" || strings.HasPrefix(cfg.CmdName, "mod ") {
// Don't set -mod implicitly for commands whose purpose is to
// manipulate the build list.
return
}
if modRoot == "" {
return
}
if fi, err := os.Stat(filepath.Join(modRoot, "vendor")); err == nil && fi.IsDir() {
modGo := "unspecified"
if index.goVersionV != "" {
if semver.Compare(index.goVersionV, "v1.14") >= 0 {
// The Go version is at least 1.14, and a vendor directory exists.
// Set -mod=vendor by default.
cfg.BuildMod = "vendor"
cfg.BuildModReason = "Go version in go.mod is at least 1.14 and vendor directory exists."
return
} else {
modGo = index.goVersionV[1:]
}
}
// Since a vendor directory exists, we have a non-trivial reason for
// choosing -mod=mod, although it probably won't be used for anything.
// Record the reason anyway for consistency.
// It may be overridden if we switch to mod=readonly below.
cfg.BuildModReason = fmt.Sprintf("Go version in go.mod is %s.", modGo)
}
p := ModFilePath()
if fi, err := os.Stat(p); err == nil && !hasWritePerm(p, fi) {
cfg.BuildMod = "readonly"
cfg.BuildModReason = "go.mod file is read-only."
}
}
func legacyModInit() {
if modFile == nil {
path, err := findModulePath(modRoot)
if err != nil {
base.Fatalf("go: %v", err)
}
fmt.Fprintf(os.Stderr, "go: creating new go.mod: module %s\n", path)
modFile = new(modfile.File)
modFile.AddModuleStmt(path)
addGoStmt() // Add the go directive before converted module requirements.
}
for _, name := range altConfigs {
cfg := filepath.Join(modRoot, name)
data, err := ioutil.ReadFile(cfg)
if err == nil {
convert := modconv.Converters[name]
if convert == nil {
return
}
fmt.Fprintf(os.Stderr, "go: copying requirements from %s\n", base.ShortPath(cfg))
cfg = filepath.ToSlash(cfg)
if err := modconv.ConvertLegacyConfig(modFile, cfg, data); err != nil {
base.Fatalf("go: %v", err)
}
if len(modFile.Syntax.Stmt) == 1 {
// Add comment to avoid re-converting every time it runs.
modFile.AddComment("// go: no requirements found in " + name)
}
return
}
}
}
// addGoStmt adds a go directive to the go.mod file if it does not already include one.
// The 'go' version added, if any, is the latest version supported by this toolchain.
func addGoStmt() {
if modFile.Go != nil && modFile.Go.Version != "" {
return
}
tags := build.Default.ReleaseTags
version := tags[len(tags)-1]
if !strings.HasPrefix(version, "go") || !modfile.GoVersionRE.MatchString(version[2:]) {
base.Fatalf("go: unrecognized default version %q", version)
}
if err := modFile.AddGoStmt(version[2:]); err != nil {
base.Fatalf("go: internal error: %v", err)
}
}
var altConfigs = []string{
"Gopkg.lock",
"GLOCKFILE",
"Godeps/Godeps.json",
"dependencies.tsv",
"glide.lock",
"vendor.conf",
"vendor.yml",
"vendor/manifest",
"vendor/vendor.json",
".git/config",
}
func findModuleRoot(dir string) (root string) {
if dir == "" {
panic("dir not set")
}
dir = filepath.Clean(dir)
// Look for enclosing go.mod.
for {
if fi, err := os.Stat(filepath.Join(dir, "go.mod")); err == nil && !fi.IsDir() {
return dir
}
d := filepath.Dir(dir)
if d == dir {
break
}
dir = d
}
return ""
}
func findAltConfig(dir string) (root, name string) {
if dir == "" {
panic("dir not set")
}
dir = filepath.Clean(dir)
if rel := search.InDir(dir, cfg.BuildContext.GOROOT); rel != "" {
// Don't suggest creating a module from $GOROOT/.git/config
// or a config file found in any parent of $GOROOT (see #34191).
return "", ""
}
for {
for _, name := range altConfigs {
if fi, err := os.Stat(filepath.Join(dir, name)); err == nil && !fi.IsDir() {
return dir, name
}
}
d := filepath.Dir(dir)
if d == dir {
break
}
dir = d
}
return "", ""
}
func findModulePath(dir string) (string, error) {
if CmdModModule != "" {
// Running go mod init x/y/z; return x/y/z.
if err := module.CheckImportPath(CmdModModule); err != nil {
return "", err
}
return CmdModModule, nil
}
// TODO(bcmills): once we have located a plausible module path, we should
// query version control (if available) to verify that it matches the major
// version of the most recent tag.
// See https://golang.org/issue/29433, https://golang.org/issue/27009, and
// https://golang.org/issue/31549.
// Cast about for import comments,
// first in top-level directory, then in subdirectories.
list, _ := ioutil.ReadDir(dir)
for _, info := range list {
if info.Mode().IsRegular() && strings.HasSuffix(info.Name(), ".go") {
if com := findImportComment(filepath.Join(dir, info.Name())); com != "" {
return com, nil
}
}
}
for _, info1 := range list {
if info1.IsDir() {
files, _ := ioutil.ReadDir(filepath.Join(dir, info1.Name()))
for _, info2 := range files {
if info2.Mode().IsRegular() && strings.HasSuffix(info2.Name(), ".go") {
if com := findImportComment(filepath.Join(dir, info1.Name(), info2.Name())); com != "" {
return path.Dir(com), nil
}
}
}
}
}
// Look for Godeps.json declaring import path.
data, _ := ioutil.ReadFile(filepath.Join(dir, "Godeps/Godeps.json"))
var cfg1 struct{ ImportPath string }
json.Unmarshal(data, &cfg1)
if cfg1.ImportPath != "" {
return cfg1.ImportPath, nil
}
// Look for vendor.json declaring import path.
data, _ = ioutil.ReadFile(filepath.Join(dir, "vendor/vendor.json"))
var cfg2 struct{ RootPath string }
json.Unmarshal(data, &cfg2)
if cfg2.RootPath != "" {
return cfg2.RootPath, nil
}
// Look for path in GOPATH.
var badPathErr error
for _, gpdir := range filepath.SplitList(cfg.BuildContext.GOPATH) {
if gpdir == "" {
continue
}
if rel := search.InDir(dir, filepath.Join(gpdir, "src")); rel != "" && rel != "." {
path := filepath.ToSlash(rel)
// TODO(matloob): replace this with module.CheckImportPath
// once it's been laxened.
// Only checkModulePathLax here. There are some unpublishable
// module names that are compatible with checkModulePathLax
// but they already work in GOPATH so don't break users
// trying to do a build with modules. gorelease will alert users
// publishing their modules to fix their paths.
if err := checkModulePathLax(path); err != nil {
badPathErr = err
break
}
return path, nil
}
}
reason := "outside GOPATH, module path must be specified"
if badPathErr != nil {
// return a different error message if the module was in GOPATH, but
// the module path determined above would be an invalid path.
reason = fmt.Sprintf("bad module path inferred from directory in GOPATH: %v", badPathErr)
}
msg := `cannot determine module path for source directory %s (%s)
Example usage:
'go mod init example.com/m' to initialize a v0 or v1 module
'go mod init example.com/m/v2' to initialize a v2 module
Run 'go help mod init' for more information.
`
return "", fmt.Errorf(msg, dir, reason)
}
var (
importCommentRE = lazyregexp.New(`(?m)^package[ \t]+[^ \t\r\n/]+[ \t]+//[ \t]+import[ \t]+(\"[^"]+\")[ \t]*\r?\n`)
)
func findImportComment(file string) string {
data, err := ioutil.ReadFile(file)
if err != nil {
return ""
}
m := importCommentRE.FindSubmatch(data)
if m == nil {
return ""
}
path, err := strconv.Unquote(string(m[1]))
if err != nil {
return ""
}
return path
}
var allowWriteGoMod = true
// DisallowWriteGoMod causes future calls to WriteGoMod to do nothing at all.
func DisallowWriteGoMod() {
allowWriteGoMod = false
}
// AllowWriteGoMod undoes the effect of DisallowWriteGoMod:
// future calls to WriteGoMod will update go.mod if needed.
// Note that any past calls have been discarded, so typically
// a call to AlowWriteGoMod should be followed by a call to WriteGoMod.
func AllowWriteGoMod() {
allowWriteGoMod = true
}
// MinReqs returns a Reqs with minimal additional dependencies of Target,
// as will be written to go.mod.
func MinReqs() mvs.Reqs {
var retain []string
for _, m := range buildList[1:] {
_, explicit := index.require[m]
if explicit || loaded.direct[m.Path] {
retain = append(retain, m.Path)
}
}
min, err := mvs.Req(Target, retain, Reqs())
if err != nil {
base.Fatalf("go: %v", err)
}
return &mvsReqs{buildList: append([]module.Version{Target}, min...)}
}
// WriteGoMod writes the current build list back to go.mod.
func WriteGoMod() {
// If we're using -mod=vendor we basically ignored
// go.mod, so definitely don't try to write back our
// incomplete view of the world.
if !allowWriteGoMod || cfg.BuildMod == "vendor" {
return
}
// If we aren't in a module, we don't have anywhere to write a go.mod file.
if modRoot == "" {
return
}
if cfg.BuildMod != "readonly" {
addGoStmt()
}
if loaded != nil {
reqs := MinReqs()
min, err := reqs.Required(Target)
if err != nil {
base.Fatalf("go: %v", err)
}
var list []*modfile.Require
for _, m := range min {
list = append(list, &modfile.Require{
Mod: m,
Indirect: !loaded.direct[m.Path],
})
}
modFile.SetRequire(list)
}
modFile.Cleanup()
dirty := index.modFileIsDirty(modFile)
if dirty && cfg.BuildMod == "readonly" {
// If we're about to fail due to -mod=readonly,
// prefer to report a dirty go.mod over a dirty go.sum
if cfg.BuildModReason != "" {
base.Fatalf("go: updates to go.mod needed, disabled by -mod=readonly\n\t(%s)", cfg.BuildModReason)
} else {
base.Fatalf("go: updates to go.mod needed, disabled by -mod=readonly")
}
}
if !dirty && cfg.CmdName != "mod tidy" {
// The go.mod file has the same semantic content that it had before
// (but not necessarily the same exact bytes).
// Don't write go.mod, but write go.sum in case we added or trimmed sums.
modfetch.WriteGoSum(keepSums(true))
return
}
new, err := modFile.Format()
if err != nil {
base.Fatalf("go: %v", err)
}
defer func() {
// At this point we have determined to make the go.mod file on disk equal to new.
index = indexModFile(new, modFile, false)
// Update go.sum after releasing the side lock and refreshing the index.
modfetch.WriteGoSum(keepSums(true))
}()
// 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()
}
errNoChange := errors.New("no update needed")
err = lockedfile.Transform(ModFilePath(), func(old []byte) ([]byte, error) {
if bytes.Equal(old, new) {
// The go.mod file is already equal to new, possibly as the result of some
// other process.
return nil, errNoChange
}
if index != nil && !bytes.Equal(old, index.data) {
// The contents of the go.mod file have changed. In theory we could add all
// of the new modules to the build list, recompute, and check whether any
// module in *our* build list got bumped to a different version, but that's
// a lot of work for marginal benefit. Instead, fail the command: if users
// want to run concurrent commands, they need to start with a complete,
// consistent module definition.
return nil, fmt.Errorf("existing contents have changed since last read")
}
return new, nil
})
if err != nil && err != errNoChange {
base.Fatalf("go: updating go.mod: %v", err)
}
}
// keepSums returns a set of module sums to preserve in go.sum. The set
// includes entries for all modules used to load packages (according to
// the last load function like ImportPaths, LoadALL, etc.). It also contains
// entries for go.mod files needed for MVS (the version of these entries
// ends with "/go.mod").
//
// If addDirect is true, the set also includes sums for modules directly
// required by go.mod, as represented by the index, with replacements applied.
func keepSums(addDirect bool) map[module.Version]bool {
// Walk the module graph and keep sums needed by MVS.
modkey := func(m module.Version) module.Version {
return module.Version{Path: m.Path, Version: m.Version + "/go.mod"}
}
keep := make(map[module.Version]bool)
replaced := make(map[module.Version]bool)
reqs := Reqs()
var walk func(module.Version)
walk = func(m module.Version) {
// If we build using a replacement module, keep the sum for the replacement,
// since that's the code we'll actually use during a build.
r := Replacement(m)
if r.Path == "" {
keep[modkey(m)] = true
} else {
replaced[m] = true
keep[modkey(r)] = true
}
list, _ := reqs.Required(m)
for _, r := range list {
if !keep[modkey(r)] && !replaced[r] {
walk(r)
}
}
}
walk(Target)
// Add entries for modules that provided packages loaded with ImportPaths,
// LoadALL, or similar functions.
if loaded != nil {
for _, pkg := range loaded.pkgs {
m := pkg.mod
if r := Replacement(m); r.Path != "" {
keep[r] = true
} else {
keep[m] = true
}
}
}
// Add entries for modules directly required by go.mod.
if addDirect {
for m := range index.require {
var kept module.Version
if r := Replacement(m); r.Path != "" {
kept = r
} else {
kept = m
}
keep[kept] = true
keep[module.Version{Path: kept.Path, Version: kept.Version + "/go.mod"}] = true
}
}
return keep
}
func TrimGoSum() {
// Don't retain sums for direct requirements in go.mod. When TrimGoSum is
// called, go.mod has not been updated, and it may contain requirements on
// modules deleted from the build list.
addDirect := false
modfetch.TrimGoSum(keepSums(addDirect))
}