Rename scripts to build and add revive command as a new build tool command (#10942)

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

vendor/golang.org/x/tools/internal/fastwalk/fastwalk.go

@@ -14,14 +14,14 @@ import (
 	"sync"
 )
 
-// TraverseLink is used as a return value from WalkFuncs to indicate that the
+// ErrTraverseLink is used as a return value from WalkFuncs to indicate that the
 // symlink named in the call may be traversed.
-var TraverseLink = errors.New("fastwalk: traverse symlink, assuming target is a directory")
+var ErrTraverseLink = errors.New("fastwalk: traverse symlink, assuming target is a directory")
 
-// SkipFiles is a used as a return value from WalkFuncs to indicate that the
+// ErrSkipFiles is a used as a return value from WalkFuncs to indicate that the
 // callback should not be called for any other files in the current directory.
 // Child directories will still be traversed.
-var SkipFiles = errors.New("fastwalk: skip remaining files in directory")
+var ErrSkipFiles = errors.New("fastwalk: skip remaining files in directory")
 
 // Walk is a faster implementation of filepath.Walk.
 //
@@ -167,7 +167,7 @@ func (w *walker) onDirEnt(dirName, baseName string, typ os.FileMode) error {
 
 	err := w.fn(joined, typ)
 	if typ == os.ModeSymlink {
-		if err == TraverseLink {
+		if err == ErrTraverseLink {
 			// Set callbackDone so we don't call it twice for both the
 			// symlink-as-symlink and the symlink-as-directory later:
 			w.enqueue(walkItem{dir: joined, callbackDone: true})

vendor/golang.org/x/tools/internal/fastwalk/fastwalk_portable.go

@@ -26,7 +26,7 @@ func readDir(dirName string, fn func(dirName, entName string, typ os.FileMode) e
 			continue
 		}
 		if err := fn(dirName, fi.Name(), fi.Mode()&os.ModeType); err != nil {
-			if err == SkipFiles {
+			if err == ErrSkipFiles {
 				skipFiles = true
 				continue
 			}

vendor/golang.org/x/tools/internal/fastwalk/fastwalk_unix.go

@@ -66,7 +66,7 @@ func readDir(dirName string, fn func(dirName, entName string, typ os.FileMode) e
 			continue
 		}
 		if err := fn(dirName, name, typ); err != nil {
-			if err == SkipFiles {
+			if err == ErrSkipFiles {
 				skipFiles = true
 				continue
 			}

vendor/golang.org/x/tools/internal/gocommand/invoke.go

@@ -0,0 +1,121 @@
+// Package gocommand is a helper for calling the go command.
+package gocommand
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+	"time"
+)
+
+// An Invocation represents a call to the go command.
+type Invocation struct {
+	Verb       string
+	Args       []string
+	BuildFlags []string
+	Env        []string
+	WorkingDir string
+	Logf       func(format string, args ...interface{})
+}
+
+// Run runs the invocation, returning its stdout and an error suitable for
+// human consumption, including stderr.
+func (i *Invocation) Run(ctx context.Context) (*bytes.Buffer, error) {
+	stdout, _, friendly, _ := i.RunRaw(ctx)
+	return stdout, friendly
+}
+
+// RunRaw is like Run, but also returns the raw stderr and error for callers
+// that want to do low-level error handling/recovery.
+func (i *Invocation) RunRaw(ctx context.Context) (stdout *bytes.Buffer, stderr *bytes.Buffer, friendlyError error, rawError error) {
+	log := i.Logf
+	if log == nil {
+		log = func(string, ...interface{}) {}
+	}
+
+	goArgs := []string{i.Verb}
+	switch i.Verb {
+	case "mod":
+		// mod needs the sub-verb before build flags.
+		goArgs = append(goArgs, i.Args[0])
+		goArgs = append(goArgs, i.BuildFlags...)
+		goArgs = append(goArgs, i.Args[1:]...)
+	case "env":
+		// env doesn't take build flags.
+		goArgs = append(goArgs, i.Args...)
+	default:
+		goArgs = append(goArgs, i.BuildFlags...)
+		goArgs = append(goArgs, i.Args...)
+	}
+	cmd := exec.Command("go", goArgs...)
+	stdout = &bytes.Buffer{}
+	stderr = &bytes.Buffer{}
+	cmd.Stdout = stdout
+	cmd.Stderr = stderr
+	// On darwin the cwd gets resolved to the real path, which breaks anything that
+	// expects the working directory to keep the original path, including the
+	// go command when dealing with modules.
+	// The Go stdlib has a special feature where if the cwd and the PWD are the
+	// same node then it trusts the PWD, so by setting it in the env for the child
+	// process we fix up all the paths returned by the go command.
+	cmd.Env = append(append([]string{}, i.Env...), "PWD="+i.WorkingDir)
+	cmd.Dir = i.WorkingDir
+
+	defer func(start time.Time) { log("%s for %v", time.Since(start), cmdDebugStr(cmd)) }(time.Now())
+
+	rawError = runCmdContext(ctx, cmd)
+	friendlyError = rawError
+	if rawError != nil {
+		// Check for 'go' executable not being found.
+		if ee, ok := rawError.(*exec.Error); ok && ee.Err == exec.ErrNotFound {
+			friendlyError = fmt.Errorf("go command required, not found: %v", ee)
+		}
+		if ctx.Err() != nil {
+			friendlyError = ctx.Err()
+		}
+		friendlyError = fmt.Errorf("err: %v: stderr: %s", rawError, stderr)
+	}
+	return
+}
+
+// runCmdContext is like exec.CommandContext except it sends os.Interrupt
+// before os.Kill.
+func runCmdContext(ctx context.Context, cmd *exec.Cmd) error {
+	if err := cmd.Start(); err != nil {
+		return err
+	}
+	resChan := make(chan error, 1)
+	go func() {
+		resChan <- cmd.Wait()
+	}()
+
+	select {
+	case err := <-resChan:
+		return err
+	case <-ctx.Done():
+	}
+	// Cancelled. Interrupt and see if it ends voluntarily.
+	cmd.Process.Signal(os.Interrupt)
+	select {
+	case err := <-resChan:
+		return err
+	case <-time.After(time.Second):
+	}
+	// Didn't shut down in response to interrupt. Kill it hard.
+	cmd.Process.Kill()
+	return <-resChan
+}
+
+func cmdDebugStr(cmd *exec.Cmd) string {
+	env := make(map[string]string)
+	for _, kv := range cmd.Env {
+		split := strings.Split(kv, "=")
+		k, v := split[0], split[1]
+		env[k] = v
+	}
+
+	return fmt.Sprintf("GOROOT=%v GOPATH=%v GO111MODULE=%v GOPROXY=%v PWD=%v go %v", env["GOROOT"], env["GOPATH"], env["GO111MODULE"], env["GOPROXY"], env["PWD"], cmd.Args)
+}

vendor/golang.org/x/tools/internal/gopathwalk/walk.go

@@ -77,6 +77,7 @@ func WalkSkip(roots []Root, add func(root Root, dir string), skip func(root Root
 	}
 }
 
+// walkDir creates a walker and starts fastwalk with this walker.
 func walkDir(root Root, add func(Root, string), skip func(root Root, dir string) bool, opts Options) {
 	if _, err := os.Stat(root.Path); os.IsNotExist(err) {
 		if opts.Debug {
@@ -114,7 +115,7 @@ type walker struct {
 	ignoredDirs []os.FileInfo // The ignored directories, loaded from .goimportsignore files.
 }
 
-// init initializes the walker based on its Options.
+// init initializes the walker based on its Options
 func (w *walker) init() {
 	var ignoredPaths []string
 	if w.root.Type == RootModuleCache {
@@ -167,6 +168,7 @@ func (w *walker) getIgnoredDirs(path string) []string {
 	return ignoredDirs
 }
 
+// shouldSkipDir reports whether the file should be skipped or not.
 func (w *walker) shouldSkipDir(fi os.FileInfo, dir string) bool {
 	for _, ignoredDir := range w.ignoredDirs {
 		if os.SameFile(fi, ignoredDir) {
@@ -180,20 +182,21 @@ func (w *walker) shouldSkipDir(fi os.FileInfo, dir string) bool {
 	return false
 }
 
+// walk walks through the given path.
 func (w *walker) walk(path string, typ os.FileMode) error {
 	dir := filepath.Dir(path)
 	if typ.IsRegular() {
 		if dir == w.root.Path && (w.root.Type == RootGOROOT || w.root.Type == RootGOPATH) {
 			// Doesn't make sense to have regular files
 			// directly in your $GOPATH/src or $GOROOT/src.
-			return fastwalk.SkipFiles
+			return fastwalk.ErrSkipFiles
 		}
 		if !strings.HasSuffix(path, ".go") {
 			return nil
 		}
 
 		w.add(w.root, dir)
-		return fastwalk.SkipFiles
+		return fastwalk.ErrSkipFiles
 	}
 	if typ == os.ModeDir {
 		base := filepath.Base(path)
@@ -221,7 +224,7 @@ func (w *walker) walk(path string, typ os.FileMode) error {
 			return nil
 		}
 		if w.shouldTraverse(dir, fi) {
-			return fastwalk.TraverseLink
+			return fastwalk.ErrTraverseLink
 		}
 	}
 	return nil

vendor/golang.org/x/tools/internal/imports/fix.go

@@ -14,7 +14,6 @@ import (
 	"go/token"
 	"io/ioutil"
 	"os"
-	"os/exec"
 	"path"
 	"path/filepath"
 	"reflect"
@@ -22,12 +21,11 @@ import (
 	"strconv"
 	"strings"
 	"sync"
-	"time"
 	"unicode"
 	"unicode/utf8"
 
 	"golang.org/x/tools/go/ast/astutil"
-	"golang.org/x/tools/go/packages"
+	"golang.org/x/tools/internal/gocommand"
 	"golang.org/x/tools/internal/gopathwalk"
 )
 
@@ -82,7 +80,8 @@ type ImportFix struct {
 	// IdentName is the identifier that this fix will add or remove.
 	IdentName string
 	// FixType is the type of fix this is (AddImport, DeleteImport, SetImportName).
-	FixType ImportFixType
+	FixType   ImportFixType
+	Relevance int // see pkg
 }
 
 // An ImportInfo represents a single import statement.
@@ -537,7 +536,7 @@ func getFixes(fset *token.FileSet, f *ast.File, filename string, env *ProcessEnv
 	// derive package names from import paths, see if the file is already
 	// complete. We can't add any imports yet, because we don't know
 	// if missing references are actually package vars.
-	p := &pass{fset: fset, f: f, srcDir: srcDir}
+	p := &pass{fset: fset, f: f, srcDir: srcDir, env: env}
 	if fixes, done := p.load(); done {
 		return fixes, nil
 	}
@@ -559,8 +558,7 @@ func getFixes(fset *token.FileSet, f *ast.File, filename string, env *ProcessEnv
 	}
 
 	// Third pass: get real package names where we had previously used
-	// the naive algorithm. This is the first step that will use the
-	// environment, so we provide it here for the first time.
+	// the naive algorithm.
 	p = &pass{fset: fset, f: f, srcDir: srcDir, env: env}
 	p.loadRealPackageNames = true
 	p.otherFiles = otherFiles
@@ -585,62 +583,86 @@ func getFixes(fset *token.FileSet, f *ast.File, filename string, env *ProcessEnv
 	return fixes, nil
 }
 
-// getCandidatePkgs returns the list of pkgs that are accessible from filename,
-// optionall filtered to only packages named pkgName.
-func getCandidatePkgs(pkgName, filename string, env *ProcessEnv) ([]*pkg, error) {
-	// TODO(heschi): filter out current package. (Don't forget x_test can import x.)
+// Highest relevance, used for the standard library. Chosen arbitrarily to
+// match pre-existing gopls code.
+const MaxRelevance = 7
 
-	var result []*pkg
+// getCandidatePkgs works with the passed callback to find all acceptable packages.
+// It deduplicates by import path, and uses a cached stdlib rather than reading
+// from disk.
+func getCandidatePkgs(ctx context.Context, wrappedCallback *scanCallback, filename, filePkg string, env *ProcessEnv) error {
+	notSelf := func(p *pkg) bool {
+		return p.packageName != filePkg || p.dir != filepath.Dir(filename)
+	}
 	// Start off with the standard library.
-	for importPath := range stdlib {
-		if pkgName != "" && path.Base(importPath) != pkgName {
-			continue
-		}
-		result = append(result, &pkg{
+	for importPath, exports := range stdlib {
+		p := &pkg{
 			dir:             filepath.Join(env.GOROOT, "src", importPath),
 			importPathShort: importPath,
 			packageName:     path.Base(importPath),
-			relevance:       0,
-		})
-	}
-
-	// Exclude goroot results -- getting them is relatively expensive, not cached,
-	// and generally redundant with the in-memory version.
-	exclude := []gopathwalk.RootType{gopathwalk.RootGOROOT}
-	// Only the go/packages resolver uses the first argument, and nobody uses that resolver.
-	scannedPkgs, err := env.GetResolver().scan(nil, true, exclude)
-	if err != nil {
-		return nil, err
+			relevance:       MaxRelevance,
+		}
+		if notSelf(p) && wrappedCallback.packageNameLoaded(p) {
+			wrappedCallback.exportsLoaded(p, exports)
+		}
 	}
 
+	var mu sync.Mutex
 	dupCheck := map[string]struct{}{}
-	for _, pkg := range scannedPkgs {
-		if pkgName != "" && pkg.packageName != pkgName {
-			continue
-		}
-		if !canUse(filename, pkg.dir) {
-			continue
-		}
-		if _, ok := dupCheck[pkg.importPathShort]; ok {
-			continue
-		}
-		dupCheck[pkg.importPathShort] = struct{}{}
-		result = append(result, pkg)
+
+	scanFilter := &scanCallback{
+		rootFound: func(root gopathwalk.Root) bool {
+			// Exclude goroot results -- getting them is relatively expensive, not cached,
+			// and generally redundant with the in-memory version.
+			return root.Type != gopathwalk.RootGOROOT && wrappedCallback.rootFound(root)
+		},
+		dirFound: wrappedCallback.dirFound,
+		packageNameLoaded: func(pkg *pkg) bool {
+			mu.Lock()
+			defer mu.Unlock()
+			if _, ok := dupCheck[pkg.importPathShort]; ok {
+				return false
+			}
+			dupCheck[pkg.importPathShort] = struct{}{}
+			return notSelf(pkg) && wrappedCallback.packageNameLoaded(pkg)
+		},
+		exportsLoaded: func(pkg *pkg, exports []string) {
+			// If we're an x_test, load the package under test's test variant.
+			if strings.HasSuffix(filePkg, "_test") && pkg.dir == filepath.Dir(filename) {
+				var err error
+				_, exports, err = loadExportsFromFiles(ctx, env, pkg.dir, true)
+				if err != nil {
+					return
+				}
+			}
+			wrappedCallback.exportsLoaded(pkg, exports)
+		},
 	}
+	return env.GetResolver().scan(ctx, scanFilter)
+}
 
-	// Sort first by relevance, then by package name, with import path as a tiebreaker.
-	sort.Slice(result, func(i, j int) bool {
-		pi, pj := result[i], result[j]
-		if pi.relevance != pj.relevance {
-			return pi.relevance < pj.relevance
-		}
-		if pi.packageName != pj.packageName {
-			return pi.packageName < pj.packageName
-		}
-		return pi.importPathShort < pj.importPathShort
-	})
+func ScoreImportPaths(ctx context.Context, env *ProcessEnv, paths []string) map[string]int {
+	result := make(map[string]int)
+	for _, path := range paths {
+		result[path] = env.GetResolver().scoreImportPath(ctx, path)
+	}
+	return result
+}
 
-	return result, nil
+func PrimeCache(ctx context.Context, env *ProcessEnv) error {
+	// Fully scan the disk for directories, but don't actually read any Go files.
+	callback := &scanCallback{
+		rootFound: func(gopathwalk.Root) bool {
+			return true
+		},
+		dirFound: func(pkg *pkg) bool {
+			return false
+		},
+		packageNameLoaded: func(pkg *pkg) bool {
+			return false
+		},
+	}
+	return getCandidatePkgs(ctx, callback, "", "", env)
 }
 
 func candidateImportName(pkg *pkg) string {
@@ -651,23 +673,37 @@ func candidateImportName(pkg *pkg) string {
 }
 
 // getAllCandidates gets all of the candidates to be imported, regardless of if they are needed.
-func getAllCandidates(filename string, env *ProcessEnv) ([]ImportFix, error) {
-	pkgs, err := getCandidatePkgs("", filename, env)
-	if err != nil {
-		return nil, err
+func getAllCandidates(ctx context.Context, wrapped func(ImportFix), searchPrefix, filename, filePkg string, env *ProcessEnv) error {
+	callback := &scanCallback{
+		rootFound: func(gopathwalk.Root) bool {
+			return true
+		},
+		dirFound: func(pkg *pkg) bool {
+			if !canUse(filename, pkg.dir) {
+				return false
+			}
+			// Try the assumed package name first, then a simpler path match
+			// in case of packages named vN, which are not uncommon.
+			return strings.HasPrefix(ImportPathToAssumedName(pkg.importPathShort), searchPrefix) ||
+				strings.HasPrefix(path.Base(pkg.importPathShort), searchPrefix)
+		},
+		packageNameLoaded: func(pkg *pkg) bool {
+			if !strings.HasPrefix(pkg.packageName, searchPrefix) {
+				return false
+			}
+			wrapped(ImportFix{
+				StmtInfo: ImportInfo{
+					ImportPath: pkg.importPathShort,
+					Name:       candidateImportName(pkg),
+				},
+				IdentName: pkg.packageName,
+				FixType:   AddImport,
+				Relevance: pkg.relevance,
+			})
+			return false
+		},
 	}
-	result := make([]ImportFix, 0, len(pkgs))
-	for _, pkg := range pkgs {
-		result = append(result, ImportFix{
-			StmtInfo: ImportInfo{
-				ImportPath: pkg.importPathShort,
-				Name:       candidateImportName(pkg),
-			},
-			IdentName: pkg.packageName,
-			FixType:   AddImport,
-		})
-	}
-	return result, nil
+	return getCandidatePkgs(ctx, callback, filename, filePkg, env)
 }
 
 // A PackageExport is a package and its exports.
@@ -676,42 +712,34 @@ type PackageExport struct {
 	Exports []string
 }
 
-func getPackageExports(completePackage, filename string, env *ProcessEnv) ([]PackageExport, error) {
-	pkgs, err := getCandidatePkgs(completePackage, filename, env)
-	if err != nil {
-		return nil, err
+func getPackageExports(ctx context.Context, wrapped func(PackageExport), searchPkg, filename, filePkg string, env *ProcessEnv) error {
+	callback := &scanCallback{
+		rootFound: func(gopathwalk.Root) bool {
+			return true
+		},
+		dirFound: func(pkg *pkg) bool {
+			return pkgIsCandidate(filename, references{searchPkg: nil}, pkg)
+		},
+		packageNameLoaded: func(pkg *pkg) bool {
+			return pkg.packageName == searchPkg
+		},
+		exportsLoaded: func(pkg *pkg, exports []string) {
+			sort.Strings(exports)
+			wrapped(PackageExport{
+				Fix: &ImportFix{
+					StmtInfo: ImportInfo{
+						ImportPath: pkg.importPathShort,
+						Name:       candidateImportName(pkg),
+					},
+					IdentName: pkg.packageName,
+					FixType:   AddImport,
+					Relevance: pkg.relevance,
+				},
+				Exports: exports,
+			})
+		},
 	}
-
-	results := make([]PackageExport, 0, len(pkgs))
-	for _, pkg := range pkgs {
-		fix := &ImportFix{
-			StmtInfo: ImportInfo{
-				ImportPath: pkg.importPathShort,
-				Name:       candidateImportName(pkg),
-			},
-			IdentName: pkg.packageName,
-			FixType:   AddImport,
-		}
-		var exports []string
-		if e, ok := stdlib[pkg.importPathShort]; ok {
-			exports = e
-		} else {
-			exports, err = loadExportsForPackage(context.Background(), env, completePackage, pkg)
-			if err != nil {
-				if env.Debug {
-					env.Logf("while completing %q, error loading exports from %q: %v", completePackage, pkg.importPathShort, err)
-				}
-				continue
-			}
-		}
-		sort.Strings(exports)
-		results = append(results, PackageExport{
-			Fix:     fix,
-			Exports: exports,
-		})
-	}
-
-	return results, nil
+	return getCandidatePkgs(ctx, callback, filename, filePkg, env)
 }
 
 // ProcessEnv contains environment variables and settings that affect the use of
@@ -720,20 +748,26 @@ type ProcessEnv struct {
 	LocalPrefix string
 	Debug       bool
 
+	BuildFlags []string
+
 	// If non-empty, these will be used instead of the
 	// process-wide values.
 	GOPATH, GOROOT, GO111MODULE, GOPROXY, GOFLAGS, GOSUMDB string
 	WorkingDir                                             string
 
-	// If true, use go/packages regardless of the environment.
-	ForceGoPackages bool
-
 	// Logf is the default logger for the ProcessEnv.
 	Logf func(format string, args ...interface{})
 
 	resolver Resolver
 }
 
+// CopyConfig copies the env's configuration into a new env.
+func (e *ProcessEnv) CopyConfig() *ProcessEnv {
+	copy := *e
+	copy.resolver = nil
+	return &copy
+}
+
 func (e *ProcessEnv) env() []string {
 	env := os.Environ()
 	add := func(k, v string) {
@@ -757,73 +791,55 @@ func (e *ProcessEnv) GetResolver() Resolver {
 	if e.resolver != nil {
 		return e.resolver
 	}
-	if e.ForceGoPackages {
-		e.resolver = &goPackagesResolver{env: e}
-		return e.resolver
-	}
-
-	out, err := e.invokeGo("env", "GOMOD")
+	out, err := e.invokeGo(context.TODO(), "env", "GOMOD")
 	if err != nil || len(bytes.TrimSpace(out.Bytes())) == 0 {
-		e.resolver = &gopathResolver{env: e}
+		e.resolver = newGopathResolver(e)
 		return e.resolver
 	}
-	e.resolver = &ModuleResolver{env: e}
+	e.resolver = newModuleResolver(e)
 	return e.resolver
 }
 
-func (e *ProcessEnv) newPackagesConfig(mode packages.LoadMode) *packages.Config {
-	return &packages.Config{
-		Mode: mode,
-		Dir:  e.WorkingDir,
-		Env:  e.env(),
-	}
-}
-
 func (e *ProcessEnv) buildContext() *build.Context {
 	ctx := build.Default
 	ctx.GOROOT = e.GOROOT
 	ctx.GOPATH = e.GOPATH
 
-	// As of Go 1.14, build.Context has a WorkingDir field
+	// As of Go 1.14, build.Context has a Dir field
 	// (see golang.org/issue/34860).
 	// Populate it only if present.
-	if wd := reflect.ValueOf(&ctx).Elem().FieldByName("WorkingDir"); wd.IsValid() && wd.Kind() == reflect.String {
-		wd.SetString(e.WorkingDir)
+	rc := reflect.ValueOf(&ctx).Elem()
+	dir := rc.FieldByName("Dir")
+	if !dir.IsValid() {
+		// Working drafts of Go 1.14 named the field "WorkingDir" instead.
+		// TODO(bcmills): Remove this case after the Go 1.14 beta has been released.
+		dir = rc.FieldByName("WorkingDir")
 	}
+	if dir.IsValid() && dir.Kind() == reflect.String {
+		dir.SetString(e.WorkingDir)
+	}
+
 	return &ctx
 }
 
-func (e *ProcessEnv) invokeGo(args ...string) (*bytes.Buffer, error) {
-	cmd := exec.Command("go", args...)
-	stdout := &bytes.Buffer{}
-	stderr := &bytes.Buffer{}
-	cmd.Stdout = stdout
-	cmd.Stderr = stderr
-	cmd.Env = e.env()
-	cmd.Dir = e.WorkingDir
-
-	if e.Debug {
-		defer func(start time.Time) { e.Logf("%s for %v", time.Since(start), cmdDebugStr(cmd)) }(time.Now())
+func (e *ProcessEnv) invokeGo(ctx context.Context, verb string, args ...string) (*bytes.Buffer, error) {
+	inv := gocommand.Invocation{
+		Verb:       verb,
+		Args:       args,
+		BuildFlags: e.BuildFlags,
+		Env:        e.env(),
+		Logf:       e.Logf,
+		WorkingDir: e.WorkingDir,
 	}
-	if err := cmd.Run(); err != nil {
-		return nil, fmt.Errorf("running go: %v (stderr:\n%s)", err, stderr)
-	}
-	return stdout, nil
-}
-
-func cmdDebugStr(cmd *exec.Cmd) string {
-	env := make(map[string]string)
-	for _, kv := range cmd.Env {
-		split := strings.Split(kv, "=")
-		k, v := split[0], split[1]
-		env[k] = v
-	}
-
-	return fmt.Sprintf("GOROOT=%v GOPATH=%v GO111MODULE=%v GOPROXY=%v PWD=%v go %v", env["GOROOT"], env["GOPATH"], env["GO111MODULE"], env["GOPROXY"], env["PWD"], cmd.Args)
+	return inv.Run(ctx)
 }
 
 func addStdlibCandidates(pass *pass, refs references) {
 	add := func(pkg string) {
+		// Prevent self-imports.
+		if path.Base(pkg) == pass.f.Name.Name && filepath.Join(pass.env.GOROOT, "src", pkg) == pass.srcDir {
+			return
+		}
 		exports := copyExports(stdlib[pkg])
 		pass.addCandidate(
 			&ImportInfo{ImportPath: pkg},
@@ -848,94 +864,65 @@ func addStdlibCandidates(pass *pass, refs references) {
 type Resolver interface {
 	// loadPackageNames loads the package names in importPaths.
 	loadPackageNames(importPaths []string, srcDir string) (map[string]string, error)
-	// scan finds (at least) the packages satisfying refs. If loadNames is true,
-	// package names will be set on the results, and dirs whose package name
-	// could not be determined will be excluded.
-	scan(refs references, loadNames bool, exclude []gopathwalk.RootType) ([]*pkg, error)
+	// scan works with callback to search for packages. See scanCallback for details.
+	scan(ctx context.Context, callback *scanCallback) error
 	// loadExports returns the set of exported symbols in the package at dir.
 	// loadExports may be called concurrently.
-	loadExports(ctx context.Context, pkg *pkg) (string, []string, error)
+	loadExports(ctx context.Context, pkg *pkg, includeTest bool) (string, []string, error)
+	// scoreImportPath returns the relevance for an import path.
+	scoreImportPath(ctx context.Context, path string) int
 
 	ClearForNewScan()
 }
 
-// gopackagesResolver implements resolver for GOPATH and module workspaces using go/packages.
-type goPackagesResolver struct {
-	env *ProcessEnv
-}
-
-func (r *goPackagesResolver) ClearForNewScan() {}
-
-func (r *goPackagesResolver) loadPackageNames(importPaths []string, srcDir string) (map[string]string, error) {
-	if len(importPaths) == 0 {
-		return nil, nil
-	}
-	cfg := r.env.newPackagesConfig(packages.LoadFiles)
-	pkgs, err := packages.Load(cfg, importPaths...)
-	if err != nil {
-		return nil, err
-	}
-	names := map[string]string{}
-	for _, pkg := range pkgs {
-		names[VendorlessPath(pkg.PkgPath)] = pkg.Name
-	}
-	// We may not have found all the packages. Guess the rest.
-	for _, path := range importPaths {
-		if _, ok := names[path]; ok {
-			continue
-		}
-		names[path] = ImportPathToAssumedName(path)
-	}
-	return names, nil
-
-}
-
-func (r *goPackagesResolver) scan(refs references, _ bool, _ []gopathwalk.RootType) ([]*pkg, error) {
-	var loadQueries []string
-	for pkgName := range refs {
-		loadQueries = append(loadQueries, "iamashamedtousethedisabledqueryname="+pkgName)
-	}
-	sort.Strings(loadQueries)
-	cfg := r.env.newPackagesConfig(packages.LoadFiles)
-	goPackages, err := packages.Load(cfg, loadQueries...)
-	if err != nil {
-		return nil, err
-	}
-
-	var scan []*pkg
-	for _, goPackage := range goPackages {
-		scan = append(scan, &pkg{
-			dir:             filepath.Dir(goPackage.CompiledGoFiles[0]),
-			importPathShort: VendorlessPath(goPackage.PkgPath),
-			goPackage:       goPackage,
-			packageName:     goPackage.Name,
-		})
-	}
-	return scan, nil
-}
-
-func (r *goPackagesResolver) loadExports(ctx context.Context, pkg *pkg) (string, []string, error) {
-	if pkg.goPackage == nil {
-		return "", nil, fmt.Errorf("goPackage not set")
-	}
-	var exports []string
-	fset := token.NewFileSet()
-	for _, fname := range pkg.goPackage.CompiledGoFiles {
-		f, err := parser.ParseFile(fset, fname, nil, 0)
-		if err != nil {
-			return "", nil, fmt.Errorf("parsing %s: %v", fname, err)
-		}
-		for name := range f.Scope.Objects {
-			if ast.IsExported(name) {
-				exports = append(exports, name)
-			}
-		}
-	}
-	return pkg.goPackage.Name, exports, nil
+// A scanCallback controls a call to scan and receives its results.
+// In general, minor errors will be silently discarded; a user should not
+// expect to receive a full series of calls for everything.
+type scanCallback struct {
+	// rootFound is called before scanning a new root dir. If it returns true,
+	// the root will be scanned. Returning false will not necessarily prevent
+	// directories from that root making it to dirFound.
+	rootFound func(gopathwalk.Root) bool
+	// dirFound is called when a directory is found that is possibly a Go package.
+	// pkg will be populated with everything except packageName.
+	// If it returns true, the package's name will be loaded.
+	dirFound func(pkg *pkg) bool
+	// packageNameLoaded is called when a package is found and its name is loaded.
+	// If it returns true, the package's exports will be loaded.
+	packageNameLoaded func(pkg *pkg) bool
+	// exportsLoaded is called when a package's exports have been loaded.
+	exportsLoaded func(pkg *pkg, exports []string)
 }
 
 func addExternalCandidates(pass *pass, refs references, filename string) error {
-	dirScan, err := pass.env.GetResolver().scan(refs, false, nil)
+	var mu sync.Mutex
+	found := make(map[string][]pkgDistance)
+	callback := &scanCallback{
+		rootFound: func(gopathwalk.Root) bool {
+			return true // We want everything.
+		},
+		dirFound: func(pkg *pkg) bool {
+			return pkgIsCandidate(filename, refs, pkg)
+		},
+		packageNameLoaded: func(pkg *pkg) bool {
+			if _, want := refs[pkg.packageName]; !want {
+				return false
+			}
+			if pkg.dir == pass.srcDir && pass.f.Name.Name == pkg.packageName {
+				// The candidate is in the same directory and has the
+				// same package name. Don't try to import ourselves.
+				return false
+			}
+			if !canUse(filename, pkg.dir) {
+				return false
+			}
+			mu.Lock()
+			defer mu.Unlock()
+			found[pkg.packageName] = append(found[pkg.packageName], pkgDistance{pkg, distance(pass.srcDir, pkg.dir)})
+			return false // We'll do our own loading after we sort.
+		},
+	}
+	err := pass.env.GetResolver().scan(context.Background(), callback)
 	if err != nil {
 		return err
 	}
@@ -962,7 +949,7 @@ func addExternalCandidates(pass *pass, refs references, filename string) error {
 		go func(pkgName string, symbols map[string]bool) {
 			defer wg.Done()
 
-			found, err := findImport(ctx, pass, dirScan, pkgName, symbols, filename)
+			found, err := findImport(ctx, pass, found[pkgName], pkgName, symbols, filename)
 
 			if err != nil {
 				firstErrOnce.Do(func() {
@@ -1033,24 +1020,36 @@ func ImportPathToAssumedName(importPath string) string {
 
 // gopathResolver implements resolver for GOPATH workspaces.
 type gopathResolver struct {
-	env   *ProcessEnv
-	cache *dirInfoCache
+	env      *ProcessEnv
+	walked   bool
+	cache    *dirInfoCache
+	scanSema chan struct{} // scanSema prevents concurrent scans.
 }
 
-func (r *gopathResolver) init() {
-	if r.cache == nil {
-		r.cache = &dirInfoCache{
-			dirs: map[string]*directoryPackageInfo{},
-		}
+func newGopathResolver(env *ProcessEnv) *gopathResolver {
+	r := &gopathResolver{
+		env: env,
+		cache: &dirInfoCache{
+			dirs:      map[string]*directoryPackageInfo{},
+			listeners: map[*int]cacheListener{},
+		},
+		scanSema: make(chan struct{}, 1),
 	}
+	r.scanSema <- struct{}{}
+	return r
 }
 
 func (r *gopathResolver) ClearForNewScan() {
-	r.cache = nil
+	<-r.scanSema
+	r.cache = &dirInfoCache{
+		dirs:      map[string]*directoryPackageInfo{},
+		listeners: map[*int]cacheListener{},
+	}
+	r.walked = false
+	r.scanSema <- struct{}{}
 }
 
 func (r *gopathResolver) loadPackageNames(importPaths []string, srcDir string) (map[string]string, error) {
-	r.init()
 	names := map[string]string{}
 	for _, path := range importPaths {
 		names[path] = importPathToName(r.env, path, srcDir)
@@ -1130,7 +1129,6 @@ func packageDirToName(dir string) (packageName string, err error) {
 }
 
 type pkg struct {
-	goPackage       *packages.Package
 	dir             string // absolute file path to pkg directory ("/usr/lib/go/src/net/http")
 	importPathShort string // vendorless import path ("net/http", "a/b")
 	packageName     string // package name loaded from source if requested
@@ -1178,8 +1176,7 @@ func distance(basepath, targetpath string) int {
 	return strings.Count(p, string(filepath.Separator)) + 1
 }
 
-func (r *gopathResolver) scan(_ references, loadNames bool, exclude []gopathwalk.RootType) ([]*pkg, error) {
-	r.init()
+func (r *gopathResolver) scan(ctx context.Context, callback *scanCallback) error {
 	add := func(root gopathwalk.Root, dir string) {
 		// We assume cached directories have not changed. We can skip them and their
 		// children.
@@ -1196,56 +1193,84 @@ func (r *gopathResolver) scan(_ references, loadNames bool, exclude []gopathwalk
 		}
 		r.cache.Store(dir, info)
 	}
-	roots := filterRoots(gopathwalk.SrcDirsRoots(r.env.buildContext()), exclude)
-	gopathwalk.Walk(roots, add, gopathwalk.Options{Debug: r.env.Debug, ModulesEnabled: false})
-	var result []*pkg
-	for _, dir := range r.cache.Keys() {
-		info, ok := r.cache.Load(dir)
-		if !ok {
-			continue
-		}
-		if loadNames {
-			var err error
-			info, err = r.cache.CachePackageName(info)
-			if err != nil {
-				continue
-			}
+	processDir := func(info directoryPackageInfo) {
+		// Skip this directory if we were not able to get the package information successfully.
+		if scanned, err := info.reachedStatus(directoryScanned); !scanned || err != nil {
+			return
 		}
 
 		p := &pkg{
 			importPathShort: info.nonCanonicalImportPath,
-			dir:             dir,
-			relevance:       1,
-			packageName:     info.packageName,
+			dir:             info.dir,
+			relevance:       MaxRelevance - 1,
 		}
 		if info.rootType == gopathwalk.RootGOROOT {
-			p.relevance = 0
+			p.relevance = MaxRelevance
+		}
+
+		if !callback.dirFound(p) {
+			return
+		}
+		var err error
+		p.packageName, err = r.cache.CachePackageName(info)
+		if err != nil {
+			return
+		}
+
+		if !callback.packageNameLoaded(p) {
+			return
+		}
+		if _, exports, err := r.loadExports(ctx, p, false); err == nil {
+			callback.exportsLoaded(p, exports)
 		}
-		result = append(result, p)
 	}
-	return result, nil
+	stop := r.cache.ScanAndListen(ctx, processDir)
+	defer stop()
+	// The callback is not necessarily safe to use in the goroutine below. Process roots eagerly.
+	roots := filterRoots(gopathwalk.SrcDirsRoots(r.env.buildContext()), callback.rootFound)
+	// We can't cancel walks, because we need them to finish to have a usable
+	// cache. Instead, run them in a separate goroutine and detach.
+	scanDone := make(chan struct{})
+	go func() {
+		select {
+		case <-ctx.Done():
+			return
+		case <-r.scanSema:
+		}
+		defer func() { r.scanSema <- struct{}{} }()
+		gopathwalk.Walk(roots, add, gopathwalk.Options{Debug: r.env.Debug, ModulesEnabled: false})
+		close(scanDone)
+	}()
+	select {
+	case <-ctx.Done():
+	case <-scanDone:
+	}
+	return nil
 }
 
-func filterRoots(roots []gopathwalk.Root, exclude []gopathwalk.RootType) []gopathwalk.Root {
+func (r *gopathResolver) scoreImportPath(ctx context.Context, path string) int {
+	if _, ok := stdlib[path]; ok {
+		return MaxRelevance
+	}
+	return MaxRelevance - 1
+}
+
+func filterRoots(roots []gopathwalk.Root, include func(gopathwalk.Root) bool) []gopathwalk.Root {
 	var result []gopathwalk.Root
-outer:
 	for _, root := range roots {
-		for _, i := range exclude {
-			if i == root.Type {
-				continue outer
-			}
+		if !include(root) {
+			continue
 		}
 		result = append(result, root)
 	}
 	return result
 }
 
-func (r *gopathResolver) loadExports(ctx context.Context, pkg *pkg) (string, []string, error) {
-	r.init()
-	if info, ok := r.cache.Load(pkg.dir); ok {
+func (r *gopathResolver) loadExports(ctx context.Context, pkg *pkg, includeTest bool) (string, []string, error) {
+	if info, ok := r.cache.Load(pkg.dir); ok && !includeTest {
 		return r.cache.CacheExports(ctx, r.env, info)
 	}
-	return loadExportsFromFiles(ctx, r.env, pkg.dir)
+	return loadExportsFromFiles(ctx, r.env, pkg.dir, includeTest)
 }
 
 // VendorlessPath returns the devendorized version of the import path ipath.
@@ -1261,7 +1286,7 @@ func VendorlessPath(ipath string) string {
 	return ipath
 }
 
-func loadExportsFromFiles(ctx context.Context, env *ProcessEnv, dir string) (string, []string, error) {
+func loadExportsFromFiles(ctx context.Context, env *ProcessEnv, dir string, includeTest bool) (string, []string, error) {
 	var exports []string
 
 	// Look for non-test, buildable .go files which could provide exports.
@@ -1272,7 +1297,7 @@ func loadExportsFromFiles(ctx context.Context, env *ProcessEnv, dir string) (str
 	var files []os.FileInfo
 	for _, fi := range all {
 		name := fi.Name()
-		if !strings.HasSuffix(name, ".go") || strings.HasSuffix(name, "_test.go") {
+		if !strings.HasSuffix(name, ".go") || (!includeTest && strings.HasSuffix(name, "_test.go")) {
 			continue
 		}
 		match, err := env.buildContext().MatchFile(dir, fi.Name())
@@ -1305,6 +1330,10 @@ func loadExportsFromFiles(ctx context.Context, env *ProcessEnv, dir string) (str
 			// handled by MatchFile above.
 			continue
 		}
+		if includeTest && strings.HasSuffix(f.Name.Name, "_test") {
+			// x_test package. We want internal test files only.
+			continue
+		}
 		pkgName = f.Name.Name
 		for name := range f.Scope.Objects {
 			if ast.IsExported(name) {
@@ -1323,29 +1352,7 @@ func loadExportsFromFiles(ctx context.Context, env *ProcessEnv, dir string) (str
 
 // findImport searches for a package with the given symbols.
 // If no package is found, findImport returns ("", false, nil)
-func findImport(ctx context.Context, pass *pass, dirScan []*pkg, pkgName string, symbols map[string]bool, filename string) (*pkg, error) {
-	pkgDir, err := filepath.Abs(filename)
-	if err != nil {
-		return nil, err
-	}
-	pkgDir = filepath.Dir(pkgDir)
-
-	// Find candidate packages, looking only at their directory names first.
-	var candidates []pkgDistance
-	for _, pkg := range dirScan {
-		if pkg.dir == pkgDir && pass.f.Name.Name == pkgName {
-			// The candidate is in the same directory and has the
-			// same package name. Don't try to import ourselves.
-			continue
-		}
-		if pkgIsCandidate(filename, pkgName, pkg) {
-			candidates = append(candidates, pkgDistance{
-				pkg:      pkg,
-				distance: distance(pkgDir, pkg.dir),
-			})
-		}
-	}
-
+func findImport(ctx context.Context, pass *pass, candidates []pkgDistance, pkgName string, symbols map[string]bool, filename string) (*pkg, error) {
 	// Sort the candidates by their import package length,
 	// assuming that shorter package names are better than long
 	// ones.  Note that this sorts by the de-vendored name, so
@@ -1358,7 +1365,6 @@ func findImport(ctx context.Context, pass *pass, dirScan []*pkg, pkgName string,
 	}
 
 	// Collect exports for packages with matching names.
-
 	rescv := make([]chan *pkg, len(candidates))
 	for i := range candidates {
 		rescv[i] = make(chan *pkg, 1)
@@ -1393,7 +1399,9 @@ func findImport(ctx context.Context, pass *pass, dirScan []*pkg, pkgName string,
 				if pass.env.Debug {
 					pass.env.Logf("loading exports in dir %s (seeking package %s)", c.pkg.dir, pkgName)
 				}
-				exports, err := loadExportsForPackage(ctx, pass.env, pkgName, c.pkg)
+				// If we're an x_test, load the package under test's test variant.
+				includeTest := strings.HasSuffix(pass.f.Name.Name, "_test") && c.pkg.dir == pass.srcDir
+				_, exports, err := pass.env.GetResolver().loadExports(ctx, c.pkg, includeTest)
 				if err != nil {
 					if pass.env.Debug {
 						pass.env.Logf("loading exports in dir %s (seeking package %s): %v", c.pkg.dir, pkgName, err)
@@ -1430,17 +1438,6 @@ func findImport(ctx context.Context, pass *pass, dirScan []*pkg, pkgName string,
 	return nil, nil
 }
 
-func loadExportsForPackage(ctx context.Context, env *ProcessEnv, expectPkg string, pkg *pkg) ([]string, error) {
-	pkgName, exports, err := env.GetResolver().loadExports(ctx, pkg)
-	if err != nil {
-		return nil, err
-	}
-	if expectPkg != pkgName {
-		return nil, fmt.Errorf("dir %v is package %v, wanted %v", pkg.dir, pkgName, expectPkg)
-	}
-	return exports, err
-}
-
 // pkgIsCandidate reports whether pkg is a candidate for satisfying the
 // finding which package pkgIdent in the file named by filename is trying
 // to refer to.
@@ -1453,7 +1450,7 @@ func loadExportsForPackage(ctx context.Context, env *ProcessEnv, expectPkg strin
 // filename is the file being formatted.
 // pkgIdent is the package being searched for, like "client" (if
 // searching for "client.New")
-func pkgIsCandidate(filename, pkgIdent string, pkg *pkg) bool {
+func pkgIsCandidate(filename string, refs references, pkg *pkg) bool {
 	// Check "internal" and "vendor" visibility:
 	if !canUse(filename, pkg.dir) {
 		return false
@@ -1471,17 +1468,18 @@ func pkgIsCandidate(filename, pkgIdent string, pkg *pkg) bool {
 	// "bar", which is strongly discouraged
 	// anyway. There's no reason goimports needs
 	// to be slow just to accommodate that.
-	lastTwo := lastTwoComponents(pkg.importPathShort)
-	if strings.Contains(lastTwo, pkgIdent) {
-		return true
-	}
-	if hasHyphenOrUpperASCII(lastTwo) && !hasHyphenOrUpperASCII(pkgIdent) {
-		lastTwo = lowerASCIIAndRemoveHyphen(lastTwo)
+	for pkgIdent := range refs {
+		lastTwo := lastTwoComponents(pkg.importPathShort)
 		if strings.Contains(lastTwo, pkgIdent) {
 			return true
 		}
+		if hasHyphenOrUpperASCII(lastTwo) && !hasHyphenOrUpperASCII(pkgIdent) {
+			lastTwo = lowerASCIIAndRemoveHyphen(lastTwo)
+			if strings.Contains(lastTwo, pkgIdent) {
+				return true
+			}
+		}
 	}
-
 	return false
 }
 

vendor/golang.org/x/tools/internal/imports/imports.go

@@ -11,6 +11,7 @@ package imports
 import (
 	"bufio"
 	"bytes"
+	"context"
 	"fmt"
 	"go/ast"
 	"go/build"
@@ -21,6 +22,7 @@ import (
 	"io"
 	"io/ioutil"
 	"log"
+	"os"
 	"regexp"
 	"strconv"
 	"strings"
@@ -114,23 +116,23 @@ func ApplyFixes(fixes []*ImportFix, filename string, src []byte, opt *Options, e
 	return formatFile(fileSet, file, src, nil, opt)
 }
 
-// GetAllCandidates gets all of the standard library candidate packages to import in
-// sorted order on import path.
-func GetAllCandidates(filename string, opt *Options) (pkgs []ImportFix, err error) {
-	_, opt, err = initialize(filename, nil, opt)
+// GetAllCandidates gets all of the packages starting with prefix that can be
+// imported by filename, sorted by import path.
+func GetAllCandidates(ctx context.Context, callback func(ImportFix), searchPrefix, filename, filePkg string, opt *Options) error {
+	_, opt, err := initialize(filename, []byte{}, opt)
 	if err != nil {
-		return nil, err
+		return err
 	}
-	return getAllCandidates(filename, opt.Env)
+	return getAllCandidates(ctx, callback, searchPrefix, filename, filePkg, opt.Env)
 }
 
 // GetPackageExports returns all known packages with name pkg and their exports.
-func GetPackageExports(pkg, filename string, opt *Options) (exports []PackageExport, err error) {
-	_, opt, err = initialize(filename, nil, opt)
+func GetPackageExports(ctx context.Context, callback func(PackageExport), searchPkg, filename, filePkg string, opt *Options) error {
+	_, opt, err := initialize(filename, []byte{}, opt)
 	if err != nil {
-		return nil, err
+		return err
 	}
-	return getPackageExports(pkg, filename, opt.Env)
+	return getPackageExports(ctx, callback, searchPkg, filename, filePkg, opt.Env)
 }
 
 // initialize sets the values for opt and src.
@@ -145,8 +147,12 @@ func initialize(filename string, src []byte, opt *Options) ([]byte, *Options, er
 	// Set the env if the user has not provided it.
 	if opt.Env == nil {
 		opt.Env = &ProcessEnv{
-			GOPATH: build.Default.GOPATH,
-			GOROOT: build.Default.GOROOT,
+			GOPATH:      build.Default.GOPATH,
+			GOROOT:      build.Default.GOROOT,
+			GOFLAGS:     os.Getenv("GOFLAGS"),
+			GO111MODULE: os.Getenv("GO111MODULE"),
+			GOPROXY:     os.Getenv("GOPROXY"),
+			GOSUMDB:     os.Getenv("GOSUMDB"),
 		}
 	}
 

vendor/golang.org/x/tools/internal/imports/mod.go

@@ -13,11 +13,10 @@ import (
 	"sort"
 	"strconv"
 	"strings"
-	"sync"
 
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
 	"golang.org/x/tools/internal/gopathwalk"
-	"golang.org/x/tools/internal/module"
-	"golang.org/x/tools/internal/semver"
 )
 
 // ModuleResolver implements resolver for modules using the go command as little
@@ -26,11 +25,14 @@ type ModuleResolver struct {
 	env            *ProcessEnv
 	moduleCacheDir string
 	dummyVendorMod *ModuleJSON // If vendoring is enabled, the pseudo-module that represents the /vendor directory.
+	roots          []gopathwalk.Root
+	scanSema       chan struct{} // scanSema prevents concurrent scans and guards scannedRoots.
+	scannedRoots   map[gopathwalk.Root]bool
 
-	Initialized   bool
-	Main          *ModuleJSON
-	ModsByModPath []*ModuleJSON // All modules, ordered by # of path components in module Path...
-	ModsByDir     []*ModuleJSON // ...or Dir.
+	initialized   bool
+	main          *ModuleJSON
+	modsByModPath []*ModuleJSON // All modules, ordered by # of path components in module Path...
+	modsByDir     []*ModuleJSON // ...or Dir.
 
 	// moduleCacheCache stores information about the module cache.
 	moduleCacheCache *dirInfoCache
@@ -41,13 +43,23 @@ 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
 }
 
+func newModuleResolver(e *ProcessEnv) *ModuleResolver {
+	r := &ModuleResolver{
+		env:      e,
+		scanSema: make(chan struct{}, 1),
+	}
+	r.scanSema <- struct{}{}
+	return r
+}
+
 func (r *ModuleResolver) init() error {
-	if r.Initialized {
+	if r.initialized {
 		return nil
 	}
 	mainMod, vendorEnabled, err := vendorEnabled(r.env)
@@ -58,13 +70,13 @@ func (r *ModuleResolver) init() error {
 	if mainMod != nil && vendorEnabled {
 		// Vendor mode is on, so all the non-Main modules are irrelevant,
 		// and we need to search /vendor for everything.
-		r.Main = mainMod
+		r.main = mainMod
 		r.dummyVendorMod = &ModuleJSON{
 			Path: "",
 			Dir:  filepath.Join(mainMod.Dir, "vendor"),
 		}
-		r.ModsByModPath = []*ModuleJSON{mainMod, r.dummyVendorMod}
-		r.ModsByDir = []*ModuleJSON{mainMod, r.dummyVendorMod}
+		r.modsByModPath = []*ModuleJSON{mainMod, r.dummyVendorMod}
+		r.modsByDir = []*ModuleJSON{mainMod, r.dummyVendorMod}
 	} else {
 		// Vendor mode is off, so run go list -m ... to find everything.
 		r.initAllMods()
@@ -72,35 +84,69 @@ func (r *ModuleResolver) init() error {
 
 	r.moduleCacheDir = filepath.Join(filepath.SplitList(r.env.GOPATH)[0], "/pkg/mod")
 
-	sort.Slice(r.ModsByModPath, func(i, j int) bool {
+	sort.Slice(r.modsByModPath, func(i, j int) bool {
 		count := func(x int) int {
-			return strings.Count(r.ModsByModPath[x].Path, "/")
+			return strings.Count(r.modsByModPath[x].Path, "/")
 		}
 		return count(j) < count(i) // descending order
 	})
-	sort.Slice(r.ModsByDir, func(i, j int) bool {
+	sort.Slice(r.modsByDir, func(i, j int) bool {
 		count := func(x int) int {
-			return strings.Count(r.ModsByDir[x].Dir, "/")
+			return strings.Count(r.modsByDir[x].Dir, "/")
 		}
 		return count(j) < count(i) // descending order
 	})
 
+	r.roots = []gopathwalk.Root{
+		{filepath.Join(r.env.GOROOT, "/src"), gopathwalk.RootGOROOT},
+	}
+	if r.main != nil {
+		r.roots = append(r.roots, gopathwalk.Root{r.main.Dir, gopathwalk.RootCurrentModule})
+	}
+	if vendorEnabled {
+		r.roots = append(r.roots, gopathwalk.Root{r.dummyVendorMod.Dir, gopathwalk.RootOther})
+	} else {
+		addDep := func(mod *ModuleJSON) {
+			if mod.Replace == nil {
+				// This is redundant with the cache, but we'll skip it cheaply enough.
+				r.roots = append(r.roots, gopathwalk.Root{mod.Dir, gopathwalk.RootModuleCache})
+			} else {
+				r.roots = append(r.roots, gopathwalk.Root{mod.Dir, gopathwalk.RootOther})
+			}
+		}
+		// Walk dependent modules before scanning the full mod cache, direct deps first.
+		for _, mod := range r.modsByModPath {
+			if !mod.Indirect && !mod.Main {
+				addDep(mod)
+			}
+		}
+		for _, mod := range r.modsByModPath {
+			if mod.Indirect && !mod.Main {
+				addDep(mod)
+			}
+		}
+		r.roots = append(r.roots, gopathwalk.Root{r.moduleCacheDir, gopathwalk.RootModuleCache})
+	}
+
+	r.scannedRoots = map[gopathwalk.Root]bool{}
 	if r.moduleCacheCache == nil {
 		r.moduleCacheCache = &dirInfoCache{
-			dirs: map[string]*directoryPackageInfo{},
+			dirs:      map[string]*directoryPackageInfo{},
+			listeners: map[*int]cacheListener{},
 		}
 	}
 	if r.otherCache == nil {
 		r.otherCache = &dirInfoCache{
-			dirs: map[string]*directoryPackageInfo{},
+			dirs:      map[string]*directoryPackageInfo{},
+			listeners: map[*int]cacheListener{},
 		}
 	}
-	r.Initialized = true
+	r.initialized = true
 	return nil
 }
 
 func (r *ModuleResolver) initAllMods() error {
-	stdout, err := r.env.invokeGo("list", "-m", "-json", "...")
+	stdout, err := r.env.invokeGo(context.TODO(), "list", "-m", "-json", "...")
 	if err != nil {
 		return err
 	}
@@ -116,27 +162,37 @@ func (r *ModuleResolver) initAllMods() error {
 			// Can't do anything with a module that's not downloaded.
 			continue
 		}
-		r.ModsByModPath = append(r.ModsByModPath, mod)
-		r.ModsByDir = append(r.ModsByDir, mod)
+		// golang/go#36193: the go command doesn't always clean paths.
+		mod.Dir = filepath.Clean(mod.Dir)
+		r.modsByModPath = append(r.modsByModPath, mod)
+		r.modsByDir = append(r.modsByDir, mod)
 		if mod.Main {
-			r.Main = mod
+			r.main = mod
 		}
 	}
 	return nil
 }
 
 func (r *ModuleResolver) ClearForNewScan() {
+	<-r.scanSema
+	r.scannedRoots = map[gopathwalk.Root]bool{}
 	r.otherCache = &dirInfoCache{
-		dirs: map[string]*directoryPackageInfo{},
+		dirs:      map[string]*directoryPackageInfo{},
+		listeners: map[*int]cacheListener{},
 	}
+	r.scanSema <- struct{}{}
 }
 
 func (r *ModuleResolver) ClearForNewMod() {
-	env := r.env
+	<-r.scanSema
 	*r = ModuleResolver{
-		env: env,
+		env:              r.env,
+		moduleCacheCache: r.moduleCacheCache,
+		otherCache:       r.otherCache,
+		scanSema:         r.scanSema,
 	}
 	r.init()
+	r.scanSema <- struct{}{}
 }
 
 // findPackage returns the module and directory that contains the package at
@@ -144,7 +200,7 @@ func (r *ModuleResolver) ClearForNewMod() {
 func (r *ModuleResolver) findPackage(importPath string) (*ModuleJSON, string) {
 	// This can't find packages in the stdlib, but that's harmless for all
 	// the existing code paths.
-	for _, m := range r.ModsByModPath {
+	for _, m := range r.modsByModPath {
 		if !strings.HasPrefix(importPath, m.Path) {
 			continue
 		}
@@ -211,7 +267,7 @@ func (r *ModuleResolver) cacheKeys() []string {
 }
 
 // cachePackageName caches the package name for a dir already in the cache.
-func (r *ModuleResolver) cachePackageName(info directoryPackageInfo) (directoryPackageInfo, error) {
+func (r *ModuleResolver) cachePackageName(info directoryPackageInfo) (string, error) {
 	if info.rootType == gopathwalk.RootModuleCache {
 		return r.moduleCacheCache.CachePackageName(info)
 	}
@@ -238,7 +294,7 @@ func (r *ModuleResolver) findModuleByDir(dir string) *ModuleJSON {
 	// - in /vendor/ in -mod=vendor mode.
 	//    - nested module? Dunno.
 	// Rumor has it that replace targets cannot contain other replace targets.
-	for _, m := range r.ModsByDir {
+	for _, m := range r.modsByDir {
 		if !strings.HasPrefix(dir, m.Dir) {
 			continue
 		}
@@ -333,41 +389,49 @@ func (r *ModuleResolver) loadPackageNames(importPaths []string, srcDir string) (
 	return names, nil
 }
 
-func (r *ModuleResolver) scan(_ references, loadNames bool, exclude []gopathwalk.RootType) ([]*pkg, error) {
+func (r *ModuleResolver) scan(ctx context.Context, callback *scanCallback) error {
 	if err := r.init(); err != nil {
-		return nil, err
+		return err
 	}
 
-	// Walk GOROOT, GOPATH/pkg/mod, and the main module.
-	roots := []gopathwalk.Root{
-		{filepath.Join(r.env.GOROOT, "/src"), gopathwalk.RootGOROOT},
-	}
-	if r.Main != nil {
-		roots = append(roots, gopathwalk.Root{r.Main.Dir, gopathwalk.RootCurrentModule})
-	}
-	if r.dummyVendorMod != nil {
-		roots = append(roots, gopathwalk.Root{r.dummyVendorMod.Dir, gopathwalk.RootOther})
-	} else {
-		roots = append(roots, gopathwalk.Root{r.moduleCacheDir, gopathwalk.RootModuleCache})
-		// Walk replace targets, just in case they're not in any of the above.
-		for _, mod := range r.ModsByModPath {
-			if mod.Replace != nil {
-				roots = append(roots, gopathwalk.Root{mod.Dir, gopathwalk.RootOther})
-			}
+	processDir := func(info directoryPackageInfo) {
+		// Skip this directory if we were not able to get the package information successfully.
+		if scanned, err := info.reachedStatus(directoryScanned); !scanned || err != nil {
+			return
 		}
+		pkg, err := r.canonicalize(info)
+		if err != nil {
+			return
+		}
+
+		if !callback.dirFound(pkg) {
+			return
+		}
+		pkg.packageName, err = r.cachePackageName(info)
+		if err != nil {
+			return
+		}
+
+		if !callback.packageNameLoaded(pkg) {
+			return
+		}
+		_, exports, err := r.loadExports(ctx, pkg, false)
+		if err != nil {
+			return
+		}
+		callback.exportsLoaded(pkg, exports)
 	}
 
-	roots = filterRoots(roots, exclude)
+	// Start processing everything in the cache, and listen for the new stuff
+	// we discover in the walk below.
+	stop1 := r.moduleCacheCache.ScanAndListen(ctx, processDir)
+	defer stop1()
+	stop2 := r.otherCache.ScanAndListen(ctx, processDir)
+	defer stop2()
 
-	var result []*pkg
-	var mu sync.Mutex
-
-	// We assume cached directories have not changed. We can skip them and their
-	// children.
+	// We assume cached directories are fully cached, including all their
+	// children, and have not changed. We can skip them.
 	skip := func(root gopathwalk.Root, dir string) bool {
-		mu.Lock()
-		defer mu.Unlock()
-
 		info, ok := r.cacheLoad(dir)
 		if !ok {
 			return false
@@ -379,44 +443,64 @@ func (r *ModuleResolver) scan(_ references, loadNames bool, exclude []gopathwalk
 		return packageScanned
 	}
 
-	// Add anything new to the cache. We'll process everything in it below.
+	// Add anything new to the cache, and process it if we're still listening.
 	add := func(root gopathwalk.Root, dir string) {
-		mu.Lock()
-		defer mu.Unlock()
-
 		r.cacheStore(r.scanDirForPackage(root, dir))
 	}
 
-	gopathwalk.WalkSkip(roots, add, skip, gopathwalk.Options{Debug: r.env.Debug, ModulesEnabled: true})
-
-	// Everything we already had, and everything new, is now in the cache.
-	for _, dir := range r.cacheKeys() {
-		info, ok := r.cacheLoad(dir)
-		if !ok {
-			continue
+	// r.roots and the callback are not necessarily safe to use in the
+	// goroutine below. Process them eagerly.
+	roots := filterRoots(r.roots, callback.rootFound)
+	// We can't cancel walks, because we need them to finish to have a usable
+	// cache. Instead, run them in a separate goroutine and detach.
+	scanDone := make(chan struct{})
+	go func() {
+		select {
+		case <-ctx.Done():
+			return
+		case <-r.scanSema:
 		}
+		defer func() { r.scanSema <- struct{}{} }()
+		// We have the lock on r.scannedRoots, and no other scans can run.
+		for _, root := range roots {
+			if ctx.Err() != nil {
+				return
+			}
 
-		// Skip this directory if we were not able to get the package information successfully.
-		if scanned, err := info.reachedStatus(directoryScanned); !scanned || err != nil {
-			continue
-		}
-
-		// If we want package names, make sure the cache has them.
-		if loadNames {
-			var err error
-			if info, err = r.cachePackageName(info); err != nil {
+			if r.scannedRoots[root] {
 				continue
 			}
+			gopathwalk.WalkSkip([]gopathwalk.Root{root}, add, skip, gopathwalk.Options{Debug: r.env.Debug, ModulesEnabled: true})
+			r.scannedRoots[root] = true
 		}
-
-		res, err := r.canonicalize(info)
-		if err != nil {
-			continue
-		}
-		result = append(result, res)
+		close(scanDone)
+	}()
+	select {
+	case <-ctx.Done():
+	case <-scanDone:
 	}
+	return nil
+}
 
-	return result, nil
+func (r *ModuleResolver) scoreImportPath(ctx context.Context, path string) int {
+	if _, ok := stdlib[path]; ok {
+		return MaxRelevance
+	}
+	mod, _ := r.findPackage(path)
+	return modRelevance(mod)
+}
+
+func modRelevance(mod *ModuleJSON) int {
+	switch {
+	case mod == nil: // out of scope
+		return MaxRelevance - 4
+	case mod.Indirect:
+		return MaxRelevance - 3
+	case !mod.Main:
+		return MaxRelevance - 2
+	default:
+		return MaxRelevance - 1 // main module ties with stdlib
+	}
 }
 
 // canonicalize gets the result of canonicalizing the packages using the results
@@ -428,15 +512,14 @@ func (r *ModuleResolver) canonicalize(info directoryPackageInfo) (*pkg, error) {
 			importPathShort: info.nonCanonicalImportPath,
 			dir:             info.dir,
 			packageName:     path.Base(info.nonCanonicalImportPath),
-			relevance:       0,
+			relevance:       MaxRelevance,
 		}, nil
 	}
 
 	importPath := info.nonCanonicalImportPath
-	relevance := 2
+	mod := r.findModuleByDir(info.dir)
 	// Check if the directory is underneath a module that's in scope.
-	if mod := r.findModuleByDir(info.dir); mod != nil {
-		relevance = 1
+	if mod != nil {
 		// It is. If dir is the target of a replace directive,
 		// our guessed import path is wrong. Use the real one.
 		if mod.Dir == info.dir {
@@ -445,15 +528,16 @@ func (r *ModuleResolver) canonicalize(info directoryPackageInfo) (*pkg, error) {
 			dirInMod := info.dir[len(mod.Dir)+len("/"):]
 			importPath = path.Join(mod.Path, filepath.ToSlash(dirInMod))
 		}
-	} else if info.needsReplace {
+	} else if !strings.HasPrefix(importPath, info.moduleName) {
+		// The module's name doesn't match the package's import path. It
+		// probably needs a replace directive we don't have.
 		return nil, fmt.Errorf("package in %q is not valid without a replace statement", info.dir)
 	}
 
 	res := &pkg{
 		importPathShort: importPath,
 		dir:             info.dir,
-		packageName:     info.packageName, // may not be populated if the caller didn't ask for it
-		relevance:       relevance,
+		relevance:       modRelevance(mod),
 	}
 	// We may have discovered a package that has a different version
 	// in scope already. Canonicalize to that one if possible.
@@ -463,14 +547,14 @@ func (r *ModuleResolver) canonicalize(info directoryPackageInfo) (*pkg, error) {
 	return res, nil
 }
 
-func (r *ModuleResolver) loadExports(ctx context.Context, pkg *pkg) (string, []string, error) {
+func (r *ModuleResolver) loadExports(ctx context.Context, pkg *pkg, includeTest bool) (string, []string, error) {
 	if err := r.init(); err != nil {
 		return "", nil, err
 	}
-	if info, ok := r.cacheLoad(pkg.dir); ok {
+	if info, ok := r.cacheLoad(pkg.dir); ok && !includeTest {
 		return r.cacheExports(ctx, r.env, info)
 	}
-	return loadExportsFromFiles(ctx, r.env, pkg.dir)
+	return loadExportsFromFiles(ctx, r.env, pkg.dir, includeTest)
 }
 
 func (r *ModuleResolver) scanDirForPackage(root gopathwalk.Root, dir string) directoryPackageInfo {
@@ -488,7 +572,7 @@ func (r *ModuleResolver) scanDirForPackage(root gopathwalk.Root, dir string) dir
 	}
 	switch root.Type {
 	case gopathwalk.RootCurrentModule:
-		importPath = path.Join(r.Main.Path, filepath.ToSlash(subdir))
+		importPath = path.Join(r.main.Path, filepath.ToSlash(subdir))
 	case gopathwalk.RootModuleCache:
 		matches := modCacheRegexp.FindStringSubmatch(subdir)
 		if len(matches) == 0 {
@@ -497,7 +581,7 @@ func (r *ModuleResolver) scanDirForPackage(root gopathwalk.Root, dir string) dir
 				err:    fmt.Errorf("invalid module cache path: %v", subdir),
 			}
 		}
-		modPath, err := module.DecodePath(filepath.ToSlash(matches[1]))
+		modPath, err := module.UnescapePath(filepath.ToSlash(matches[1]))
 		if err != nil {
 			if r.env.Debug {
 				r.env.Logf("decoding module cache path %q: %v", subdir, err)
@@ -516,7 +600,6 @@ func (r *ModuleResolver) scanDirForPackage(root gopathwalk.Root, dir string) dir
 		dir:                    dir,
 		rootType:               root.Type,
 		nonCanonicalImportPath: importPath,
-		needsReplace:           false,
 		moduleDir:              modDir,
 		moduleName:             modName,
 	}
@@ -524,14 +607,6 @@ func (r *ModuleResolver) scanDirForPackage(root gopathwalk.Root, dir string) dir
 		// stdlib packages are always in scope, despite the confusing go.mod
 		return result
 	}
-	// Check that this package is not obviously impossible to import.
-	if !strings.HasPrefix(importPath, modName) {
-		// The module's declared path does not match
-		// its expected path. It probably needs a
-		// replace directive we don't have.
-		result.needsReplace = true
-	}
-
 	return result
 }
 
@@ -624,7 +699,7 @@ func getMainModuleAnd114(env *ProcessEnv) (*ModuleJSON, bool, error) {
 {{.GoVersion}}
 {{range context.ReleaseTags}}{{if eq . "go1.14"}}{{.}}{{end}}{{end}}
 `
-	stdout, err := env.invokeGo("list", "-m", "-f", format)
+	stdout, err := env.invokeGo(context.TODO(), "list", "-m", "-f", format)
 	if err != nil {
 		return nil, false, nil
 	}

vendor/golang.org/x/tools/internal/imports/mod_cache.go

@@ -49,10 +49,6 @@ type directoryPackageInfo struct {
 	// nonCanonicalImportPath is the package's expected import path. It may
 	// not actually be importable at that path.
 	nonCanonicalImportPath string
-	// needsReplace is true if the nonCanonicalImportPath does not match the
-	// module's declared path, making it impossible to import without a
-	// replace directive.
-	needsReplace bool
 
 	// Module-related information.
 	moduleDir  string // The directory that is the module root of this dir.
@@ -97,15 +93,86 @@ func (info *directoryPackageInfo) reachedStatus(target directoryPackageStatus) (
 type dirInfoCache struct {
 	mu sync.Mutex
 	// dirs stores information about packages in directories, keyed by absolute path.
-	dirs map[string]*directoryPackageInfo
+	dirs      map[string]*directoryPackageInfo
+	listeners map[*int]cacheListener
+}
+
+type cacheListener func(directoryPackageInfo)
+
+// ScanAndListen calls listener on all the items in the cache, and on anything
+// newly added. The returned stop function waits for all in-flight callbacks to
+// finish and blocks new ones.
+func (d *dirInfoCache) ScanAndListen(ctx context.Context, listener cacheListener) func() {
+	ctx, cancel := context.WithCancel(ctx)
+
+	// Flushing out all the callbacks is tricky without knowing how many there
+	// are going to be. Setting an arbitrary limit makes it much easier.
+	const maxInFlight = 10
+	sema := make(chan struct{}, maxInFlight)
+	for i := 0; i < maxInFlight; i++ {
+		sema <- struct{}{}
+	}
+
+	cookie := new(int) // A unique ID we can use for the listener.
+
+	// We can't hold mu while calling the listener.
+	d.mu.Lock()
+	var keys []string
+	for key := range d.dirs {
+		keys = append(keys, key)
+	}
+	d.listeners[cookie] = func(info directoryPackageInfo) {
+		select {
+		case <-ctx.Done():
+			return
+		case <-sema:
+		}
+		listener(info)
+		sema <- struct{}{}
+	}
+	d.mu.Unlock()
+
+	stop := func() {
+		cancel()
+		d.mu.Lock()
+		delete(d.listeners, cookie)
+		d.mu.Unlock()
+		for i := 0; i < maxInFlight; i++ {
+			<-sema
+		}
+	}
+
+	// Process the pre-existing keys.
+	for _, k := range keys {
+		select {
+		case <-ctx.Done():
+			return stop
+		default:
+		}
+		if v, ok := d.Load(k); ok {
+			listener(v)
+		}
+	}
+
+	return stop
 }
 
 // Store stores the package info for dir.
 func (d *dirInfoCache) Store(dir string, info directoryPackageInfo) {
 	d.mu.Lock()
-	defer d.mu.Unlock()
-	stored := info // defensive copy
-	d.dirs[dir] = &stored
+	_, old := d.dirs[dir]
+	d.dirs[dir] = &info
+	var listeners []cacheListener
+	for _, l := range d.listeners {
+		listeners = append(listeners, l)
+	}
+	d.mu.Unlock()
+
+	if !old {
+		for _, l := range listeners {
+			l(info)
+		}
+	}
 }
 
 // Load returns a copy of the directoryPackageInfo for absolute directory dir.
@@ -129,17 +196,17 @@ func (d *dirInfoCache) Keys() (keys []string) {
 	return keys
 }
 
-func (d *dirInfoCache) CachePackageName(info directoryPackageInfo) (directoryPackageInfo, error) {
+func (d *dirInfoCache) CachePackageName(info directoryPackageInfo) (string, error) {
 	if loaded, err := info.reachedStatus(nameLoaded); loaded {
-		return info, err
+		return info.packageName, err
 	}
 	if scanned, err := info.reachedStatus(directoryScanned); !scanned || err != nil {
-		return info, fmt.Errorf("cannot read package name, scan error: %v", err)
+		return "", fmt.Errorf("cannot read package name, scan error: %v", err)
 	}
 	info.packageName, info.err = packageDirToName(info.dir)
 	info.status = nameLoaded
 	d.Store(info.dir, info)
-	return info, info.err
+	return info.packageName, info.err
 }
 
 func (d *dirInfoCache) CacheExports(ctx context.Context, env *ProcessEnv, info directoryPackageInfo) (string, []string, error) {
@@ -149,8 +216,8 @@ func (d *dirInfoCache) CacheExports(ctx context.Context, env *ProcessEnv, info d
 	if reached, err := info.reachedStatus(nameLoaded); reached && err != nil {
 		return "", nil, err
 	}
-	info.packageName, info.exports, info.err = loadExportsFromFiles(ctx, env, info.dir)
-	if info.err == context.Canceled {
+	info.packageName, info.exports, info.err = loadExportsFromFiles(ctx, env, info.dir, false)
+	if info.err == context.Canceled || info.err == context.DeadlineExceeded {
 		return info.packageName, info.exports, info.err
 	}
 	// The cache structure wants things to proceed linearly. We can skip a

vendor/golang.org/x/tools/internal/module/module.go

@@ -1,540 +0,0 @@
-// 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 module defines the module.Version type
-// along with support code.
-package module
-
-// IMPORTANT NOTE
-//
-// This file essentially defines the set of valid import paths for the go command.
-// There are many subtle considerations, including Unicode ambiguity,
-// security, network, and file system representations.
-//
-// This file also defines the set of valid module path and version combinations,
-// another topic with many subtle considerations.
-//
-// Changes to the semantics in this file require approval from rsc.
-
-import (
-	"fmt"
-	"sort"
-	"strings"
-	"unicode"
-	"unicode/utf8"
-
-	"golang.org/x/tools/internal/semver"
-)
-
-// A Version is defined by a module path and version pair.
-type Version struct {
-	Path string
-
-	// Version is usually a semantic version in canonical form.
-	// There are two exceptions to this general rule.
-	// First, the top-level target of a build has no specific version
-	// and uses Version = "".
-	// Second, during MVS calculations the version "none" is used
-	// to represent the decision to take no version of a given module.
-	Version string `json:",omitempty"`
-}
-
-// Check checks that a given module path, version pair is valid.
-// In addition to the path being a valid module path
-// and the version being a valid semantic version,
-// the two must correspond.
-// For example, the path "yaml/v2" only corresponds to
-// semantic versions beginning with "v2.".
-func Check(path, version string) error {
-	if err := CheckPath(path); err != nil {
-		return err
-	}
-	if !semver.IsValid(version) {
-		return fmt.Errorf("malformed semantic version %v", version)
-	}
-	_, pathMajor, _ := SplitPathVersion(path)
-	if !MatchPathMajor(version, pathMajor) {
-		if pathMajor == "" {
-			pathMajor = "v0 or v1"
-		}
-		if pathMajor[0] == '.' { // .v1
-			pathMajor = pathMajor[1:]
-		}
-		return fmt.Errorf("mismatched module path %v and version %v (want %v)", path, version, pathMajor)
-	}
-	return nil
-}
-
-// firstPathOK reports whether r can appear in the first element of a module path.
-// The first element of the path must be an LDH domain name, at least for now.
-// To avoid case ambiguity, the domain name must be entirely lower case.
-func firstPathOK(r rune) bool {
-	return r == '-' || r == '.' ||
-		'0' <= r && r <= '9' ||
-		'a' <= r && r <= 'z'
-}
-
-// pathOK reports whether r can appear in an import path element.
-// Paths can be ASCII letters, ASCII digits, and limited ASCII punctuation: + - . _ and ~.
-// This matches what "go get" has historically recognized in import paths.
-// TODO(rsc): We would like to allow Unicode letters, but that requires additional
-// care in the safe encoding (see note below).
-func pathOK(r rune) bool {
-	if r < utf8.RuneSelf {
-		return r == '+' || r == '-' || r == '.' || r == '_' || r == '~' ||
-			'0' <= r && r <= '9' ||
-			'A' <= r && r <= 'Z' ||
-			'a' <= r && r <= 'z'
-	}
-	return false
-}
-
-// fileNameOK reports whether r can appear in a file name.
-// For now we allow all Unicode letters but otherwise limit to pathOK plus a few more punctuation characters.
-// If we expand the set of allowed characters here, we have to
-// work harder at detecting potential case-folding and normalization collisions.
-// See note about "safe encoding" below.
-func fileNameOK(r rune) bool {
-	if r < utf8.RuneSelf {
-		// Entire set of ASCII punctuation, from which we remove characters:
-		//     ! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ \ ] ^ _ ` { | } ~
-		// We disallow some shell special characters: " ' * < > ? ` |
-		// (Note that some of those are disallowed by the Windows file system as well.)
-		// We also disallow path separators / : and \ (fileNameOK is only called on path element characters).
-		// We allow spaces (U+0020) in file names.
-		const allowed = "!#$%&()+,-.=@[]^_{}~ "
-		if '0' <= r && r <= '9' || 'A' <= r && r <= 'Z' || 'a' <= r && r <= 'z' {
-			return true
-		}
-		for i := 0; i < len(allowed); i++ {
-			if rune(allowed[i]) == r {
-				return true
-			}
-		}
-		return false
-	}
-	// It may be OK to add more ASCII punctuation here, but only carefully.
-	// For example Windows disallows < > \, and macOS disallows :, so we must not allow those.
-	return unicode.IsLetter(r)
-}
-
-// CheckPath checks that a module path is valid.
-func CheckPath(path string) error {
-	if err := checkPath(path, false); err != nil {
-		return fmt.Errorf("malformed module path %q: %v", path, err)
-	}
-	i := strings.Index(path, "/")
-	if i < 0 {
-		i = len(path)
-	}
-	if i == 0 {
-		return fmt.Errorf("malformed module path %q: leading slash", path)
-	}
-	if !strings.Contains(path[:i], ".") {
-		return fmt.Errorf("malformed module path %q: missing dot in first path element", path)
-	}
-	if path[0] == '-' {
-		return fmt.Errorf("malformed module path %q: leading dash in first path element", path)
-	}
-	for _, r := range path[:i] {
-		if !firstPathOK(r) {
-			return fmt.Errorf("malformed module path %q: invalid char %q in first path element", path, r)
-		}
-	}
-	if _, _, ok := SplitPathVersion(path); !ok {
-		return fmt.Errorf("malformed module path %q: invalid version", path)
-	}
-	return nil
-}
-
-// CheckImportPath checks that an import path is valid.
-func CheckImportPath(path string) error {
-	if err := checkPath(path, false); err != nil {
-		return fmt.Errorf("malformed import path %q: %v", path, err)
-	}
-	return nil
-}
-
-// checkPath checks that a general path is valid.
-// It returns an error describing why but not mentioning path.
-// Because these checks apply to both module paths and import paths,
-// the caller is expected to add the "malformed ___ path %q: " prefix.
-// fileName indicates whether the final element of the path is a file name
-// (as opposed to a directory name).
-func checkPath(path string, fileName bool) error {
-	if !utf8.ValidString(path) {
-		return fmt.Errorf("invalid UTF-8")
-	}
-	if path == "" {
-		return fmt.Errorf("empty string")
-	}
-	if strings.Contains(path, "..") {
-		return fmt.Errorf("double dot")
-	}
-	if strings.Contains(path, "//") {
-		return fmt.Errorf("double slash")
-	}
-	if path[len(path)-1] == '/' {
-		return fmt.Errorf("trailing slash")
-	}
-	elemStart := 0
-	for i, r := range path {
-		if r == '/' {
-			if err := checkElem(path[elemStart:i], fileName); err != nil {
-				return err
-			}
-			elemStart = i + 1
-		}
-	}
-	if err := checkElem(path[elemStart:], fileName); err != nil {
-		return err
-	}
-	return nil
-}
-
-// checkElem checks whether an individual path element is valid.
-// fileName indicates whether the element is a file name (not a directory name).
-func checkElem(elem string, fileName bool) error {
-	if elem == "" {
-		return fmt.Errorf("empty path element")
-	}
-	if strings.Count(elem, ".") == len(elem) {
-		return fmt.Errorf("invalid path element %q", elem)
-	}
-	if elem[0] == '.' && !fileName {
-		return fmt.Errorf("leading dot in path element")
-	}
-	if elem[len(elem)-1] == '.' {
-		return fmt.Errorf("trailing dot in path element")
-	}
-	charOK := pathOK
-	if fileName {
-		charOK = fileNameOK
-	}
-	for _, r := range elem {
-		if !charOK(r) {
-			return fmt.Errorf("invalid char %q", r)
-		}
-	}
-
-	// Windows disallows a bunch of path elements, sadly.
-	// See https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file
-	short := elem
-	if i := strings.Index(short, "."); i >= 0 {
-		short = short[:i]
-	}
-	for _, bad := range badWindowsNames {
-		if strings.EqualFold(bad, short) {
-			return fmt.Errorf("disallowed path element %q", elem)
-		}
-	}
-	return nil
-}
-
-// CheckFilePath checks whether a slash-separated file path is valid.
-func CheckFilePath(path string) error {
-	if err := checkPath(path, true); err != nil {
-		return fmt.Errorf("malformed file path %q: %v", path, err)
-	}
-	return nil
-}
-
-// badWindowsNames are the reserved file path elements on Windows.
-// See https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file
-var badWindowsNames = []string{
-	"CON",
-	"PRN",
-	"AUX",
-	"NUL",
-	"COM1",
-	"COM2",
-	"COM3",
-	"COM4",
-	"COM5",
-	"COM6",
-	"COM7",
-	"COM8",
-	"COM9",
-	"LPT1",
-	"LPT2",
-	"LPT3",
-	"LPT4",
-	"LPT5",
-	"LPT6",
-	"LPT7",
-	"LPT8",
-	"LPT9",
-}
-
-// SplitPathVersion returns prefix and major version such that prefix+pathMajor == path
-// and version is either empty or "/vN" for N >= 2.
-// As a special case, gopkg.in paths are recognized directly;
-// they require ".vN" instead of "/vN", and for all N, not just N >= 2.
-func SplitPathVersion(path string) (prefix, pathMajor string, ok bool) {
-	if strings.HasPrefix(path, "gopkg.in/") {
-		return splitGopkgIn(path)
-	}
-
-	i := len(path)
-	dot := false
-	for i > 0 && ('0' <= path[i-1] && path[i-1] <= '9' || path[i-1] == '.') {
-		if path[i-1] == '.' {
-			dot = true
-		}
-		i--
-	}
-	if i <= 1 || i == len(path) || path[i-1] != 'v' || path[i-2] != '/' {
-		return path, "", true
-	}
-	prefix, pathMajor = path[:i-2], path[i-2:]
-	if dot || len(pathMajor) <= 2 || pathMajor[2] == '0' || pathMajor == "/v1" {
-		return path, "", false
-	}
-	return prefix, pathMajor, true
-}
-
-// splitGopkgIn is like SplitPathVersion but only for gopkg.in paths.
-func splitGopkgIn(path string) (prefix, pathMajor string, ok bool) {
-	if !strings.HasPrefix(path, "gopkg.in/") {
-		return path, "", false
-	}
-	i := len(path)
-	if strings.HasSuffix(path, "-unstable") {
-		i -= len("-unstable")
-	}
-	for i > 0 && ('0' <= path[i-1] && path[i-1] <= '9') {
-		i--
-	}
-	if i <= 1 || path[i-1] != 'v' || path[i-2] != '.' {
-		// All gopkg.in paths must end in vN for some N.
-		return path, "", false
-	}
-	prefix, pathMajor = path[:i-2], path[i-2:]
-	if len(pathMajor) <= 2 || pathMajor[2] == '0' && pathMajor != ".v0" {
-		return path, "", false
-	}
-	return prefix, pathMajor, true
-}
-
-// MatchPathMajor reports whether the semantic version v
-// matches the path major version pathMajor.
-func MatchPathMajor(v, pathMajor string) bool {
-	if strings.HasPrefix(pathMajor, ".v") && strings.HasSuffix(pathMajor, "-unstable") {
-		pathMajor = strings.TrimSuffix(pathMajor, "-unstable")
-	}
-	if strings.HasPrefix(v, "v0.0.0-") && pathMajor == ".v1" {
-		// Allow old bug in pseudo-versions that generated v0.0.0- pseudoversion for gopkg .v1.
-		// For example, gopkg.in/yaml.v2@v2.2.1's go.mod requires gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405.
-		return true
-	}
-	m := semver.Major(v)
-	if pathMajor == "" {
-		return m == "v0" || m == "v1" || semver.Build(v) == "+incompatible"
-	}
-	return (pathMajor[0] == '/' || pathMajor[0] == '.') && m == pathMajor[1:]
-}
-
-// CanonicalVersion returns the canonical form of the version string v.
-// It is the same as semver.Canonical(v) except that it preserves the special build suffix "+incompatible".
-func CanonicalVersion(v string) string {
-	cv := semver.Canonical(v)
-	if semver.Build(v) == "+incompatible" {
-		cv += "+incompatible"
-	}
-	return cv
-}
-
-// Sort sorts the list by Path, breaking ties by comparing Versions.
-func Sort(list []Version) {
-	sort.Slice(list, func(i, j int) bool {
-		mi := list[i]
-		mj := list[j]
-		if mi.Path != mj.Path {
-			return mi.Path < mj.Path
-		}
-		// To help go.sum formatting, allow version/file.
-		// Compare semver prefix by semver rules,
-		// file by string order.
-		vi := mi.Version
-		vj := mj.Version
-		var fi, fj string
-		if k := strings.Index(vi, "/"); k >= 0 {
-			vi, fi = vi[:k], vi[k:]
-		}
-		if k := strings.Index(vj, "/"); k >= 0 {
-			vj, fj = vj[:k], vj[k:]
-		}
-		if vi != vj {
-			return semver.Compare(vi, vj) < 0
-		}
-		return fi < fj
-	})
-}
-
-// Safe encodings
-//
-// Module paths appear as substrings of file system paths
-// (in the download cache) and of web server URLs in the proxy protocol.
-// In general we cannot rely on file systems to be case-sensitive,
-// nor can we rely on web servers, since they read from file systems.
-// That is, we cannot rely on the file system to keep rsc.io/QUOTE
-// and rsc.io/quote separate. Windows and macOS don't.
-// Instead, we must never require two different casings of a file path.
-// Because we want the download cache to match the proxy protocol,
-// and because we want the proxy protocol to be possible to serve
-// from a tree of static files (which might be stored on a case-insensitive
-// file system), the proxy protocol must never require two different casings
-// of a URL path either.
-//
-// One possibility would be to make the safe encoding be the lowercase
-// hexadecimal encoding of the actual path bytes. This would avoid ever
-// needing different casings of a file path, but it would be fairly illegible
-// to most programmers when those paths appeared in the file system
-// (including in file paths in compiler errors and stack traces)
-// in web server logs, and so on. Instead, we want a safe encoding that
-// leaves most paths unaltered.
-//
-// The safe encoding is this:
-// replace every uppercase letter with an exclamation mark
-// followed by the letter's lowercase equivalent.
-//
-// For example,
-// github.com/Azure/azure-sdk-for-go ->  github.com/!azure/azure-sdk-for-go.
-// github.com/GoogleCloudPlatform/cloudsql-proxy -> github.com/!google!cloud!platform/cloudsql-proxy
-// github.com/Sirupsen/logrus -> github.com/!sirupsen/logrus.
-//
-// Import paths that avoid upper-case letters are left unchanged.
-// Note that because import paths are ASCII-only and avoid various
-// problematic punctuation (like : < and >), the safe encoding is also ASCII-only
-// and avoids the same problematic punctuation.
-//
-// Import paths have never allowed exclamation marks, so there is no
-// need to define how to encode a literal !.
-//
-// Although paths are disallowed from using Unicode (see pathOK above),
-// the eventual plan is to allow Unicode letters as well, to assume that
-// file systems and URLs are Unicode-safe (storing UTF-8), and apply
-// the !-for-uppercase convention. Note however that not all runes that
-// are different but case-fold equivalent are an upper/lower pair.
-// For example, U+004B ('K'), U+006B ('k'), and U+212A ('K' for Kelvin)
-// are considered to case-fold to each other. When we do add Unicode
-// letters, we must not assume that upper/lower are the only case-equivalent pairs.
-// Perhaps the Kelvin symbol would be disallowed entirely, for example.
-// Or perhaps it would encode as "!!k", or perhaps as "(212A)".
-//
-// Also, it would be nice to allow Unicode marks as well as letters,
-// but marks include combining marks, and then we must deal not
-// only with case folding but also normalization: both U+00E9 ('é')
-// and U+0065 U+0301 ('e' followed by combining acute accent)
-// look the same on the page and are treated by some file systems
-// as the same path. If we do allow Unicode marks in paths, there
-// must be some kind of normalization to allow only one canonical
-// encoding of any character used in an import path.
-
-// EncodePath returns the safe encoding of the given module path.
-// It fails if the module path is invalid.
-func EncodePath(path string) (encoding string, err error) {
-	if err := CheckPath(path); err != nil {
-		return "", err
-	}
-
-	return encodeString(path)
-}
-
-// EncodeVersion returns the safe encoding of the given module version.
-// Versions are allowed to be in non-semver form but must be valid file names
-// and not contain exclamation marks.
-func EncodeVersion(v string) (encoding string, err error) {
-	if err := checkElem(v, true); err != nil || strings.Contains(v, "!") {
-		return "", fmt.Errorf("disallowed version string %q", v)
-	}
-	return encodeString(v)
-}
-
-func encodeString(s string) (encoding string, err error) {
-	haveUpper := false
-	for _, r := range s {
-		if r == '!' || r >= utf8.RuneSelf {
-			// This should be disallowed by CheckPath, but diagnose anyway.
-			// The correctness of the encoding loop below depends on it.
-			return "", fmt.Errorf("internal error: inconsistency in EncodePath")
-		}
-		if 'A' <= r && r <= 'Z' {
-			haveUpper = true
-		}
-	}
-
-	if !haveUpper {
-		return s, nil
-	}
-
-	var buf []byte
-	for _, r := range s {
-		if 'A' <= r && r <= 'Z' {
-			buf = append(buf, '!', byte(r+'a'-'A'))
-		} else {
-			buf = append(buf, byte(r))
-		}
-	}
-	return string(buf), nil
-}
-
-// DecodePath returns the module path of the given safe encoding.
-// It fails if the encoding is invalid or encodes an invalid path.
-func DecodePath(encoding string) (path string, err error) {
-	path, ok := decodeString(encoding)
-	if !ok {
-		return "", fmt.Errorf("invalid module path encoding %q", encoding)
-	}
-	if err := CheckPath(path); err != nil {
-		return "", fmt.Errorf("invalid module path encoding %q: %v", encoding, err)
-	}
-	return path, nil
-}
-
-// DecodeVersion returns the version string for the given safe encoding.
-// It fails if the encoding is invalid or encodes an invalid version.
-// Versions are allowed to be in non-semver form but must be valid file names
-// and not contain exclamation marks.
-func DecodeVersion(encoding string) (v string, err error) {
-	v, ok := decodeString(encoding)
-	if !ok {
-		return "", fmt.Errorf("invalid version encoding %q", encoding)
-	}
-	if err := checkElem(v, true); err != nil {
-		return "", fmt.Errorf("disallowed version string %q", v)
-	}
-	return v, nil
-}
-
-func decodeString(encoding string) (string, bool) {
-	var buf []byte
-
-	bang := false
-	for _, r := range encoding {
-		if r >= utf8.RuneSelf {
-			return "", false
-		}
-		if bang {
-			bang = false
-			if r < 'a' || 'z' < r {
-				return "", false
-			}
-			buf = append(buf, byte(r+'A'-'a'))
-			continue
-		}
-		if r == '!' {
-			bang = true
-			continue
-		}
-		if 'A' <= r && r <= 'Z' {
-			return "", false
-		}
-		buf = append(buf, byte(r))
-	}
-	if bang {
-		return "", false
-	}
-	return string(buf), true
-}

vendor/golang.org/x/tools/internal/packagesinternal/packages.go

@@ -0,0 +1,27 @@
+// Package packagesinternal exposes internal-only fields from go/packages.
+package packagesinternal
+
+import "time"
+
+// Fields must match go list;
+type Module struct {
+	Path      string       // module path
+	Version   string       // module version
+	Versions  []string     // available module versions (with -versions)
+	Replace   *Module      // replaced by this module
+	Time      *time.Time   // time version was created
+	Update    *Module      // available update, if any (with -u)
+	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 used when loading this module, if any
+	GoVersion string       // go version used in module
+	Error     *ModuleError // error loading module
+}
+type ModuleError struct {
+	Err string // the error itself
+}
+
+var GetForTest = func(p interface{}) string { return "" }
+
+var GetModule = func(p interface{}) *Module { return nil }

vendor/golang.org/x/tools/internal/semver/semver.go

@@ -1,388 +0,0 @@
-// 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 implements comparison of semantic version strings.
-// In this package, semantic version strings must begin with a leading "v",
-// as in "v1.0.0".
-//
-// The general form of a semantic version string accepted by this package is
-//
-//	vMAJOR[.MINOR[.PATCH[-PRERELEASE][+BUILD]]]
-//
-// where square brackets indicate optional parts of the syntax;
-// MAJOR, MINOR, and PATCH are decimal integers without extra leading zeros;
-// PRERELEASE and BUILD are each a series of non-empty dot-separated identifiers
-// using only alphanumeric characters and hyphens; and
-// all-numeric PRERELEASE identifiers must not have leading zeros.
-//
-// This package follows Semantic Versioning 2.0.0 (see semver.org)
-// with two exceptions. First, it requires the "v" prefix. Second, it recognizes
-// vMAJOR and vMAJOR.MINOR (with no prerelease or build suffixes)
-// as shorthands for vMAJOR.0.0 and vMAJOR.MINOR.0.
-package semver
-
-// parsed returns the parsed form of a semantic version string.
-type parsed struct {
-	major      string
-	minor      string
-	patch      string
-	short      string
-	prerelease string
-	build      string
-	err        string
-}
-
-// IsValid reports whether v is a valid semantic version string.
-func IsValid(v string) bool {
-	_, ok := parse(v)
-	return ok
-}
-
-// Canonical returns the canonical formatting of the semantic version v.
-// It fills in any missing .MINOR or .PATCH and discards build metadata.
-// Two semantic versions compare equal only if their canonical formattings
-// are identical strings.
-// The canonical invalid semantic version is the empty string.
-func Canonical(v string) string {
-	p, ok := parse(v)
-	if !ok {
-		return ""
-	}
-	if p.build != "" {
-		return v[:len(v)-len(p.build)]
-	}
-	if p.short != "" {
-		return v + p.short
-	}
-	return v
-}
-
-// Major returns the major version prefix of the semantic version v.
-// For example, Major("v2.1.0") == "v2".
-// If v is an invalid semantic version string, Major returns the empty string.
-func Major(v string) string {
-	pv, ok := parse(v)
-	if !ok {
-		return ""
-	}
-	return v[:1+len(pv.major)]
-}
-
-// MajorMinor returns the major.minor version prefix of the semantic version v.
-// For example, MajorMinor("v2.1.0") == "v2.1".
-// If v is an invalid semantic version string, MajorMinor returns the empty string.
-func MajorMinor(v string) string {
-	pv, ok := parse(v)
-	if !ok {
-		return ""
-	}
-	i := 1 + len(pv.major)
-	if j := i + 1 + len(pv.minor); j <= len(v) && v[i] == '.' && v[i+1:j] == pv.minor {
-		return v[:j]
-	}
-	return v[:i] + "." + pv.minor
-}
-
-// Prerelease returns the prerelease suffix of the semantic version v.
-// For example, Prerelease("v2.1.0-pre+meta") == "-pre".
-// If v is an invalid semantic version string, Prerelease returns the empty string.
-func Prerelease(v string) string {
-	pv, ok := parse(v)
-	if !ok {
-		return ""
-	}
-	return pv.prerelease
-}
-
-// Build returns the build suffix of the semantic version v.
-// For example, Build("v2.1.0+meta") == "+meta".
-// If v is an invalid semantic version string, Build returns the empty string.
-func Build(v string) string {
-	pv, ok := parse(v)
-	if !ok {
-		return ""
-	}
-	return pv.build
-}
-
-// Compare returns an integer comparing two versions according to
-// according to semantic version precedence.
-// The result will be 0 if v == w, -1 if v < w, or +1 if v > w.
-//
-// An invalid semantic version string is considered less than a valid one.
-// All invalid semantic version strings compare equal to each other.
-func Compare(v, w string) int {
-	pv, ok1 := parse(v)
-	pw, ok2 := parse(w)
-	if !ok1 && !ok2 {
-		return 0
-	}
-	if !ok1 {
-		return -1
-	}
-	if !ok2 {
-		return +1
-	}
-	if c := compareInt(pv.major, pw.major); c != 0 {
-		return c
-	}
-	if c := compareInt(pv.minor, pw.minor); c != 0 {
-		return c
-	}
-	if c := compareInt(pv.patch, pw.patch); c != 0 {
-		return c
-	}
-	return comparePrerelease(pv.prerelease, pw.prerelease)
-}
-
-// Max canonicalizes its arguments and then returns the version string
-// that compares greater.
-func Max(v, w string) string {
-	v = Canonical(v)
-	w = Canonical(w)
-	if Compare(v, w) > 0 {
-		return v
-	}
-	return w
-}
-
-func parse(v string) (p parsed, ok bool) {
-	if v == "" || v[0] != 'v' {
-		p.err = "missing v prefix"
-		return
-	}
-	p.major, v, ok = parseInt(v[1:])
-	if !ok {
-		p.err = "bad major version"
-		return
-	}
-	if v == "" {
-		p.minor = "0"
-		p.patch = "0"
-		p.short = ".0.0"
-		return
-	}
-	if v[0] != '.' {
-		p.err = "bad minor prefix"
-		ok = false
-		return
-	}
-	p.minor, v, ok = parseInt(v[1:])
-	if !ok {
-		p.err = "bad minor version"
-		return
-	}
-	if v == "" {
-		p.patch = "0"
-		p.short = ".0"
-		return
-	}
-	if v[0] != '.' {
-		p.err = "bad patch prefix"
-		ok = false
-		return
-	}
-	p.patch, v, ok = parseInt(v[1:])
-	if !ok {
-		p.err = "bad patch version"
-		return
-	}
-	if len(v) > 0 && v[0] == '-' {
-		p.prerelease, v, ok = parsePrerelease(v)
-		if !ok {
-			p.err = "bad prerelease"
-			return
-		}
-	}
-	if len(v) > 0 && v[0] == '+' {
-		p.build, v, ok = parseBuild(v)
-		if !ok {
-			p.err = "bad build"
-			return
-		}
-	}
-	if v != "" {
-		p.err = "junk on end"
-		ok = false
-		return
-	}
-	ok = true
-	return
-}
-
-func parseInt(v string) (t, rest string, ok bool) {
-	if v == "" {
-		return
-	}
-	if v[0] < '0' || '9' < v[0] {
-		return
-	}
-	i := 1
-	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
-		i++
-	}
-	if v[0] == '0' && i != 1 {
-		return
-	}
-	return v[:i], v[i:], true
-}
-
-func parsePrerelease(v string) (t, rest string, ok bool) {
-	// "A pre-release version MAY be denoted by appending a hyphen and
-	// a series of dot separated identifiers immediately following the patch version.
-	// Identifiers MUST comprise only ASCII alphanumerics and hyphen [0-9A-Za-z-].
-	// Identifiers MUST NOT be empty. Numeric identifiers MUST NOT include leading zeroes."
-	if v == "" || v[0] != '-' {
-		return
-	}
-	i := 1
-	start := 1
-	for i < len(v) && v[i] != '+' {
-		if !isIdentChar(v[i]) && v[i] != '.' {
-			return
-		}
-		if v[i] == '.' {
-			if start == i || isBadNum(v[start:i]) {
-				return
-			}
-			start = i + 1
-		}
-		i++
-	}
-	if start == i || isBadNum(v[start:i]) {
-		return
-	}
-	return v[:i], v[i:], true
-}
-
-func parseBuild(v string) (t, rest string, ok bool) {
-	if v == "" || v[0] != '+' {
-		return
-	}
-	i := 1
-	start := 1
-	for i < len(v) {
-		if !isIdentChar(v[i]) {
-			return
-		}
-		if v[i] == '.' {
-			if start == i {
-				return
-			}
-			start = i + 1
-		}
-		i++
-	}
-	if start == i {
-		return
-	}
-	return v[:i], v[i:], true
-}
-
-func isIdentChar(c byte) bool {
-	return 'A' <= c && c <= 'Z' || 'a' <= c && c <= 'z' || '0' <= c && c <= '9' || c == '-'
-}
-
-func isBadNum(v string) bool {
-	i := 0
-	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
-		i++
-	}
-	return i == len(v) && i > 1 && v[0] == '0'
-}
-
-func isNum(v string) bool {
-	i := 0
-	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
-		i++
-	}
-	return i == len(v)
-}
-
-func compareInt(x, y string) int {
-	if x == y {
-		return 0
-	}
-	if len(x) < len(y) {
-		return -1
-	}
-	if len(x) > len(y) {
-		return +1
-	}
-	if x < y {
-		return -1
-	} else {
-		return +1
-	}
-}
-
-func comparePrerelease(x, y string) int {
-	// "When major, minor, and patch are equal, a pre-release version has
-	// lower precedence than a normal version.
-	// Example: 1.0.0-alpha < 1.0.0.
-	// Precedence for two pre-release versions with the same major, minor,
-	// and patch version MUST be determined by comparing each dot separated
-	// identifier from left to right until a difference is found as follows:
-	// identifiers consisting of only digits are compared numerically and
-	// identifiers with letters or hyphens are compared lexically in ASCII
-	// sort order. Numeric identifiers always have lower precedence than
-	// non-numeric identifiers. A larger set of pre-release fields has a
-	// higher precedence than a smaller set, if all of the preceding
-	// identifiers are equal.
-	// Example: 1.0.0-alpha < 1.0.0-alpha.1 < 1.0.0-alpha.beta <
-	// 1.0.0-beta < 1.0.0-beta.2 < 1.0.0-beta.11 < 1.0.0-rc.1 < 1.0.0."
-	if x == y {
-		return 0
-	}
-	if x == "" {
-		return +1
-	}
-	if y == "" {
-		return -1
-	}
-	for x != "" && y != "" {
-		x = x[1:] // skip - or .
-		y = y[1:] // skip - or .
-		var dx, dy string
-		dx, x = nextIdent(x)
-		dy, y = nextIdent(y)
-		if dx != dy {
-			ix := isNum(dx)
-			iy := isNum(dy)
-			if ix != iy {
-				if ix {
-					return -1
-				} else {
-					return +1
-				}
-			}
-			if ix {
-				if len(dx) < len(dy) {
-					return -1
-				}
-				if len(dx) > len(dy) {
-					return +1
-				}
-			}
-			if dx < dy {
-				return -1
-			} else {
-				return +1
-			}
-		}
-	}
-	if x == "" {
-		return -1
-	} else {
-		return +1
-	}
-}
-
-func nextIdent(x string) (dx, rest string) {
-	i := 0
-	for i < len(x) && x[i] != '.' {
-		i++
-	}
-	return x[:i], x[i:]
-}