go/packages/golist.go - tools - Git at Google

 // 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 packages

 import (
 	"bytes"
 	"encoding/json"
 	"fmt"
 	"log"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"strings"
 )

 // A goTooOldError reports that the go command
 // found by exec.LookPath is too old to use the new go list behavior.
 type goTooOldError struct {
 	error
 }

 // goListDriver uses the go list command to interpret the patterns and produce
 // the build system package structure.
 // See driver for more details.
 func goListDriver(cfg *Config, patterns ...string) (*driverResponse, error) {
 	// Determine files requested in contains patterns
 	var containFiles []string
 	restPatterns := make([]string, 0, len(patterns))
 	for _, pattern := range patterns {
 		if strings.HasPrefix(pattern, "contains:") {
 			containFile := strings.TrimPrefix(pattern, "contains:")
 			containFiles = append(containFiles, containFile)
 		} else {
 			restPatterns = append(restPatterns, pattern)
 		}
 	}
 	containFiles = absJoin(cfg.Dir, containFiles)
 	patterns = restPatterns

 	// TODO(matloob): Remove the definition of listfunc and just use golistPackages once go1.12 is released.
 	var listfunc driver
 	listfunc = func(cfg *Config, words ...string) (*driverResponse, error) {
 		response, err := golistDriverCurrent(cfg, patterns...)
 		if _, ok := err.(goTooOldError); ok {
 			listfunc = golistDriverFallback
 			return listfunc(cfg, patterns...)
 		}
 		listfunc = golistDriverCurrent
 		return response, err
 	}

 	var response *driverResponse
 	var err error

 	// see if we have any patterns to pass through to go list.
 	if len(patterns) > 0 {
 		response, err = listfunc(cfg, patterns...)
 		if err != nil {
 			return nil, err
 		}
 	} else {
 		response = &driverResponse{}
 	}

 	// Run go list for contains: patterns.
 	seenPkgs := make(map[string]*Package) // for deduplication. different containing queries could produce same packages
 	if len(containFiles) > 0 {
 		for _, pkg := range response.Packages {
 			seenPkgs[pkg.ID] = pkg
 		}
 	}
 	for _, f := range containFiles {
 		// TODO(matloob): Do only one query per directory.
 		fdir := filepath.Dir(f)
 		cfg.Dir = fdir
 		dirResponse, err := listfunc(cfg, ".")
 		if err != nil {
 			return nil, err
 		}
 		isRoot := make(map[string]bool, len(dirResponse.Roots))
 		for _, root := range dirResponse.Roots {
 			isRoot[root] = true
 		}
 		for _, pkg := range dirResponse.Packages {
 			// Add any new packages to the main set
 			// We don't bother to filter packages that will be dropped by the changes of roots,
 			// that will happen anyway during graph construction outside this function.
 			// Over-reporting packages is not a problem.
 			if _, ok := seenPkgs[pkg.ID]; !ok {
 				// it is a new package, just add it
 				seenPkgs[pkg.ID] = pkg
 				response.Packages = append(response.Packages, pkg)
 			}
 			// if the package was not a root one, it cannot have the file
 			if !isRoot[pkg.ID] {
 				continue
 			}
 			for _, pkgFile := range pkg.GoFiles {
 				if filepath.Base(f) == filepath.Base(pkgFile) {
 					response.Roots = append(response.Roots, pkg.ID)
 					break
 				}
 			}
 		}
 	}
 	return response, nil
 }

 // Fields must match go list;
 // see $GOROOT/src/cmd/go/internal/load/pkg.go.
 type jsonPackage struct {
 	ImportPath      string
 	Dir             string
 	Name            string
 	Export          string
 	GoFiles         []string
 	CompiledGoFiles []string
 	CFiles          []string
 	CgoFiles        []string
 	CXXFiles        []string
 	MFiles          []string
 	HFiles          []string
 	FFiles          []string
 	SFiles          []string
 	SwigFiles       []string
 	SwigCXXFiles    []string
 	SysoFiles       []string
 	Imports         []string
 	ImportMap       map[string]string
 	Deps            []string
 	TestGoFiles     []string
 	TestImports     []string
 	XTestGoFiles    []string
 	XTestImports    []string
 	ForTest         string // q in a "p [q.test]" package, else ""
 	DepOnly         bool
 }

 func otherFiles(p *jsonPackage) [][]string {
 	return [][]string{p.CFiles, p.CXXFiles, p.MFiles, p.HFiles, p.FFiles, p.SFiles, p.SwigFiles, p.SwigCXXFiles, p.SysoFiles}
 }

 // golistDriverCurrent uses the "go list" command to expand the
 // pattern words and return metadata for the specified packages.
 // dir may be "" and env may be nil, as per os/exec.Command.
 func golistDriverCurrent(cfg *Config, words ...string) (*driverResponse, error) {
 	// go list uses the following identifiers in ImportPath and Imports:
 	//
 	// 	"p"			-- importable package or main (command)
 	//      "q.test"		-- q's test executable
 	// 	"p [q.test]"		-- variant of p as built for q's test executable
 	//	"q_test [q.test]"	-- q's external test package
 	//
 	// The packages p that are built differently for a test q.test
 	// are q itself, plus any helpers used by the external test q_test,
 	// typically including "testing" and all its dependencies.

 	// Run "go list" for complete
 	// information on the specified packages.
 	buf, err := golist(cfg, golistargs(cfg, words))
 	if err != nil {
 		return nil, err
 	}
 	// Decode the JSON and convert it to Package form.
 	var response driverResponse
 	for dec := json.NewDecoder(buf); dec.More(); {
 		p := new(jsonPackage)
 		if err := dec.Decode(p); err != nil {
 			return nil, fmt.Errorf("JSON decoding failed: %v", err)
 		}

 		// Bad package?
 		if p.Name == "" {
 			// This could be due to:
 			// - no such package
 			// - package directory contains no Go source files
 			// - all package declarations are mangled
 			// - and possibly other things.
 			//
 			// For now, we throw it away and let later
 			// stages rediscover the problem, but this
 			// discards the error message computed by go list
 			// and computes a new one---by different logic:
 			// if only one of the package declarations is
 			// bad, for example, should we report an error
 			// in Metadata mode?
 			// Unless we parse and typecheck, we might not
 			// notice there's a problem.
 			//
 			// Perhaps we should save a map of PackageID to
 			// errors for such cases.
 			continue
 		}

 		id := p.ImportPath

 		// Extract the PkgPath from the package's ID.
 		pkgpath := id
 		if i := strings.IndexByte(id, ' '); i >= 0 {
 			pkgpath = id[:i]
 		}

 		if pkgpath == "unsafe" {
 			p.GoFiles = nil // ignore fake unsafe.go file
 		}

 		// Assume go list emits only absolute paths for Dir.
 		if !filepath.IsAbs(p.Dir) {
 			log.Fatalf("internal error: go list returned non-absolute Package.Dir: %s", p.Dir)
 		}

 		export := p.Export
 		if export != "" && !filepath.IsAbs(export) {
 			export = filepath.Join(p.Dir, export)
 		}

 		// imports
 		//
 		// Imports contains the IDs of all imported packages.
 		// ImportsMap records (path, ID) only where they differ.
 		ids := make(map[string]bool)
 		for _, id := range p.Imports {
 			ids[id] = true
 		}
 		imports := make(map[string]*Package)
 		for path, id := range p.ImportMap {
 			imports[path] = &Package{ID: id} // non-identity import
 			delete(ids, id)
 		}
 		for id := range ids {
 			if id == "C" {
 				continue
 			}

 			imports[id] = &Package{ID: id} // identity import
 		}
 		if !p.DepOnly {
 			response.Roots = append(response.Roots, id)
 		}
 		pkg := &Package{
 			ID:              id,
 			Name:            p.Name,
 			PkgPath:         pkgpath,
 			GoFiles:         absJoin(p.Dir, p.GoFiles, p.CgoFiles),
 			CompiledGoFiles: absJoin(p.Dir, p.CompiledGoFiles),
 			OtherFiles:      absJoin(p.Dir, otherFiles(p)...),
 			Imports:         imports,
 			ExportFile:      export,
 		}
 		// TODO(matloob): Temporary hack since CompiledGoFiles isn't always set.
 		if len(pkg.CompiledGoFiles) == 0 {
 			pkg.CompiledGoFiles = pkg.GoFiles
 		}
 		response.Packages = append(response.Packages, pkg)
 	}

 	return &response, nil
 }

 // absJoin absolutizes and flattens the lists of files.
 func absJoin(dir string, fileses ...[]string) (res []string) {
 	for _, files := range fileses {
 		for _, file := range files {
 			if !filepath.IsAbs(file) {
 				file = filepath.Join(dir, file)
 			}
 			res = append(res, file)
 		}
 	}
 	return res
 }

 func golistargs(cfg *Config, words []string) []string {
 	fullargs := []string{
 		"list", "-e", "-json", "-compiled",
 		fmt.Sprintf("-test=%t", cfg.Tests),
 		fmt.Sprintf("-export=%t", usesExportData(cfg)),
 		fmt.Sprintf("-deps=%t", cfg.Mode >= LoadImports),
 	}
 	fullargs = append(fullargs, cfg.Flags...)
 	fullargs = append(fullargs, "--")
 	fullargs = append(fullargs, words...)
 	return fullargs
 }

 // golist returns the JSON-encoded result of a "go list args..." query.
 func golist(cfg *Config, args []string) (*bytes.Buffer, error) {
 	out := new(bytes.Buffer)
 	cmd := exec.CommandContext(cfg.Context, "go", args...)
 	cmd.Env = cfg.Env
 	cmd.Dir = cfg.Dir
 	cmd.Stdout = out
 	cmd.Stderr = new(bytes.Buffer)
 	if err := cmd.Run(); err != nil {
 		exitErr, ok := err.(*exec.ExitError)
 		if !ok {
 			// Catastrophic error:
 			// - executable not found
 			// - context cancellation
 			return nil, fmt.Errorf("couldn't exec 'go list': %s %T", err, err)
 		}

 		// Old go list?
 		if strings.Contains(fmt.Sprint(cmd.Stderr), "flag provided but not defined") {
 			return nil, goTooOldError{fmt.Errorf("unsupported version of go list: %s: %s", exitErr, cmd.Stderr)}
 		}

 		// Export mode entails a build.
 		// If that build fails, errors appear on stderr
 		// (despite the -e flag) and the Export field is blank.
 		// Do not fail in that case.
 		if !usesExportData(cfg) {
 			return nil, fmt.Errorf("go list: %s: %s", exitErr, cmd.Stderr)
 		}
 	}

 	// Print standard error output from "go list".
 	// Due to the -e flag, this should be empty.
 	// However, in -export mode it contains build errors.
 	// Should go list save build errors in the Package.Error JSON field?
 	// See https://github.com/golang/go/issues/26319.
 	// If so, then we should continue to print stderr as go list
 	// will be silent unless something unexpected happened.
 	// If not, perhaps we should suppress it to reduce noise.
 	if stderr := fmt.Sprint(cmd.Stderr); stderr != "" {
 		fmt.Fprintf(os.Stderr, "go list stderr <<%s>>\n", stderr)
 	}

 	// debugging
 	if false {
 		fmt.Fprintln(os.Stderr, out)
 	}

 	return out, nil
 }
	// 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 packages

	import (
	"bytes"
	"encoding/json"
	"fmt"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	)

	// A goTooOldError reports that the go command
	// found by exec.LookPath is too old to use the new go list behavior.
	type goTooOldError struct {
	error
	}

	// goListDriver uses the go list command to interpret the patterns and produce
	// the build system package structure.
	// See driver for more details.
	func goListDriver(cfg Config, patterns ...string) (driverResponse, error) {
	// Determine files requested in contains patterns
	var containFiles []string
	restPatterns := make([]string, 0, len(patterns))
	for _, pattern := range patterns {
	if strings.HasPrefix(pattern, "contains:") {
	containFile := strings.TrimPrefix(pattern, "contains:")
	containFiles = append(containFiles, containFile)
	} else {
	restPatterns = append(restPatterns, pattern)
	}
	}
	containFiles = absJoin(cfg.Dir, containFiles)
	patterns = restPatterns

	// TODO(matloob): Remove the definition of listfunc and just use golistPackages once go1.12 is released.
	var listfunc driver
	listfunc = func(cfg Config, words ...string) (driverResponse, error) {
	response, err := golistDriverCurrent(cfg, patterns...)
	if _, ok := err.(goTooOldError); ok {
	listfunc = golistDriverFallback
	return listfunc(cfg, patterns...)
	}
	listfunc = golistDriverCurrent
	return response, err
	}

	var response *driverResponse
	var err error

	// see if we have any patterns to pass through to go list.
	if len(patterns) > 0 {
	response, err = listfunc(cfg, patterns...)
	if err != nil {
	return nil, err
	}
	} else {
	response = &driverResponse{}
	}

	// Run go list for contains: patterns.
	seenPkgs := make(map[string]*Package) // for deduplication. different containing queries could produce same packages
	if len(containFiles) > 0 {
	for _, pkg := range response.Packages {
	seenPkgs[pkg.ID] = pkg
	}
	}
	for _, f := range containFiles {
	// TODO(matloob): Do only one query per directory.
	fdir := filepath.Dir(f)
	cfg.Dir = fdir
	dirResponse, err := listfunc(cfg, ".")
	if err != nil {
	return nil, err
	}
	isRoot := make(map[string]bool, len(dirResponse.Roots))
	for _, root := range dirResponse.Roots {
	isRoot[root] = true
	}
	for _, pkg := range dirResponse.Packages {
	// Add any new packages to the main set
	// We don't bother to filter packages that will be dropped by the changes of roots,
	// that will happen anyway during graph construction outside this function.
	// Over-reporting packages is not a problem.
	if _, ok := seenPkgs[pkg.ID]; !ok {
	// it is a new package, just add it
	seenPkgs[pkg.ID] = pkg
	response.Packages = append(response.Packages, pkg)
	}
	// if the package was not a root one, it cannot have the file
	if !isRoot[pkg.ID] {
	continue
	}
	for _, pkgFile := range pkg.GoFiles {
	if filepath.Base(f) == filepath.Base(pkgFile) {
	response.Roots = append(response.Roots, pkg.ID)
	break
	}
	}
	}
	}
	return response, nil
	}

	// Fields must match go list;
	// see $GOROOT/src/cmd/go/internal/load/pkg.go.
	type jsonPackage struct {
	ImportPath string
	Dir string
	Name string
	Export string
	GoFiles []string
	CompiledGoFiles []string
	CFiles []string
	CgoFiles []string
	CXXFiles []string
	MFiles []string
	HFiles []string
	FFiles []string
	SFiles []string
	SwigFiles []string
	SwigCXXFiles []string
	SysoFiles []string
	Imports []string
	ImportMap map[string]string
	Deps []string
	TestGoFiles []string
	TestImports []string
	XTestGoFiles []string
	XTestImports []string
	ForTest string // q in a "p [q.test]" package, else ""
	DepOnly bool
	}

	func otherFiles(p *jsonPackage) [][]string {
	return [][]string{p.CFiles, p.CXXFiles, p.MFiles, p.HFiles, p.FFiles, p.SFiles, p.SwigFiles, p.SwigCXXFiles, p.SysoFiles}
	}

	// golistDriverCurrent uses the "go list" command to expand the
	// pattern words and return metadata for the specified packages.
	// dir may be "" and env may be nil, as per os/exec.Command.
	func golistDriverCurrent(cfg Config, words ...string) (driverResponse, error) {
	// go list uses the following identifiers in ImportPath and Imports:
	//
	// "p" -- importable package or main (command)
	// "q.test" -- q's test executable
	// "p [q.test]" -- variant of p as built for q's test executable
	// "q_test [q.test]" -- q's external test package
	//
	// The packages p that are built differently for a test q.test
	// are q itself, plus any helpers used by the external test q_test,
	// typically including "testing" and all its dependencies.

	// Run "go list" for complete
	// information on the specified packages.
	buf, err := golist(cfg, golistargs(cfg, words))
	if err != nil {
	return nil, err
	}
	// Decode the JSON and convert it to Package form.
	var response driverResponse
	for dec := json.NewDecoder(buf); dec.More(); {
	p := new(jsonPackage)
	if err := dec.Decode(p); err != nil {
	return nil, fmt.Errorf("JSON decoding failed: %v", err)
	}

	// Bad package?
	if p.Name == "" {
	// This could be due to:
	// - no such package
	// - package directory contains no Go source files
	// - all package declarations are mangled
	// - and possibly other things.
	//
	// For now, we throw it away and let later
	// stages rediscover the problem, but this
	// discards the error message computed by go list
	// and computes a new one---by different logic:
	// if only one of the package declarations is
	// bad, for example, should we report an error
	// in Metadata mode?
	// Unless we parse and typecheck, we might not
	// notice there's a problem.
	//
	// Perhaps we should save a map of PackageID to
	// errors for such cases.
	continue
	}

	id := p.ImportPath

	// Extract the PkgPath from the package's ID.
	pkgpath := id
	if i := strings.IndexByte(id, ' '); i >= 0 {
	pkgpath = id[:i]
	}

	if pkgpath == "unsafe" {
	p.GoFiles = nil // ignore fake unsafe.go file
	}

	// Assume go list emits only absolute paths for Dir.
	if !filepath.IsAbs(p.Dir) {
	log.Fatalf("internal error: go list returned non-absolute Package.Dir: %s", p.Dir)
	}

	export := p.Export
	if export != "" && !filepath.IsAbs(export) {
	export = filepath.Join(p.Dir, export)
	}

	// imports
	//
	// Imports contains the IDs of all imported packages.
	// ImportsMap records (path, ID) only where they differ.
	ids := make(map[string]bool)
	for _, id := range p.Imports {
	ids[id] = true
	}
	imports := make(map[string]*Package)
	for path, id := range p.ImportMap {
	imports[path] = &Package{ID: id} // non-identity import
	delete(ids, id)
	}
	for id := range ids {
	if id == "C" {
	continue
	}

	imports[id] = &Package{ID: id} // identity import
	}
	if !p.DepOnly {
	response.Roots = append(response.Roots, id)
	}
	pkg := &Package{
	ID: id,
	Name: p.Name,
	PkgPath: pkgpath,
	GoFiles: absJoin(p.Dir, p.GoFiles, p.CgoFiles),
	CompiledGoFiles: absJoin(p.Dir, p.CompiledGoFiles),
	OtherFiles: absJoin(p.Dir, otherFiles(p)...),
	Imports: imports,
	ExportFile: export,
	}
	// TODO(matloob): Temporary hack since CompiledGoFiles isn't always set.
	if len(pkg.CompiledGoFiles) == 0 {
	pkg.CompiledGoFiles = pkg.GoFiles
	}
	response.Packages = append(response.Packages, pkg)
	}

	return &response, nil
	}

	// absJoin absolutizes and flattens the lists of files.
	func absJoin(dir string, fileses ...[]string) (res []string) {
	for _, files := range fileses {
	for _, file := range files {
	if !filepath.IsAbs(file) {
	file = filepath.Join(dir, file)
	}
	res = append(res, file)
	}
	}
	return res
	}

	func golistargs(cfg *Config, words []string) []string {
	fullargs := []string{
	"list", "-e", "-json", "-compiled",
	fmt.Sprintf("-test=%t", cfg.Tests),
	fmt.Sprintf("-export=%t", usesExportData(cfg)),
	fmt.Sprintf("-deps=%t", cfg.Mode >= LoadImports),
	}
	fullargs = append(fullargs, cfg.Flags...)
	fullargs = append(fullargs, "--")
	fullargs = append(fullargs, words...)
	return fullargs
	}

	// golist returns the JSON-encoded result of a "go list args..." query.
	func golist(cfg Config, args []string) (bytes.Buffer, error) {
	out := new(bytes.Buffer)
	cmd := exec.CommandContext(cfg.Context, "go", args...)
	cmd.Env = cfg.Env
	cmd.Dir = cfg.Dir
	cmd.Stdout = out
	cmd.Stderr = new(bytes.Buffer)
	if err := cmd.Run(); err != nil {
	exitErr, ok := err.(*exec.ExitError)
	if !ok {
	// Catastrophic error:
	// - executable not found
	// - context cancellation
	return nil, fmt.Errorf("couldn't exec 'go list': %s %T", err, err)
	}

	// Old go list?
	if strings.Contains(fmt.Sprint(cmd.Stderr), "flag provided but not defined") {
	return nil, goTooOldError{fmt.Errorf("unsupported version of go list: %s: %s", exitErr, cmd.Stderr)}
	}

	// Export mode entails a build.
	// If that build fails, errors appear on stderr
	// (despite the -e flag) and the Export field is blank.
	// Do not fail in that case.
	if !usesExportData(cfg) {
	return nil, fmt.Errorf("go list: %s: %s", exitErr, cmd.Stderr)
	}
	}

	// Print standard error output from "go list".
	// Due to the -e flag, this should be empty.
	// However, in -export mode it contains build errors.
	// Should go list save build errors in the Package.Error JSON field?
	// See https://github.com/golang/go/issues/26319.
	// If so, then we should continue to print stderr as go list
	// will be silent unless something unexpected happened.
	// If not, perhaps we should suppress it to reduce noise.
	if stderr := fmt.Sprint(cmd.Stderr); stderr != "" {
	fmt.Fprintf(os.Stderr, "go list stderr <<%s>>\n", stderr)
	}

	// debugging
	if false {
	fmt.Fprintln(os.Stderr, out)
	}

	return out, nil
	}