4 files changed, 28 insertions, 32 deletions
diff --git a/src/cmd/api/goapi.go b/src/cmd/api/goapi.go
index ee0f92328e..fe9c862f4f 100644
--- a/src/cmd/api/goapi.go
+++ b/src/cmd/api/goapi.go
@@ -74,16 +74,10 @@ func main() {
 		pkgs = strings.Fields(string(stds))
 	}
 
-	tree, _, err := build.FindTree("os") // some known package
-	if err != nil {
-		log.Fatalf("failed to find tree: %v", err)
-	}
-
 	var featureCtx = make(map[string]map[string]bool) // feature -> context name -> true
 	for _, context := range contexts {
 		w := NewWalker()
 		w.context = context
-		w.tree = tree
 
 		for _, pkg := range pkgs {
 			w.wantedPkg[pkg] = true
@@ -95,7 +89,7 @@ func main() {
 				strings.HasPrefix(pkg, "old/") {
 				continue
 			}
-			if !tree.HasSrc(pkg) {
+			if fi, err := os.Stat(filepath.Join(w.root, pkg)); err != nil || !fi.IsDir() {
 				log.Fatalf("no source in tree for package %q", pkg)
 			}
 			w.WalkPackage(pkg)
@@ -165,7 +159,7 @@ type pkgSymbol struct {
 
 type Walker struct {
 	context         *build.Context
-	tree            *build.Tree
+	root            string
 	fset            *token.FileSet
 	scope           []string
 	features        map[string]bool // set
@@ -191,6 +185,7 @@ func NewWalker() *Walker {
 		selectorFullPkg: make(map[string]string),
 		wantedPkg:       make(map[string]bool),
 		prevConstType:   make(map[pkgSymbol]string),
+		root:            filepath.Join(build.Default.GOROOT, "src/pkg"),
 	}
 }
 
@@ -252,15 +247,13 @@ func (w *Walker) WalkPackage(name string) {
 	defer func() {
 		w.packageState[name] = loaded
 	}()
-	dir := filepath.Join(w.tree.SrcDir(), filepath.FromSlash(name))
+	dir := filepath.Join(w.root, filepath.FromSlash(name))
 
-	var info *build.DirInfo
-	var err error
-	if ctx := w.context; ctx != nil {
-		info, err = ctx.ScanDir(dir)
-	} else {
-		info, err = build.ScanDir(dir)
+	ctxt := w.context
+	if ctxt == nil {
+		ctxt = &build.Default
 	}
+	info, err := ctxt.ImportDir(dir, 0)
 	if err != nil {
 		if strings.Contains(err.Error(), "no Go source files") {
 			return
diff --git a/src/cmd/api/goapi_test.go b/src/cmd/api/goapi_test.go
index dbbec46b0d..c7cc601b1a 100644
--- a/src/cmd/api/goapi_test.go
+++ b/src/cmd/api/goapi_test.go
@@ -7,7 +7,6 @@ package main
 import (
 	"flag"
 	"fmt"
-	"go/build"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -36,7 +35,7 @@ func TestGolden(t *testing.T) {
 		w := NewWalker()
 		w.wantedPkg[fi.Name()] = true
 
-		w.tree = &build.Tree{Path: "testdata", Goroot: true}
+		w.root = "testdata/src/pkg"
 		goldenFile := filepath.Join("testdata", "src", "pkg", fi.Name(), "golden.txt")
 		w.WalkPackage(fi.Name())
 
diff --git a/src/cmd/godoc/godoc.go b/src/cmd/godoc/godoc.go
index 1f212a0bcd..e5f7a73d4f 100644
--- a/src/cmd/godoc/godoc.go
+++ b/src/cmd/godoc/godoc.go
@@ -15,6 +15,7 @@ import (
 	"go/printer"
 	"go/token"
 	"io"
+	"io/ioutil"
 	"log"
 	"net/http"
 	"net/url"
@@ -90,11 +91,11 @@ var (
 
 func initHandlers() {
 	paths := filepath.SplitList(*pkgPath)
-	for _, t := range build.Path {
-		if t.Goroot {
-			continue
+	gorootSrc := filepath.Join(build.Default.GOROOT, "src", "pkg")
+	for _, p := range build.Default.SrcDirs() {
+		if p != gorootSrc {
+			paths = append(paths, p)
 		}
-		paths = append(paths, t.SrcDir())
 	}
 	fsMap.Init(paths)
 
@@ -1002,11 +1003,13 @@ func fsReadDir(dir string) ([]os.FileInfo, error) {
 	return fs.ReadDir(dir)
 }
 
-// fsReadFile implements ReadFile for the go/build package.
-func fsReadFile(dir, name string) (path string, data []byte, err error) {
-	path = filepath.Join(dir, name)
-	data, err = ReadFile(fs, path)
-	return
+// fsOpenFile implements OpenFile for the go/build package.
+func fsOpenFile(name string) (r io.ReadCloser, err error) {
+	data, err := ReadFile(fs, name)
+	if err != nil {
+		return nil, err
+	}
+	return ioutil.NopCloser(bytes.NewReader(data)), nil
 }
 
 func inList(name string, list []string) bool {
@@ -1039,10 +1042,11 @@ func (h *httpHandler) getPageInfo(abspath, relpath, pkgname string, mode PageInf
 		// To use different pair, such as if we allowed the user
 		// to choose, set ctxt.GOOS and ctxt.GOARCH before
 		// calling ctxt.ScanDir.
-		ctxt := build.DefaultContext
+		ctxt := build.Default
+		ctxt.IsAbsPath = path.IsAbs
 		ctxt.ReadDir = fsReadDir
-		ctxt.ReadFile = fsReadFile
-		dir, err := ctxt.ScanDir(abspath)
+		ctxt.OpenFile = fsOpenFile
+		dir, err := ctxt.ImportDir(abspath, 0)
 		if err == nil {
 			pkgFiles = append(dir.GoFiles, dir.CgoFiles...)
 		}
diff --git a/src/cmd/godoc/main.go b/src/cmd/godoc/main.go
index ee905bb7a0..5f42105393 100644
--- a/src/cmd/godoc/main.go
+++ b/src/cmd/godoc/main.go
@@ -388,9 +388,9 @@ func main() {
 	}
 	relpath := path
 	abspath := path
-	if t, pkg, err := build.FindTree(path); err == nil {
-		relpath = pkg
-		abspath = filepath.Join(t.SrcDir(), pkg)
+	if bp, _ := build.Import(path, "", build.FindOnly); bp.Dir != "" && bp.ImportPath != "" {
+		relpath = bp.ImportPath
+		abspath = bp.Dir
 	} else if !filepath.IsAbs(path) {
 		abspath = absolutePath(path, pkgHandler.fsRoot)
 	} else {