2 files changed, 26 insertions, 4 deletions
diff --git a/src/cmd/api/goapi.go b/src/cmd/api/goapi.go
index 01b17b8839..6a80ed269b 100644
--- a/src/cmd/api/goapi.go
+++ b/src/cmd/api/goapi.go
@@ -87,7 +87,10 @@ var contexts = []*build.Context{
 func contextName(c *build.Context) string {
 	s := c.GOOS + "-" + c.GOARCH
 	if c.CgoEnabled {
-		return s + "-cgo"
+		s += "-cgo"
+	}
+	if c.Dir != "" {
+		s += fmt.Sprintf(" [%s]", c.Dir)
 	}
 	return s
 }
@@ -478,6 +481,9 @@ func (w *Walker) loadImports() {
 
 		cmd := exec.Command(goCmd(), "list", "-e", "-deps", "-json", "std")
 		cmd.Env = listEnv(w.context)
+		if w.context.Dir != "" {
+			cmd.Dir = w.context.Dir
+		}
 		out, err := cmd.CombinedOutput()
 		if err != nil {
 			log.Fatalf("loading imports: %v\n%s", err, out)
@@ -491,6 +497,7 @@ func (w *Walker) loadImports() {
 			var pkg struct {
 				ImportPath, Dir string
 				ImportMap       map[string]string
+				Standard        bool
 			}
 			err := dec.Decode(&pkg)
 			if err == io.EOF {
@@ -503,11 +510,13 @@ func (w *Walker) loadImports() {
 			// - Package "unsafe" contains special signatures requiring
 			//   extra care when printing them - ignore since it is not
 			//   going to change w/o a language change.
-			// - internal and vendored packages do not contribute to our
-			//   API surface.
+			// - Internal and vendored packages do not contribute to our
+			//   API surface. (If we are running within the "std" module,
+			//   vendored dependencies appear as themselves instead of
+			//   their "vendor/" standard-library copies.)
 			// - 'go list std' does not include commands, which cannot be
 			//   imported anyway.
-			if ip := pkg.ImportPath; ip != "unsafe" && !strings.HasPrefix(ip, "vendor/") && !internalPkg.MatchString(ip) {
+			if ip := pkg.ImportPath; pkg.Standard && ip != "unsafe" && !strings.HasPrefix(ip, "vendor/") && !internalPkg.MatchString(ip) {
 				stdPackages = append(stdPackages, ip)
 			}
 			importDir[pkg.ImportPath] = pkg.Dir
diff --git a/src/cmd/api/goapi_test.go b/src/cmd/api/goapi_test.go
index eaccc5ceb5..24620a94af 100644
--- a/src/cmd/api/goapi_test.go
+++ b/src/cmd/api/goapi_test.go
@@ -216,3 +216,16 @@ func TestIssue29837(t *testing.T) {
 		}
 	}
 }
+
+func TestIssue41358(t *testing.T) {
+	context := new(build.Context)
+	*context = build.Default
+	context.Dir = filepath.Join(context.GOROOT, "src")
+
+	w := NewWalker(context, context.Dir)
+	for _, pkg := range w.stdPackages {
+		if strings.HasPrefix(pkg, "vendor/") || strings.HasPrefix(pkg, "golang.org/x/") {
+			t.Fatalf("stdPackages contains unexpected package %s", pkg)
+		}
+	}
+}