libgo: update to go1.7rc3

    
    Reviewed-on: https://go-review.googlesource.com/25150


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@238662 138bc75d-0d04-0410-961f-82ee72b054a4

2 files changed, 26 insertions, 6 deletions

diff --git a/libgo/go/expvar/expvar.go b/libgo/go/expvar/expvar.go
index 24c2d6b29ab..d5465c518f8 100644
--- a/libgo/go/expvar/expvar.go
+++ b/libgo/go/expvar/expvar.go
@@ -15,7 +15,7 @@
 //	memstats  runtime.Memstats
 //
 // The package is sometimes only imported for the side effect of
-// registering its HTTP handler and the above variables.  To use it
+// registering its HTTP handler and the above variables. To use it
 // this way, link this package into your program:
 //	import _ "expvar"
 //
@@ -38,6 +38,9 @@ import (
 
 // Var is an abstract type for all exported variables.
 type Var interface {
+	// String returns a valid JSON value for the variable.
+	// Types with String methods that do not return valid JSON
+	// (such as time.Time) must not be used as a Var.
 	String() string
 }
 
@@ -218,8 +221,10 @@ type String struct {
 
 func (v *String) String() string {
 	v.mu.RLock()
-	defer v.mu.RUnlock()
-	return strconv.Quote(v.s)
+	s := v.s
+	v.mu.RUnlock()
+	b, _ := json.Marshal(s)
+	return string(b)
 }
 
 func (v *String) Set(value string) {
@@ -258,7 +263,8 @@ func Publish(name string, v Var) {
 	sort.Strings(varKeys)
 }
 
-// Get retrieves a named exported variable.
+// Get retrieves a named exported variable. It returns nil if the name has
+// not been registered.
 func Get(name string) Var {
 	mutex.RLock()
 	defer mutex.RUnlock()
diff --git a/libgo/go/expvar/expvar_test.go b/libgo/go/expvar/expvar_test.go
index 8bc633e4a97..7b1c9dfc4f8 100644
--- a/libgo/go/expvar/expvar_test.go
+++ b/libgo/go/expvar/expvar_test.go
@@ -26,6 +26,14 @@ func RemoveAll() {
 	varKeys = nil
 }
 
+func TestNil(t *testing.T) {
+	RemoveAll()
+	val := Get("missing")
+	if val != nil {
+		t.Errorf("got %v, want nil", val)
+	}
+}
+
 func TestInt(t *testing.T) {
 	RemoveAll()
 	reqs := NewInt("requests")
@@ -134,8 +142,14 @@ func TestString(t *testing.T) {
 		t.Errorf("name.s = %q, want \"Mike\"", name.s)
 	}
 
-	if s := name.String(); s != "\"Mike\"" {
-		t.Errorf("reqs.String() = %q, want \"\"Mike\"\"", s)
+	if s, want := name.String(), `"Mike"`; s != want {
+		t.Errorf("from %q, name.String() = %q, want %q", name.s, s, want)
+	}
+
+	// Make sure we produce safe JSON output.
+	name.Set(`<`)
+	if s, want := name.String(), "\"\\u003c\""; s != want {
+		t.Errorf("from %q, name.String() = %q, want %q", name.s, s, want)
 	}
 }