1 files changed, 28 insertions, 6 deletions
diff --git a/libgo/go/html/template/template.go b/libgo/go/html/template/template.go
index b0bae7a54fb..edac7335cfd 100644
--- a/libgo/go/html/template/template.go
+++ b/libgo/go/html/template/template.go
@@ -31,6 +31,20 @@ type nameSpace struct {
 	set map[string]*Template
 }
 
+// Templates returns a slice of the templates associated with t, including t
+// itself.
+func (t *Template) Templates() []*Template {
+	ns := t.nameSpace
+	ns.mu.Lock()
+	defer ns.mu.Unlock()
+	// Return a slice so we don't expose the map.
+	m := make([]*Template, 0, len(ns.set))
+	for _, v := range ns.set {
+		m = append(m, v)
+	}
+	return m
+}
+
 // Execute applies a parsed template to the specified data object,
 // writing the output to wr.
 func (t *Template) Execute(wr io.Writer, data interface{}) (err error) {
@@ -64,7 +78,13 @@ func (t *Template) lookupAndEscapeTemplate(name string) (tmpl *Template, err err
 	t.nameSpace.mu.Lock()
 	defer t.nameSpace.mu.Unlock()
 	tmpl = t.set[name]
-	if (tmpl == nil) != (t.text.Lookup(name) == nil) {
+	if tmpl == nil {
+		return nil, fmt.Errorf("html/template: %q is undefined", name)
+	}
+	if tmpl.text.Tree == nil || tmpl.text.Root == nil {
+		return nil, fmt.Errorf("html/template: %q is an incomplete template", name)
+	}
+	if t.text.Lookup(name) == nil {
 		panic("html/template internal error: template escaping out of sync")
 	}
 	if tmpl != nil && !tmpl.escaped {
@@ -160,9 +180,11 @@ func (t *Template) Clone() (*Template, error) {
 		if src == nil || src.escaped {
 			return nil, fmt.Errorf("html/template: cannot Clone %q after it has executed", t.Name())
 		}
-		x.Tree = &parse.Tree{
-			Name: x.Tree.Name,
-			Root: x.Tree.Root.CopyList(),
+		if x.Tree != nil {
+			x.Tree = &parse.Tree{
+				Name: x.Tree.Name,
+				Root: x.Tree.Root.CopyList(),
+			}
 		}
 		ret.set[name] = &Template{
 			false,
@@ -274,7 +296,7 @@ func (t *Template) ParseFiles(filenames ...string) (*Template, error) {
 func parseFiles(t *Template, filenames ...string) (*Template, error) {
 	if len(filenames) == 0 {
 		// Not really a problem, but be consistent.
-		return nil, fmt.Errorf("template: no files named in call to ParseFiles")
+		return nil, fmt.Errorf("html/template: no files named in call to ParseFiles")
 	}
 	for _, filename := range filenames {
 		b, err := ioutil.ReadFile(filename)
@@ -331,7 +353,7 @@ func parseGlob(t *Template, pattern string) (*Template, error) {
 		return nil, err
 	}
 	if len(filenames) == 0 {
-		return nil, fmt.Errorf("template: pattern matches no files: %#q", pattern)
+		return nil, fmt.Errorf("html/template: pattern matches no files: %#q", pattern)
 	}
 	return parseFiles(t, filenames...)
 }