text/template: make redefinition of a template in a set more consistent.
Also make it agree with the documentation. You get an error, unless you're
calling Add explicitly, in which case it panics since that's almost certainly
a bug. The discrepancy was caused by a panic that wasn't turned into
an error along one path; deleted the offending function for clarity.
R=r, rsc
CC=golang-dev
https://golang.org/cl/5354045
diff --git a/src/pkg/text/template/parse.go b/src/pkg/text/template/parse.go
index 2fbd37f..6ecd2f5 100644
--- a/src/pkg/text/template/parse.go
+++ b/src/pkg/text/template/parse.go
@@ -71,7 +71,7 @@
// ParseInSet parses the template definition string to construct an internal
// representation of the template for execution. It also adds the template
-// to the set.
+// to the set. It is an error if s is already defined in the set.
// Function bindings are checked against those in the set.
func (t *Template) ParseInSet(s string, set *Set) (tmpl *Template, err error) {
var setFuncs FuncMap
@@ -82,15 +82,8 @@
if err != nil {
return nil, err
}
- t.addToSet(set)
- return t, nil
-}
-
-// addToSet adds the template to the set, verifying it's not being double-assigned.
-func (t *Template) addToSet(set *Set) {
- if set == nil || t.set == set {
- return
+ if set != nil {
+ err = set.add(t)
}
- // If double-assigned, Add will panic and we will turn that into an error.
- set.Add(t)
+ return t, err
}
diff --git a/src/pkg/text/template/set.go b/src/pkg/text/template/set.go
index bd0dfc6..ba5dc00 100644
--- a/src/pkg/text/template/set.go
+++ b/src/pkg/text/template/set.go
@@ -101,8 +101,7 @@
// Parse parses a string into a set of named templates. Parse may be called
// multiple times for a given set, adding the templates defined in the string
-// to the set. If a template is redefined, the element in the set is
-// overwritten with the new definition.
+// to the set. It is an error if a template has a name already defined in the set.
func (s *Set) Parse(text string) (*Set, error) {
trees, err := parse.Set(text, s.leftDelim, s.rightDelim, s.parseFuncs, builtins)
if err != nil {
@@ -112,8 +111,10 @@
for name, tree := range trees {
tmpl := New(name)
tmpl.Tree = tree
- tmpl.addToSet(s)
- s.tmpl[name] = tmpl
+ err = s.add(tmpl)
+ if err != nil {
+ return s, err
+ }
}
return s, nil
}
