diff --git a/src/pkg/text/template/exec.go b/src/pkg/text/template/exec.go index 0c633e6bab..5fad5ccecb 100644 --- a/src/pkg/text/template/exec.go +++ b/src/pkg/text/template/exec.go @@ -520,6 +520,13 @@ func (s *state) validateType(value reflect.Value, typ reflect.Type) reflect.Valu } } if !value.Type().AssignableTo(typ) { + if value.Kind() == reflect.Interface && !value.IsNil() { + value = value.Elem() + if value.Type().AssignableTo(typ) { + return value + } + // fallthrough + } // Does one dereference or indirection work? We could do more, as we // do with method receivers, but that gets messy and method receivers // are much more constrained, so it makes more sense there than here. diff --git a/src/pkg/text/template/exec_test.go b/src/pkg/text/template/exec_test.go index 8f6c67bbaa..c8a3013977 100644 --- a/src/pkg/text/template/exec_test.go +++ b/src/pkg/text/template/exec_test.go @@ -314,6 +314,7 @@ var execTests = []execTest{ {".VariadicFuncInt", "{{call .VariadicFuncInt 33 `he` `llo`}}", "33=", tVal, true}, {"if .BinaryFunc call", "{{ if .BinaryFunc}}{{call .BinaryFunc `1` `2`}}{{end}}", "[1=2]", tVal, true}, {"if not .BinaryFunc call", "{{ if not .BinaryFunc}}{{call .BinaryFunc `1` `2`}}{{else}}No{{end}}", "No", tVal, true}, + {"Interface Call", `{{stringer .S}}`, "foozle", map[string]interface{}{"S": bytes.NewBufferString("foozle")}, true}, // Erroneous function calls (check args). {".BinaryFuncTooFew", "{{call .BinaryFunc `1`}}", "", tVal, false}, @@ -512,6 +513,10 @@ func vfunc(V, *V) string { return "vfunc" } +func stringer(s fmt.Stringer) string { + return s.String() +} + func testExecute(execTests []execTest, template *Template, t *testing.T) { b := new(bytes.Buffer) funcs := FuncMap{ @@ -521,6 +526,7 @@ func testExecute(execTests []execTest, template *Template, t *testing.T) { "typeOf": typeOf, "vfunc": vfunc, "zeroArgs": zeroArgs, + "stringer": stringer, } for _, test := range execTests { var tmpl *Template