diff --git a/src/pkg/exp/template/exec.go b/src/pkg/exp/template/exec.go index 169c8c69183..4ec738f0dfd 100644 --- a/src/pkg/exp/template/exec.go +++ b/src/pkg/exp/template/exec.go @@ -589,12 +589,16 @@ func (s *state) evalEmptyInterface(dot reflect.Value, n node) reflect.Value { } // indirect returns the item at the end of indirection, and a bool to indicate if it's nil. +// We indirect through pointers and empty interfaces (only) because +// non-empty interfaces have methods we might need. func indirect(v reflect.Value) (rv reflect.Value, isNil bool) { - for v.Kind() == reflect.Ptr { + for v.Kind() == reflect.Ptr || v.Kind() == reflect.Interface { if v.IsNil() { return v, true } - v = v.Elem() + if v.Kind() == reflect.Ptr || v.NumMethod() == 0 { + v = v.Elem() + } } return v, false } diff --git a/src/pkg/exp/template/exec_test.go b/src/pkg/exp/template/exec_test.go index efac443668e..eb5ab71187a 100644 --- a/src/pkg/exp/template/exec_test.go +++ b/src/pkg/exp/template/exec_test.go @@ -69,7 +69,7 @@ var tVal = &T{ Empty1: 3, Empty2: "empty2", Empty3: []int{7, 8}, - Empty4: &U{"v"}, + Empty4: &U{"UinEmpty"}, PI: newInt(23), PSI: newIntSlice(21, 22, 23), Tmpl: New("x").MustParse("test template"), // "x" is the value of .X @@ -210,7 +210,8 @@ var execTests = []execTest{ {"empty with int", "{{.Empty1}}", "3", tVal, true}, {"empty with string", "{{.Empty2}}", "empty2", tVal, true}, {"empty with slice", "{{.Empty3}}", "[7 8]", tVal, true}, - {"empty with struct", "{{.Empty4}}", "{v}", tVal, true}, + {"empty with struct", "{{.Empty4}}", "{UinEmpty}", tVal, true}, + {"empty with struct, field", "{{.Empty4.V}}", "UinEmpty", tVal, true}, // Method calls. {".Method0", "-{{.Method0}}-", "-M0-", tVal, true}, @@ -308,7 +309,7 @@ var execTests = []execTest{ {"with slice", "{{with .SI}}{{.}}{{else}}EMPTY{{end}}", "[3 4 5]", tVal, true}, {"with emptymap", "{{with .MSIEmpty}}{{.}}{{else}}EMPTY{{end}}", "EMPTY", tVal, true}, {"with map", "{{with .MSIone}}{{.}}{{else}}EMPTY{{end}}", "map[one:1]", tVal, true}, - {"with empty interface, struct field", "{{with .Empty4}}{{.V}}{{end}}", "v", tVal, true}, + {"with empty interface, struct field", "{{with .Empty4}}{{.V}}{{end}}", "UinEmpty", tVal, true}, {"with $x int", "{{with $x := .I}}{{$x}}{{end}}", "17", tVal, true}, {"with $x struct.U.V", "{{with $x := $}}{{$x.U.V}}{{end}}", "v", tVal, true}, {"with variable and action", "{{with $x := $}}{{$y := $.U.V}},{{$y}}{{end}}", "v,v", tVal, true},