From 0fd270ab7abec08c050f29a3bbeb83d7740d0a47 Mon Sep 17 00:00:00 2001 From: Andrew Gerrand Date: Fri, 8 Apr 2016 15:39:32 +1000 Subject: text/template: emit field error over nil pointer error where appropriate When evaluating "{{.MissingField}}" on a nil *T, Exec returns "can't evaluate field MissingField in type *T" instead of "nil pointer evaluating *T.MissingField". Fixes golang/go#15125 Change-Id: I6e73f61b8a72c694179c1f8cdc808766c90b6f57 Reviewed-on: https://go-review.googlesource.com/21705 Reviewed-by: Rob Pike --- src/text/template/exec.go | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'src/text/template/exec.go') diff --git a/src/text/template/exec.go b/src/text/template/exec.go index a169e62ab0..22881c6852 100644 --- a/src/text/template/exec.go +++ b/src/text/template/exec.go @@ -538,14 +538,14 @@ func (s *state) evalField(dot reflect.Value, fieldName string, node parse.Node, return s.evalCall(dot, method, node, fieldName, args, final) } hasArgs := len(args) > 1 || final.IsValid() - // It's not a method; must be a field of a struct or an element of a map. The receiver must not be nil. - if isNil { - s.errorf("nil pointer evaluating %s.%s", typ, fieldName) - } + // It's not a method; must be a field of a struct or an element of a map. switch receiver.Kind() { case reflect.Struct: tField, ok := receiver.Type().FieldByName(fieldName) if ok { + if isNil { + s.errorf("nil pointer evaluating %s.%s", typ, fieldName) + } field := receiver.FieldByIndex(tField.Index) if tField.PkgPath != "" { // field is unexported s.errorf("%s is an unexported field of struct type %s", fieldName, typ) @@ -556,8 +556,10 @@ func (s *state) evalField(dot reflect.Value, fieldName string, node parse.Node, } return field } - s.errorf("%s is not a field of struct type %s", fieldName, typ) case reflect.Map: + if isNil { + s.errorf("nil pointer evaluating %s.%s", typ, fieldName) + } // If it's a map, attempt to use the field name as a key. nameVal := reflect.ValueOf(fieldName) if nameVal.Type().AssignableTo(receiver.Type().Key()) { -- cgit v1.3