code review 5586044: reflect: add comment about Type.Field allocation

reflect: add comment about Type.Field allocation

[rsc, 2012-01-27 16:51:10]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://go.googlecode.com/hg/

[bradfitz, 2012-01-27 16:57:07]

LGTM

On Fri, Jan 27, 2012 at 8:51 AM, <rsc@golang.org> wrote:

> Reviewers: golang-dev_googlegroups.com,
>
> Message:
> Hello golang-dev@googlegroups.com,
>
> I'd like you to review this change to
> https://go.googlecode.com/hg/
>
>
> Description:
> reflect: add comment about Type.Field allocation
>
> Please review this at
http://codereview.appspot.com/**5586044/<http://codereview.appspot.com/5586044/>
>
> Affected files:
>  M src/pkg/reflect/type.go
>
>
> Index: src/pkg/reflect/type.go
> ==============================**==============================**=======
> --- a/src/pkg/reflect/type.go
> +++ b/src/pkg/reflect/type.go
> @@ -789,6 +789,14 @@
>                f.Tag = StructTag(*p.tag)
>        }
>        f.Offset = p.offset
> +
> +       // NOTE(rsc): This is the only allocation in the interface
> +       // presented by a reflect.Type.  It would be nice to avoid,
> +       // at least in the common cases, but we need to make sure
> +       // that misbehaving clients of reflect cannot affect other
> +       // uses of reflect.  One possibility is CL 5371098, but we
> +       // postponed that ugliness until there is a demonstrated
> +       // need for the performance.  This is issue 2320.
>        f.Index = []int{i}
>        return
>  }
>
>
>

[r, 2012-01-27 17:09:48]

LGTM

[rsc, 2012-01-27 21:11:22]

*** Submitted as http://code.google.com/p/go/source/detail?r=bd9dd41f80e2 ***

reflect: add comment about Type.Field allocation

R=golang-dev, bradfitz, r
CC=golang-dev
http://codereview.appspot.com/5586044