code review 91240045: io: document MultiReader and MultiWriter owning the slices

io: document MultiReader and MultiWriter owning the slices

Fixes Issue 7809

[bradfitz, 2014-05-07 19:16:14]

Hello golang-codereviews@googlegroups.com (cc: iant@golang.org, r@golang.org),

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

[iant, 2014-05-07 19:41:41]

https://codereview.appspot.com/91240045/diff/30001/src/pkg/io/multi.go
File src/pkg/io/multi.go (right):

https://codereview.appspot.com/91240045/diff/30001/src/pkg/io/multi.go#newcode32
src/pkg/io/multi.go:32: // The caller should not modify the provided readers
slice while the
I think this is a little confusing because the vast majority of callers will not
be providing a slice.  Perhaps something more like this?

If called with a slice as in MultiReader(s...), the caller should not modify the
provided slice while the returned Reader is in use.

[bradfitz, 2014-05-07 19:44:43]

Hello golang-codereviews@googlegroups.com, iant@golang.org (cc:
golang-codereviews@googlegroups.com, r@golang.org),

Please take another look.

[bradfitz, 2014-05-07 19:45:23]

Done.

Yeah, this is tricky to describe, since we don't have good terminology for
this and it doesn't happen often.

PTAL



On Wed, May 7, 2014 at 12:41 PM, <iant@golang.org> wrote:

>
> https://codereview.appspot.com/91240045/diff/30001/src/pkg/io/multi.go
> File src/pkg/io/multi.go (right):
>
> https://codereview.appspot.com/91240045/diff/30001/src/
> pkg/io/multi.go#newcode32
> src/pkg/io/multi.go:32: // The caller should not modify the provided
> readers slice while the
> I think this is a little confusing because the vast majority of callers
> will not be providing a slice.  Perhaps something more like this?
>
> If called with a slice as in MultiReader(s...), the caller should not
> modify the provided slice while the returned Reader is in use.
>
> https://codereview.appspot.com/91240045/
>

[iant, 2014-05-07 20:49:09]

LGTM

Might want to see what r thinks.

[adg, 2014-05-08 03:58:05]

I'm not sure about the precedent.
Do we need to add the same comments to, say, fmt.Printf?

[bradfitz, 2014-05-08 04:49:34]

There are no lifetime issues with fmt.

Lifetimes are documented elsewhere in our docs.
 On May 7, 2014 8:58 PM, <adg@golang.org> wrote:

> I'm not sure about the precedent.
> Do we need to add the same comments to, say, fmt.Printf?
>
>
> https://codereview.appspot.com/91240045/
>

[adg, 2014-05-08 05:04:06]

On 8 May 2014 14:49, Brad Fitzpatrick <bradfitz@golang.org> wrote:

> There are no lifetime issues with fmt.
>
> Lifetimes are documented elsewhere in our docs.
>

Oh yeah, I missed that important distinction.

[rsc, 2014-05-09 18:34:11]

I think doing a doc fix is a mistake. Why not make a real slice copy?

[rsc, 2014-05-13 02:25:49]

On 2014/05/09 18:34:11, rsc wrote:
> I think doing a doc fix is a mistake. Why not make a real slice copy?

CL 94380043 does the explicit copy.