code review 6206106: net/http: clarify ErrBodyNotAllowed error message

net/http: clarify ErrBodyNotAllowed error message

It's usually due to writing on HEAD requests.

[bradfitz, 2012-05-23 15:58:16]

Hello golang-dev@googlegroups.com (cc: golang-dev@googlegroups.com),

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

[rsc, 2012-05-23 16:06:44]

"http: body not allowed" ?

[bradfitz, 2012-05-23 16:09:33]

Even shorter would be "bad", which is also not helpful in diagnosing the
problem.

If you can suggest something both short and helpful, I'm all ears.

On Wed, May 23, 2012 at 8:59 AM, Russ Cox <rsc@golang.org> wrote:

> "http: body not allowed" ?
>

[r2, 2012-05-23 16:19:31]

On May 23, 2012, at 9:09 AM, Brad Fitzpatrick wrote:

> Even shorter would be "bad", which is also not helpful in diagnosing the
problem.
> 
> If you can suggest something both short and helpful, I'm all ears.
> 
> On Wed, May 23, 2012 at 8:59 AM, Russ Cox <rsc@golang.org> wrote:
> "http: body not allowed" ?
> 

EPERM is shorter than "Permission denied", which is shorter than a proper error
message with good context, like "cannot open /tmp/precious: Permission denied".

What makes good error messages is the context more than the message itself. With
good context, "http: body not allowed" is enough. If you can't give context, the
proposed replacement is probably better. If you have context and the original,
the message will be logorrheic.

-rob

[bradfitz, 2012-05-23 16:25:54]

On Wed, May 23, 2012 at 9:19 AM, Rob 'Commander' Pike <r@google.com> wrote:

>
> On May 23, 2012, at 9:09 AM, Brad Fitzpatrick wrote:
>
> Even shorter would be "bad", which is also not helpful in diagnosing the
> problem.
>
> If you can suggest something both short and helpful, I'm all ears.
>
> On Wed, May 23, 2012 at 8:59 AM, Russ Cox <rsc@golang.org> wrote:
>
>> "http: body not allowed" ?
>>
>
>
> EPERM is shorter than "Permission denied", which is shorter than a proper
> error message with good context, like "cannot open /tmp/precious:
> Permission denied".
>
> What makes good error messages is the context more than the message
> itself. With good context, "http: body not allowed" is enough. If you can't
> give context, the proposed replacement is probably better. If you have
> context and the original, the message will be logorrheic.
>

I have context but can't return it without breaking Go1 compatibility.
 ErrBodyNotAllowed is part of the API and what we normally return.  I can't
start returning a new type.

[r, 2012-05-23 16:28:43]

> I have context but can't return it without breaking Go1 compatibility.
>  ErrBodyNotAllowed is part of the API and what we normally return.  I can't
> start returning a new type.

In the example I gave it wasn't the lowest level that provides the
context, but in Go we're trying to push good error reporting further
down where the context is known. Executive decision: This bike shed
will be painted with your colors.

-rob

[r, 2012-05-23 16:29:11]

LGTM

[bradfitz, 2012-05-23 16:31:32]

*** Submitted as http://code.google.com/p/go/source/detail?r=fe8549b7050a ***

net/http: clarify ErrBodyNotAllowed error message

It's usually due to writing on HEAD requests.

R=golang-dev, rsc, r, r
CC=golang-dev
http://codereview.appspot.com/6206106