code review 7100050: net: introduce noncgo_net build tag to disable cgo only...

net: introduce netgo build tag to build a pure Go net package.
Fixes issue 4078.

[bradfitz, 2013-06-04 21:58:36]

R=rsc

... since he filed Issue 4078.

[minux1, 2013-06-07 09:36:37]

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

I'd like you to review this change to
https://code.google.com/p/go

[iant, 2013-06-07 13:36:22]

I don't understand what will set this build tag.  Negated names are always hard
to understand, especially when the main use of them is with the ! operator.  Is
it possible to use cgo_net rather than noncgo_net?

It should probably be cgonet, actually, with no underscore.

[minux1, 2013-06-07 14:00:50]

On 2013/06/07 13:36:22, iant wrote:
> I don't understand what will set this build tag.  Negated names are always
hard
> to understand, especially when the main use of them is with the ! operator. 
Is
> it possible to use cgo_net rather than noncgo_net?
yes, but we will have to somehow enable the tag cgo_net by default.
> It should probably be cgonet, actually, with no underscore.
yeah, i like cgonet better, but we need to figure out whether
we want to make cgonet the default.
i can see multiple problems here, for example, what if the user
actually use a tag called cgonet in his own source? should we hardcode
the build tag just for the net package?

with noncgo_net, the name is not good, but it's there for people
who want something unusual (and he just need to install net once
with this tag, so the tag won't affect his own source).

[iant, 2013-06-07 14:30:52]

On 2013/06/07 14:00:50, minux wrote:

> yeah, i like cgonet better, but we need to figure out whether
> we want to make cgonet the default.
> i can see multiple problems here, for example, what if the user
> actually use a tag called cgonet in his own source? should we hardcode
> the build tag just for the net package?

We already have a builtin tag "cgo", I don't see adding "cgonet" as a big
problem.

I don't know when to set it, though.

Ian

[rsc, 2013-06-10 17:48:55]

The negative is precisely because we can't introduce a new tag that's always on.
We can only allow people to specify a new tag to add to the set. We can't use
'cgonet' because cgonet is not part of the default set, and if it were there'd
be no way to remove it.

Using a better name with the same semantics would help though. Perhaps 'netgo'
to mean 'net in pure go'.

[minux1, 2013-06-10 17:55:33]

PTAL, changed to use netgo, and updated doc/go1.2.txt.

On 2013/06/10 17:48:55, rsc wrote:
> Using a better name with the same semantics would help though. Perhaps 'netgo'
> to mean 'net in pure go'.

[iant, 2013-06-10 18:06:41]

Update the CL description.

[minux1, 2013-06-10 18:11:38]

On 2013/06/10 18:06:41, iant wrote:
> Update the CL description.
thank you, done.

[iant, 2013-06-10 18:13:06]

LGTM

Wait for rsc.

[rsc, 2013-06-10 18:51:16]

LGTM

[minux1, 2013-06-10 18:55:25]

*** Submitted as https://code.google.com/p/go/source/detail?r=17822bec6f33 ***

net: introduce netgo build tag to build a pure Go net package.
Fixes issue 4078.

R=golang-dev, bradfitz, rsc, iant
CC=golang-dev
https://codereview.appspot.com/7100050