code review 4897043: build: support versioning without hg

build: support versioning without hg

CL 4873048 introduced the ability to build without hg and
getting an "unknown" version.  While this approach works
to avoid the hg dependency, it also means that every
exported tree that is built without hg or .hg will have not
only missing information, but will also be compatible to
one another.  Considering that it is a common practice to
remove the VCS data in distributions, I suggest we don't
take this approach to avoid its consequences.

This CL fixes the same problem in a different way: if a
VERSION file at the top of the tree exists, use it at
all times.  If it doesn't, fall back to using information
from hg necessarily, and fail if that's not possible.  The
error message when VERSION and hg are not available
instructs users to handle it properly.

The VERSION file can be generated with
"src/version.bash -save" while hg is still around.

[niemeyer, 2011-08-15 16:18:28]

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, 2011-08-15 16:30:13]

if we're going to have VERSION,
it should override everything.

if it exists, don't bother with hg at all.

russ

[niemeyer, 2011-08-15 17:08:00]

> if we're going to have VERSION,
> it should override everything.

That's done. PTAL

[rsc, 2011-08-15 17:13:35]

LGTM

[rsc, 2011-08-15 17:13:41]

http://codereview.appspot.com/4897043/diff/13001/src/version.bash
File src/version.bash (right):

http://codereview.appspot.com/4897043/diff/13001/src/version.bash#newcode6
src/version.bash:6: GOROOT=$(cd `dirname $0`/..; pwd)
GOROOT="$(dirname $0)/.."
should suffice

[gustavo_niemeyer.net, 2011-08-15 17:17:39]

> GOROOT="$(dirname $0)/.."
> should suffice

It does, but the message on -save is slightly nicer with the current version.

-- 
Gustavo Niemeyer
http://niemeyer.net
http://niemeyer.net/plus
http://niemeyer.net/twitter
http://niemeyer.net/blog

-- I never filed a patent.

[niemeyer, 2011-08-15 17:19:38]

*** Submitted as http://code.google.com/p/go/source/detail?r=ed3e04904ee7 ***

build: support versioning without hg

CL 4873048 introduced the ability to build without hg and
getting an "unknown" version.  While this approach works
to avoid the hg dependency, it also means that every
exported tree that is built without hg or .hg will have not
only missing information, but will also be compatible to
one another.  Considering that it is a common practice to
remove the VCS data in distributions, I suggest we don't
take this approach to avoid its consequences.

This CL fixes the same problem in a different way: if a
VERSION file at the top of the tree exists, use it at
all times.  If it doesn't, fall back to using information
from hg necessarily, and fail if that's not possible.  The
error message when VERSION and hg are not available
instructs users to handle it properly.

The VERSION file can be generated with
"src/version.bash -save" while hg is still around.

R=golang-dev, rsc, gustavo
CC=golang-dev
http://codereview.appspot.com/4897043

[rsc, 2011-08-15 17:20:08]

> It does, but the message on -save is slightly nicer with the current version.

i missed that.  please delete that message.
programs that succeed should not print things.

[adg, 2011-08-15 21:51:28]

LGTM

Nice.

[lucio, 2011-08-18 06:54:43]

I had occasion to convert this BASH script to Plan 9's RC and I would
like to point out the following:

1. The -save option is not effective if a VERSION file already exists:
the code exits before testing.

2. I don't properly understand this, so I can't be sure that I can
improve it :-)

# Get branch type
BRANCH=release
if [ "$(hg identify -b 2>/dev/null)" == "default" ]; then
	BRANCH=weekly
fi

My translation:

BRANCH=`hg identify -b`
case $BRANCH in
  default) BRANCH=weekly;;
  "") BRANCH=release;;
esac

may not be quite what you want, but your version seems to ignore any
version other than "default" which doesn't seem right either.  I may
of course be missing something, feel free to put me right.

Lucio.

On 8/15/11, n13m3y3r@gmail.com <n13m3y3r@gmail.com> wrote:
> *** Submitted as
> http://code.google.com/p/go/source/detail?r=ed3e04904ee7 ***
>
> build: support versioning without hg
>
> CL 4873048 introduced the ability to build without hg and
> getting an "unknown" version.  While this approach works
> to avoid the hg dependency, it also means that every
> exported tree that is built without hg or .hg will have not
> only missing information, but will also be compatible to
> one another.  Considering that it is a common practice to
> remove the VCS data in distributions, I suggest we don't
> take this approach to avoid its consequences.
>
> This CL fixes the same problem in a different way: if a
> VERSION file at the top of the tree exists, use it at
> all times.  If it doesn't, fall back to using information
> from hg necessarily, and fail if that's not possible.  The
> error message when VERSION and hg are not available
> instructs users to handle it properly.
>
> The VERSION file can be generated with
> "src/version.bash -save" while hg is still around.
>
> R=golang-dev, rsc, gustavo
> CC=golang-dev
> http://codereview.appspot.com/4897043
>
>
> http://codereview.appspot.com/4897043/
>

[lucio, 2011-08-18 07:00:27]

Sorry folks, this was intended for a single recipient :-(

Lucio.

On 8/18/11, Lucio De Re <lucio.dere@gmail.com> wrote:
> I had occasion to convert this BASH script to Plan 9's RC and I would
> like to point out the following:
>
> 1. The -save option is not effective if a VERSION file already exists:
> the code exits before testing.
>
> 2. I don't properly understand this, so I can't be sure that I can
> improve it :-)
>
> # Get branch type
> BRANCH=release
> if [ "$(hg identify -b 2>/dev/null)" == "default" ]; then
> 	BRANCH=weekly
> fi
>
> My translation:
>
> BRANCH=`hg identify -b`
> case $BRANCH in
>   default) BRANCH=weekly;;
>   "") BRANCH=release;;
> esac
>
> may not be quite what you want, but your version seems to ignore any
> version other than "default" which doesn't seem right either.  I may
> of course be missing something, feel free to put me right.
>
> Lucio.
>
> On 8/15/11, n13m3y3r@gmail.com <n13m3y3r@gmail.com> wrote:
>> *** Submitted as
>> http://code.google.com/p/go/source/detail?r=ed3e04904ee7 ***
>>
>> build: support versioning without hg
>>
>> CL 4873048 introduced the ability to build without hg and
>> getting an "unknown" version.  While this approach works
>> to avoid the hg dependency, it also means that every
>> exported tree that is built without hg or .hg will have not
>> only missing information, but will also be compatible to
>> one another.  Considering that it is a common practice to
>> remove the VCS data in distributions, I suggest we don't
>> take this approach to avoid its consequences.
>>
>> This CL fixes the same problem in a different way: if a
>> VERSION file at the top of the tree exists, use it at
>> all times.  If it doesn't, fall back to using information
>> from hg necessarily, and fail if that's not possible.  The
>> error message when VERSION and hg are not available
>> instructs users to handle it properly.
>>
>> The VERSION file can be generated with
>> "src/version.bash -save" while hg is still around.
>>
>> R=golang-dev, rsc, gustavo
>> CC=golang-dev
>> http://codereview.appspot.com/4897043
>>
>>
>> http://codereview.appspot.com/4897043/
>>
>

[gustavo_niemeyer.net, 2011-08-18 15:08:48]

Hey Lucio,

> 1. The -save option is not effective if a VERSION file already exists:
> the code exits before testing.

You're right.. my follow up change to put precedence on VERSION at all
times broke this.  I'll fix it, thanks.

> may not be quite what you want, but your version seems to ignore any
> version other than "default" which doesn't seem right either.  I may
> of course be missing something, feel free to put me right.

This is more about the convention for versioning Go than about the
branch name itself.  We only have two versions at the moment: weekly
and release, so the logic feels right.

Please note that I haven't touched that logic.

-- 
Gustavo Niemeyer
http://niemeyer.net
http://niemeyer.net/plus
http://niemeyer.net/twitter
http://niemeyer.net/blog

-- I never filed a patent.