From: Eric Hodel <drbrain@...7.net>
Date: 2009-03-28T03:54:24+09:00
Subject: Re: Restrict Platform for RubyGem Update

On Mar 26, 2009, at 23:32, Jj Jj wrote:
> Ryan Davis wrote:
>> On Mar 26, 2009, at 23:11 , Jj Jj wrote:
>>
>>> I am working on a windows box attempting to develop a rails
>>> application.
>>> Is there a way to ensure "gem update" or "gem install x" will not
>>> try to
>>> download and compile native ruby gems ?
>>
>> rubygems will download any platform specific gem first if it exists.
>> Otherwise it'll download the "ruby" platform. If that gem specifies
>> that it has extensions to build, it'll try to build them. There may  
>> be
>> some extra way to specify that you don't want builds to occur, but I
>> don't know it. See `gem help install` for more.
>
> Thank you for the information. I have reviewed the information for  
> both
> install and update.
>
> Does anyone if there is a way to not default back to the ruby  
> platform ?

As of RubyGems 1.3 (IIRC), a failed build shouldn't result in an  
installed gem.

I don't have MySQL installed on my system, but I forced an install of  
the gem:

$ gem list mysql

*** LOCAL GEMS ***

mysql (2.5.1)
$ gem list mysql

*** LOCAL GEMS ***

mysql (2.5.1)
$ sudo gem update mysql
Updating installed gems
Updating mysql
Building native extensions.  This could take a while...
ERROR:  Error installing mysql:
	ERROR: Failed to build gem native extension.
[...]
Gem files will remain installed in /Library/Ruby/Gems/1.8/gems/ 
mysql-2.5.1 for inspection.
Results logged to /Library/Ruby/Gems/1.8/gems/mysql-2.5.1/gem_make.out
Nothing to update
$ gem list mysql

*** LOCAL GEMS ***

mysql (2.5.1)
$

So nothing was updated, even though RubyGems tried it's hardest to do  
what you want.