Getting the version number for rubygems?

ruby-talk
1

Hi,

In ruport I have a tool that generates a bunch of boilerplate code for
folks, and in it, I use require_gem to lock the files down to a
specific version of Ruport.

I'd like to make this friendly to RubyGems 0.9.1 by using the gem
method rather than require_gem when people have 0.9.1, but want to
generate require_gem for older versions.

So basically, is there a constant or method I can call that'll give me
back the version of rubygems that i'm running?

2

Well, from the command line you can call "gem -v" to get the version.
Perhaps there is something you can do with that.

Jonathan

···

--
Posted via http://www.ruby-forum.com/.

3

Gregory Brown wrote:

I'd like to make this friendly to RubyGems 0.9.1 by using the gem
method rather than require_gem when people have 0.9.1, but want to
generate require_gem for older versions.

So basically, is there a constant or method I can call that'll give me
back the version of rubygems that i'm running?

For 0.8.11 and 0.9.0, this should work:
   require 'rubygems/rubygems_version'
   p Gem::RubyGemsVersion
but no promises on any other version. Check the SCM history.

That said, why not rescue NoMethodError?

Devin

4

In ruport I have a tool that generates a bunch of boilerplate code for
folks, and in it, I use require_gem to lock the files down to a
specific version of Ruport.

I'd like to make this friendly to RubyGems 0.9.1 by using the gem
method rather than require_gem when people have 0.9.1, but want to
generate require_gem for older versions.

Just use #gem, and don't bother being backwards-compatible. RubyGems older than 0.9.1 has a serious security exploit. (About 20% of rubyists are running a version of RubyGems without #gem (prior to 0.9.1's release).)

So basically, is there a constant or method I can call that'll give me
back the version of rubygems that i'm running?

Don't think so hard:

require 'rubygems'
Kernel.respond_to? :gem

And now for the real answer to your question:

The rubygems constant is in Gem::RubyGemsVersion, which you can get from 'rubygems/rubygems_version'. Kernel#gem first appeared in 0.9.0.

···

On Jan 20, 2007, at 20:11, Gregory Brown wrote:

--
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net

I LIT YOUR GEM ON FIRE!

5

> In ruport I have a tool that generates a bunch of boilerplate code for
> folks, and in it, I use require_gem to lock the files down to a
> specific version of Ruport.
>
> I'd like to make this friendly to RubyGems 0.9.1 by using the gem
> method rather than require_gem when people have 0.9.1, but want to
> generate require_gem for older versions.

Just use #gem, and don't bother being backwards-compatible. RubyGems
older than 0.9.1 has a serious security exploit. (About 20% of
rubyists are running a version of RubyGems without #gem (prior to
0.9.1's release).)

I'll probably do this by the next release, but the one coming up in a
week or two i'd like to give people a bit of grace period.

> So basically, is there a constant or method I can call that'll give me
> back the version of rubygems that i'm running?

Don't think so hard:

require 'rubygems'
Kernel.respond_to? :gem

Yep, that's better. thanks.

···

On 1/20/07, Eric Hodel <drbrain@segment7.net> wrote:

On Jan 20, 2007, at 20:11, Gregory Brown wrote:

6

require 'rubygems'

unless Kernel.respond_to? :gem
  alias gem require_gem
end

gem 'ruport'

That should work I believe...

--Jeremy

···

On 1/20/07, Gregory Brown <gregory.t.brown@gmail.com> wrote:

On 1/20/07, Eric Hodel <drbrain@segment7.net> wrote:
> On Jan 20, 2007, at 20:11, Gregory Brown wrote:
> > In ruport I have a tool that generates a bunch of boilerplate code for
> > folks, and in it, I use require_gem to lock the files down to a
> > specific version of Ruport.
> >
> > I'd like to make this friendly to RubyGems 0.9.1 by using the gem
> > method rather than require_gem when people have 0.9.1, but want to
> > generate require_gem for older versions.
>
> Just use #gem, and don't bother being backwards-compatible. RubyGems
> older than 0.9.1 has a serious security exploit. (About 20% of
> rubyists are running a version of RubyGems without #gem (prior to
> 0.9.1's release).)

I'll probably do this by the next release, but the one coming up in a
week or two i'd like to give people a bit of grace period.

> > So basically, is there a constant or method I can call that'll give me
> > back the version of rubygems that i'm running?
>
> Don't think so hard:
>
> require 'rubygems'
> Kernel.respond_to? :gem

Yep, that's better. thanks.

--
My free Ruby e-book:
http://www.humblelittlerubybook.com/book/

My blogs:

http://www.rubyinpractice.com/

7

instead of alias i'll use alias_method. But I bet that would work.

···

On 1/21/07, Jeremy McAnally <jeremymcanally@gmail.com> wrote:

require 'rubygems'

unless Kernel.respond_to? :gem
  alias gem require_gem
end

gem 'ruport'

That should work I believe...

8

NO! NO! NO! NO! NO! NO! NO! NO! NO! NO! NO! NO! NO!

#gem and #require_gem do different things (autorequire).

You'll screw over other gems by aliasing things around.

Instead, just fall back to require_gem when gem isn't loaded.

if Kernel.respond_to? :gem then
   gem blah
else
   require_gem blah
end

DO NOT go aliasing methods on top of each other. #require and #require_gem do different things, much like #sub and #sub! do different things, respect that.

···

On Jan 20, 2007, at 21:03, Jeremy McAnally wrote:

require 'rubygems'

unless Kernel.respond_to? :gem
alias gem require_gem
end

gem 'ruport'

That should work I believe...

--
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net

I LIT YOUR GEM ON FIRE!

9

Gregory Brown wrote:

instead of alias i'll use alias_method.

Why? (Curious, not argumentative.)

Devin

10

Maybe you should tell the Rails team because I'm fairly sure that's
how they planned on handling it...

http://dev.rubyonrails.org/ticket/6886

--Jeremy

···

On 1/21/07, Eric Hodel <drbrain@segment7.net> wrote:

On Jan 20, 2007, at 21:03, Jeremy McAnally wrote:
> require 'rubygems'
>
> unless Kernel.respond_to? :gem
> alias gem require_gem
> end
>
> gem 'ruport'
>
> That should work I believe...

NO! NO! NO! NO! NO! NO! NO! NO! NO! NO! NO! NO! NO!

#gem and #require_gem do different things (autorequire).

You'll screw over other gems by aliasing things around.

Instead, just fall back to require_gem when gem isn't loaded.

if Kernel.respond_to? :gem then
   gem blah
else
   require_gem blah
end

DO NOT go aliasing methods on top of each other. #require and
#require_gem do different things, much like #sub and #sub! do
different things, respect that.

--
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net

I LIT YOUR GEM ON FIRE!

--
My free Ruby e-book:
http://www.humblelittlerubybook.com/book/

My blogs:

http://www.rubyinpractice.com/

11

> require 'rubygems'
>
> unless Kernel.respond_to? :gem
> alias gem require_gem
> end
>
> gem 'ruport'
>
> That should work I believe...

NO! NO! NO! NO! NO! NO! NO! NO! NO! NO! NO! NO! NO!

There you go being an asshole again Eric. (please stop)

if Kernel.respond_to? :gem then
   gem blah
else
   require_gem blah
end

DO NOT go aliasing methods on top of each other. #require and
#require_gem do different things, much like #sub and #sub! do
different things, respect that.

I'm aware of this. I actually need to just lock version and do a
normal require.

I'll do it that way.

···

On 1/21/07, Eric Hodel <drbrain@segment7.net> wrote:

On Jan 20, 2007, at 21:03, Jeremy McAnally wrote:

12

alias is really a somewhat scary function. I can't think of a good
example right now, but i've seen a couple different surprising things
with alias, wheras alias_method is simple and has normal behaviour.
Perhaps someone on the list can help me out with this.

···

On 1/21/07, Devin Mullins <twifkak@comcast.net> wrote:

Gregory Brown wrote:
> instead of alias i'll use alias_method.
Why? (Curious, not argumentative.)

13

I guess it really is just the method vs. keyword thing.
alias is available everywhere, which means you might be aliasing in
the wrong place

Also, alias can work on global variables and regex backreferences.

it's also scary to me to see: alias new_method old_method
where alias_method :new_method, :old_method seems more natural to me.

I think I may have been overly fearful about the use of alias, but I
guess there is no good reason not to use it as long as you know what
you're doing.

regards,
-greg

···

On 1/21/07, Devin Mullins <twifkak@comcast.net> wrote:

Gregory Brown wrote:
> instead of alias i'll use alias_method.
Why? (Curious, not argumentative.)

14

well, keyword. alias_method is actually a method, alias is not.

···

On 1/21/07, Gregory Brown <gregory.t.brown@gmail.com> wrote:

On 1/21/07, Devin Mullins <twifkak@comcast.net> wrote:
> Gregory Brown wrote:
> > instead of alias i'll use alias_method.
> Why? (Curious, not argumentative.)

alias is really a somewhat scary function.

15

You're seeing phantoms. There's no difference between alias_method and alias on the inside.

       case NODE_ALIAS:
         if (NIL_P(ruby_class)) {
             rb_raise(rb_eTypeError, "no class to make alias");
         }
         rb_alias(ruby_class, rb_to_id(rb_eval(self, node->u1.node)),
                              rb_to_id(rb_eval(self, node->u2.node)));

static VALUE
rb_mod_alias_method(mod, newname, oldname)
     VALUE mod, newname, oldname;
{
     rb_alias(mod, rb_to_id(newname), rb_to_id(oldname));

···

On Jan 20, 2007, at 21:29, Gregory Brown wrote:

On 1/21/07, Devin Mullins <twifkak@comcast.net> wrote:

Gregory Brown wrote:
> instead of alias i'll use alias_method.
Why? (Curious, not argumentative.)

alias is really a somewhat scary function. I can't think of a good
example right now, but i've seen a couple different surprising things
with alias, wheras alias_method is simple and has normal behaviour.
Perhaps someone on the list can help me out with this.

--
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net

I LIT YOUR GEM ON FIRE!

16

Hah. That'd explain why I am scared.

I forget what the cases were, but Sebastian Delmont did a talk on
things he found surprising in Ruby, and the stuff he pulled up for
alias vs. alias_method was pretty convincing.

···

On 1/21/07, Eric Hodel <drbrain@segment7.net> wrote:

On Jan 20, 2007, at 21:29, Gregory Brown wrote:
> On 1/21/07, Devin Mullins <twifkak@comcast.net> wrote:
>> Gregory Brown wrote:
>> > instead of alias i'll use alias_method.
>> Why? (Curious, not argumentative.)
>
> alias is really a somewhat scary function. I can't think of a good
> example right now, but i've seen a couple different surprising things
> with alias, wheras alias_method is simple and has normal behaviour.
> Perhaps someone on the list can help me out with this.

You're seeing phantoms. There's no difference between alias_method
and alias on the inside.

17

Well, you can override alias_method() if needed, but not alias.

James Edward Gray II

···

On Jan 21, 2007, at 1:24 AM, Eric Hodel wrote:

On Jan 20, 2007, at 21:29, Gregory Brown wrote:

On 1/21/07, Devin Mullins <twifkak@comcast.net> wrote:

Gregory Brown wrote:
> instead of alias i'll use alias_method.
Why? (Curious, not argumentative.)

alias is really a somewhat scary function. I can't think of a good
example right now, but i've seen a couple different surprising things
with alias, wheras alias_method is simple and has normal behaviour.
Perhaps someone on the list can help me out with this.

You're seeing phantoms. There's no difference between alias_method and alias on the inside.

18

any slides online?

···

On Jan 20, 2007, at 23:33, Gregory Brown wrote:

On 1/21/07, Eric Hodel <drbrain@segment7.net> wrote:

On Jan 20, 2007, at 21:29, Gregory Brown wrote:
> On 1/21/07, Devin Mullins <twifkak@comcast.net> wrote:
>> Gregory Brown wrote:
>> > instead of alias i'll use alias_method.
>> Why? (Curious, not argumentative.)
>
> alias is really a somewhat scary function. I can't think of a good
> example right now, but i've seen a couple different surprising things
> with alias, wheras alias_method is simple and has normal behaviour.
> Perhaps someone on the list can help me out with this.

You're seeing phantoms. There's no difference between alias_method
and alias on the inside.

Hah. That'd explain why I am scared.

I forget what the cases were, but Sebastian Delmont did a talk on
things he found surprising in Ruby, and the stuff he pulled up for
alias vs. alias_method was pretty convincing.

--
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net

I LIT YOUR GEM ON FIRE!

19

And that changes or invalidates what Eric said... how? Not only did he qualify with "on the inside" but he also backed it up by showing said inside.

···

On Jan 21, 2007, at 12:07 PM, James Edward Gray II wrote:

On Jan 21, 2007, at 1:24 AM, Eric Hodel wrote:

You're seeing phantoms. There's no difference between alias_method and alias on the inside.

Well, you can override alias_method() if needed, but not alias.

20

I didn't see them on the nycruby list. :-/
I'll email him and see if they're posted anywhere

···

On 1/21/07, Eric Hodel <drbrain@segment7.net> wrote:

any slides online?