At least, now that I know that this behavior is intentional in Rails I
documented myself in my own class so that other developers could also
understand the reason I'm depending on full ActionView when I really
depend only on NumberHelper:
require 'bigdecimal'
# In Rails, if you need action_view/helpers/number_helper you have to
require 'action_view',
# then 'action_view/helpers and finally
'action_view/helpers/number_helper'. Pretty stupid but we don't control
# Rails. Since ActionView will load all components, we don't need to
require the other files, just 'action_view':
require 'action_view'
#require 'action_view/helpers/number_helper'
Em 08-02-2013 15:53, Rodrigo Rosenfeld Rosas escreveu:
Is this documented somewhere? Since it doesn't follow any best
practices I think this particular Rails behavior should be documented,
right?
Em 08-02-2013 15:51, Rafael Mendonça França escreveu:
The correct way to use any one of the rails pieces is to require the
framework file first.
You have to do
|require 'action_view' # this file only loads what is needed to use the
framework inside and outside the rails scope
require 'action_view/helpers'|
Rafael Mendonça França
http://twitter.com/rafaelfranca
https://github.com/rafaelfranca
On Fri, Feb 8, 2013 at 3:46 PM, Rodrigo Rosenfeld Rosas
<[email protected] <mailto:[email protected]>> wrote:
I know it is tangential. I was just explaining why I don't agree
with the current approach because non Rails code could rely only
on 'action_view/helpers', don't you agree? How are they supposed
to know that they should first require 'active_support/rails' or
any other entry point?
I don't think it is fine to just assume that ActionView classes
only make sense in within the Rails context. This is an unsafe
assumption that I don't agree with.
Em 08-02-2013 15:42, Xavier Noria escreveu:
I am only explaining why autoload and concern have no explicit
requires in that file. That was a tangential question you did
not directly related to the exception.
Sent from my iPhone
On 08/02/2013, at 18:36, Rodrigo Rosenfeld Rosas
<[email protected] <mailto:[email protected]>> wrote:
I don't understand what you mean. In my unit tests involving
ParseFormatUtils for instance Rails is never loaded and my
application doesn't even use ActiveRecord.
But my tests weren't complaining anyway because they don't
autoload ActionView/Helpers.
Also, even if I explicitly required as/rails it wouldn't fix
the situation for my case.
This is what's happening in a simplified way:
./test.rb:
autoload :A, 'a'
require 'a/b'
./lib/a.rb:
module A
autoload :B, 'a/b'
include B
end
./lib/a/b.rb:
module A
module B
end
end
ruby -I lib test.rb
This is enough to create the circular dependency error. Maybe
this is one of the reasons why Matz wants to remove autoload
from Ruby...
Sorry but I don't have any suggestions right now that would
make require 'a/b' work if 'a' is set to be autoloaded and 'a'
requires 'b' which depends on 'a'...
Unless we create some 'action_view/helpers/all.rb' file. Would
that be acceptable?
Best,
Rodrigo.
Em 08-02-2013 15:26, Xavier Noria escreveu:
No, no, as/rails.rb is already required by the entry point
of every component (except AS). That is a given in the
context of a Rails application, and
gem 'active_record'
does that if standalone.
Sent from my iPhone
On 08/02/2013, at 18:12, Rodrigo Rosenfeld Rosas
<[email protected] <mailto:[email protected]>> wrote:
Em 08-02-2013 15:00, Xavier Noria escreveu:
Some very common files are loaded at the entry point of
every component, to avoid repeating their require again and
again:
https://github.com/rails/rails/blob/master/activesupport/lib/active_support/rails.rb
But shouldn't helpers.rb require 'active_support/rails' then
instead of just 'active_support/benchmarkable'?
Otherwise it should be documented that we're not supposed to
require specific parts of some libraries included in Rails...
That way I'd know (although surprised) that I'm not supposed
to require 'action_view/helpers/number_helper' but simply
'action_view/helpers' (or just 'action_view'?)
As for the autoload + include, I don't really know, maybe it
is a fancy way to avoid writing a file path. Seems
unnecessary to me at first glance. Maybe someone else from
the team has a better justification?
Sent from my iPhone
On 08/02/2013, at 17:45, Rodrigo Rosenfeld Rosas
<[email protected] <mailto:[email protected]>> wrote:
Em 08-02-2013 13:03, Xavier Noria escreveu:
On Fri, Feb 8, 2013 at 3:18 PM, Rodrigo Rosenfeld Rosas
<[email protected]> <mailto:[email protected]> wrote:
Em 08-02-2013 12:06, Xavier Noria escreveu:
Seems unrelated to dependencies.rb, most likely a missing require
somewhere within Rails.
It can be the case that it does not show up in production because of eager
loading.
Any ideas why helpers.rb is loaded when you write code like below?
module ActionView
module Helpers
module NumberHelper
Is this normal MRI behavior or is this caused by dependencies.rb?
Ruby on Rails itself does not use dependencies.rb to load its code. It
is a regular Ruby library that uses requires and Kernel#autoload with
some added sugar. AS::Dependencies only covers application constant
autoloading.
The thing goes like this: When an application boots in any environment
action_view.rb is loaded. When that file is executed an autoload for
:Helpers is configured under ActionView. In a default setup,
helpers.rb is not yet loaded. That is, if you run
rails runner 1
helpers.rb is not loaded (at least in 3-2-stable, not that we are
explaining any contract, only load order execution to follow what
happens in your exception).
But if you force the evaluation of the constant as in your example above:
module ActionView
module Helpers
...
end
end
that autoload is triggered because the interpreter checks whether
"Helpers" is a constant defined in the module object stored in
ActionView. Therefore, helpers.rb is interpreted and sets in turn an
autoload for NumberHelper below AV::Helpers.
So, module Helpers in that snippet *reopens* a module object defined
via the autoload, rather than creating the module object. The
execution follows and the same happens with the "NumberHelper"
constant down below. The interpreter checks whether it belongs to the
module object stored in AV::Helpers. Since it is unknown and there is
an autoload for it it gets triggered, and loads... well the very
number_helper.rb whose execution we were in the middle of (not sure
this sentence is valid English :).
I suspect there is a circularity here that is showing up that way.
Would need to dig deeper to fully explain how this ends up in an
exception, maybe I'll do it tonight, but in the meantime here's some
context in case it helps.
It makes total sense. What doesn't make sense is the source
of helpers.rb to me:
https://github.com/rails/rails/blob/master/actionpack/lib/action_view/helpers.rb
First it should explicitly require (or require_dependency)
'active_support/autoload' and 'active_support/concern', right?
But then, why using autoload if you're just including all
modules next?
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