Support Rails 3.2

[tfausak]

The only thing this library uses from Rails 4 is the new Object#deep_dup behavior. This pull request backports that behavior to support Rails 3.2.

[tfausak]

This was necessary because minitest does not get pulled in as a transitive dependency with activemodel 3.2.

[morgoth]

I can see that there are more problems on 3.2.x:

# 3.2.0
bundle exec rake
/home/wojtek/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/activesupport-3.2.0/lib/active_support/core_ext/module/deprecation.rb:7:in `deprecate': uninitialized constant ActiveSupport::Deprecation (NameError)
    from /home/wojtek/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/activemodel-3.2.0/lib/active_model/naming.rb:13:in `<class:Name>'
    from /home/wojtek/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/activemodel-3.2.0/lib/active_model/naming.rb:7:in `<module:ActiveModel>'
    from /home/wojtek/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/activemodel-3.2.0/lib/active_model/naming.rb:6:in `<top (required)>'
    from /home/wojtek/Projects/active_model-errors_details/test/test_errors_details.rb:5:in `require'
    from /home/wojtek/Projects/active_model-errors_details/test/test_errors_details.rb:5:in `<top (required)>'
    from /home/wojtek/.rbenv/versions/2.2.2/lib/ruby/2.2.0/rake/rake_test_loader.rb:10:in `require'
    from /home/wojtek/.rbenv/versions/2.2.2/lib/ruby/2.2.0/rake/rake_test_loader.rb:10:in `block (2 levels) in <main>'
    from /home/wojtek/.rbenv/versions/2.2.2/lib/ruby/2.2.0/rake/rake_test_loader.rb:9:in `each'
    from /home/wojtek/.rbenv/versions/2.2.2/lib/ruby/2.2.0/rake/rake_test_loader.rb:9:in `block in <main>'
    from /home/wojtek/.rbenv/versions/2.2.2/lib/ruby/2.2.0/rake/rake_test_loader.rb:4:in `select'
    from /home/wojtek/.rbenv/versions/2.2.2/lib/ruby/2.2.0/rake/rake_test_loader.rb:4:in `<main>'
rake aborted!

# 3.2.1 upto 3.2.12
bundle exec rake
MiniTest::Unit::TestCase is now Minitest::Test. From /home/wojtek/Projects/active_model-errors_details/test/test_errors_details.rb:7:in `<top (required)>'
Run options: --seed 31318

# Running:

...E...

Finished in 0.007318s, 956.5743 runs/s, 1366.5347 assertions/s.

  1) Error:
TestErrorsDetails#test_dup_duplicates_details:
NoMethodError: private method `initialize_dup' called for #<ActiveModel::Errors:0x007fa385198ae0>
    /home/wojtek/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/activemodel-3.2.1/lib/active_model/errors.rb:90:in `dup'
    /home/wojtek/Projects/active_model-errors_details/test/test_errors_details.rb:69:in `test_dup_duplicates_details'

It was fixed in 3.2.13 in rails/rails#8405

I'll set minimum required version to 3.2.13 - I hope this is fine for you.
I would also like to avoid maintaining 3.2.x compatibility in a long term.

[tfausak]

Oops, I should have tested with 3.2.0. I want to use this library with orgsync/active_interaction, which supports Rails 3.2.0. We will support that at least until Rails 5 is released. If you do not want to support Rails 3.2.x, we can fork this gem to add support.

[morgoth]

After your changes it works with 3.2, so no need to fork.
I think that setting 3.2.13 as minimum dependency shouldn't be a problem. Latest 3.2 series is 3.2.21 so there were lot of releases.
If someone would like to use new version of active_interaction he shouldn't have any problem with upgrading rails itself.