date_select causing wrong date when using discard_year and include_blank

[grantzau]

When using discard_year together with include_blank the date_helper sets year to "1" using a hidden field. That somehow causes the saved date value to be altered in a way, that the "day" part of the date increases by two ...

So choosing "january" "1" from the two selects saves the date "0001-01-03" instead of "0001-01-01"

But if the value of the year part is set anything from 201 upto 300 or 1583 upto 2017 the day and month parts remains as entered, which makes no sense to me.

Steps to reproduce

rails new app_test_discard_year
cd app_test_discard_year/
rails generate scaffold test_day day:date
rails db:migrate

Add { discard_year: true, include_blank: true } to the date_select in

app/views/test_days/_form.html.erb

so it looks like this <%= f.date_select :day, { discard_year: true, include_blank: true } %>

http://localhost:3000/test_days

Start server and try creating a new "Test Day" choosing january 1st and save.

Rails 5.0.2
ruby 2.4.0p0

[nynhex]

@grantzau I've reproduced this with Rails 5.0.2 and Ruby 2.4.0 can confirm.

[CharlieHawker]

Also present in 5.1.0.rc1 with Ruby 2.4.0p0

[CharlieHawker]

A bit of further digging and this doesn't seem to relate to how date_select passes the params through to rails - it seems to be to do with how ActiveRecord does it's type casting; the parameters in the log are as expected:

Parameters: {"utf8"=>"✓", "authenticity_token"=>"z1Wri0PN6F8ngRgUODePl3oJNvEB8CM9Gf5mJQWp5SjWu0qHhalVHsEIj7jPbZtsj5W21BVbSUHY4NCc0kQbqA==", "test_day"=>{"day(1i)"=>"1", "day(2i)"=>"1", "day(3i)"=>"1"}, "commit"=>"Create Test day"}

and if you use the rails console to create a TestDate with the same attributes, you get the same issue:

2.4.0 :085 > d = TestDay.new({"day(1i)"=>"1", "day(2i)"=>"1", "day(3i)"=>"1"})
 => #<TestDay id: nil, day: "0001-01-03", created_at: nil, updated_at: nil> 
2.4.0 :086 > d
 => #<TestDay id: nil, day: "0001-01-03", created_at: nil, updated_at: nil> 

Digging a little deeper, the attribute assignment code in lib/active_record/attribute_assignment.rb seems to prepare the hash as expected for the 'day' attribute; so the issue I believe is arising in the ActiveRecord::Attribute type casting code.

As a further proof, you can see the uncast attribute value of a new TestDay is showing correctly:

2.4.0 :087 > d = TestDay.new({"day(1i)"=>"1", "day(2i)"=>"1", "day(3i)"=>"1"})
 => #<TestDay id: nil, day: "0001-01-03", created_at: nil, updated_at: nil> 
2.4.0 :088 > d.day_before_type_cast
 => {1=>1, 2=>1, 3=>1} 

[grantzau]

@CharlieHawker Thanks for clarifying, I agree that the problem seems to be in the ActiveRecord library. Personally I haved fixed it by setting the default value of year to "2001" instead.

I don´t know if it makes sense to do the same in the rails/date_helper.rb - as the year is discarded anyway, setting it to 2001 has no side-effect from my point of view, only the possitive effect, that it makes the day/month select work ... ! :)

action_view/helpers/date_helper.rb#L824

[rails-bot]

This issue has been automatically marked as stale because it has not been commented on for at least three months.
The resources of the Rails team are limited, and so we are asking for your help.
If you can still reproduce this error on the 5-1-stable branch or on master, please reply with all of the information you have about it in order to keep the issue open.
Thank you for all your contributions.

[grantzau]

Year is still set to "1" in 5-1 stable so the problem is still there