[ydah]

Concurrent validations can overwrite the shared validator's @converter, causing restrictions to be parsed in another attribute's time zone.

This reproduction forces another thread's UTC validation to run between the local value conversion and restriction check:

require 'active_model'
require 'validates_timeliness'

class Event
  include ActiveModel::Model
  attr_accessor :local_datetime, :utc_datetime

  def self.skip_time_zone_conversion_for_attributes
    [:utc_datetime]
  end

  validates_datetime :local_datetime, :utc_datetime,
    before: '2010-01-01 12:00:00', allow_nil: true
end

Time.zone = 'Australia/Melbourne'
local_record = Event.new(local_datetime: Time.utc(2010, 1, 1, 11))
utc_record = Event.new(utc_datetime: Time.utc(2010, 1, 1, 11))

validator = Event.validators.first
validator.define_singleton_method(:validate_restrictions) do |record, *args|
  Thread.new { utc_record.valid? }.value if record.equal?(local_record)
  super(record, *args)
end

p local_record.valid? # Before: true; after: false

The local value is 22:00 in Melbourne and should violate the 12:00 restriction. Before the fix, the UTC converter incorrectly accepts it.

Keep the converter local to validate_each and pass it to validate_restrictions so each validation uses its own converter.

[adzap]

Thanks!