tables_in_string patch

tables_in_string_test.rb

require 'test/unit'

# These tests illustrate that the tables_in_string will not properly handle
# oracle table names containing valid non-word characters like '$' or those
# suffixed with a db link.  As a consequence, eager loading can revert to the
# left-outer-join strategy and ignore select statements on find (see
# http://gist.github.com/486750).
#
# To fix the issue, the regexp in tables_in_string needs to be updated to
# handle fully-qualified oracle names.  As you can see it's kinda ugly to do
# so, and obviously the oraclisms only apply to oracle.  I propose
# tables_in_string gets moved onto the adapter.
#
# To run this test:
#
#   % ruby tables_in_string_test.rb               # tests current, fails
#   % PATCH=true ruby tables_in_string_test.rb    # tests patch, passes
#
# == Example
#
# Works:
#
#   class Dept < ActiveRecord::Base
#     set_table_name 'dept'
#   end
#         
#   class Emp < ActiveRecord::Base
#     set_table_name 'emp'
#     belongs_to :dept, :select => 'id, name nombre'
#   end
#        
#   puts Emp.find(1, :include => :dept).dept.nombre
#
# Doesn't work:
#
#   class Dept < ActiveRecord::Base
#     set_table_name "schema$name.dept"
#   end
#         
#   class Emp < ActiveRecord::Base
#     set_table_name "schema$name.emp"
#     belongs_to :dept, :select => "id, name nombre"
#   end
#         
#   Emp.find(1, :include => :dept).dept.nombre   # !> NoMethodError
#
class TablesInStringTest < Test::Unit::TestCase
  
  NONQUOTED_OBJECT_NAME   = /[A-Za-z][A-z0-9$#]{0,29}/
  NONQUOTED_DATABASE_LINK = /[A-Za-z][A-z0-9$#\.@]{0,127}/
  
  # Pick which regexp to use based on the PATCH ENV variable
  TABLES_IN_STRING = ENV['PATCH'] == 'true' ?
    /((?:#{NONQUOTED_OBJECT_NAME}\.)?#{NONQUOTED_OBJECT_NAME}(?:@#{NONQUOTED_DATABASE_LINK})?)\..?/ :
    /([a-zA-Z_][\.\w]+).?\./
  
  # The original code in 3.0 -- see active_record/relation.rb
  #
  #   class String
  #     def blank?
  #       self !~ /\S/
  #     end
  #   end
  #
  #   def tables_in_string(string)
  #     return [] if string.blank?
  #     # ignore raw_sql_ that is used by Oracle adapter as alias for limit/offset subqueries
  #     string.scan(/([a-zA-Z_][\.\w]+).?\./).flatten.map(&:downcase).uniq - ['raw_sql_']
  #   end
  #
  def tables_in_string(string)
    return [] if string !~ /\S/
    string.scan(TABLES_IN_STRING).flatten.map {|str| str.downcase }.uniq - ['raw_sql_']
  end
  
  #
  # tables_in_string test
  #
  
  def test_tables_in_string
    assert_equal %w{one two three}, tables_in_string('one.a, two.b, three.c')
  end
  
  def test_tables_in_fully_qualified_string
    assert_equal %w{
      tablename
      schemaname.tablename
      schemaname.tablename@dblink
    }, tables_in_string('tablename.a, schemaname.tablename.b, schemaname.tablename@dblink.c')
  end
  
  def test_tables_in_string_with_acceptable_non_word_characters
    assert_equal %w{
      abc$#_123.abc$#_123@abc$#@._123
    }, tables_in_string('abc$#_123.abc$#_123@abc$#@._123.columnone, abc$#_123.abc$#_123@abc$#@._123.columntwo')
  end
end