Rails 3.07 dup issue

rubyonrails-talk
1

Hi not sure if this is where I should post this problem but since upgrading to rails 3.07 dup is not working as expected for Hash

basically in method I have this         dup_row = row.dup         #then I delete a row of my original hash         row[:athlete].delete(:sports) if !row[:athlete][:sports].nil?

   pretty simple but what is happening is it is deleting from the dup and the original here is the debug code of the original and dup just after deleting the sports

original hash values

{"athlete"=>{"first_name"=>"DaveG5600", "gender"=>"M", "hometown_id"=>"40", "birthplace_id"=>"30", "last_name"=>"test"}, "leagues"=>{"league"=>{"id"=>"821", "start_year"=>"1983", "end_year"=>"2003"}}, "clubs"=>{"club"=>[{"id"=>"11802", "start_year"=>nil, "end_year"=>nil}, {"id"=>"1403", "start_year"=>nil, "end_year"=>nil}]}, "schools"=>{"school"=>{"id"=>nil, "start_year"=>nil, "end_year"=>nil}}, "sports"=>{"sport"=>{"id"=>"102", "start_year"=>"1985", "end_year"=>"1986", "sport_roles"=>"10"}}}}

dup row (notice sports is missing which even though I am not deleting from this hash) {"athlete"=>{"first_name"=>"DaveG5600", "gender"=>"M", "hometown_id"=>"40", "birthplace_id"=>"30", "last_name"=>"test"}, "leagues"=>{"league"=>{"id"=>"821", "start_year"=>"1983", "end_year"=>"2003"}}, "clubs"=>{"club"=>[{"id"=>"11802", "start_year"=>nil, "end_year"=>nil}, {"id"=>"1403", "start_year"=>nil, "end_year"=>nil}]}, "schools"=>{"school"=>{"id"=>nil, "start_year"=>nil, "end_year"=>nil}}}}

row (this is where I expect to have the sport value deleted which is does) {"athlete"=>{"first_name"=>"DaveG5600", "gender"=>"M", "hometown_id"=>"40", "birthplace_id"=>"30", "last_name"=>"test"}, "leagues"=>{"league"=>{"id"=>"821", "start_year"=>"1983", "end_year"=>"2003"}}, "clubs"=>{"club"=>[{"id"=>"11802", "start_year"=>nil, "end_year"=>nil}, {"id"=>"1403", "start_year"=>nil, "end_year"=>nil}]}, "schools"=>{"school"=>{"id"=>nil, "start_year"=>nil, "end_year"=>nil}}}}   e

2

Hi not sure if this is where I should post this problem but since upgrading to rails 3.07 dup is not working as expected for Hash

basically in method I have this dup_row = row.dup #then I delete a row of my original hash row[:athlete].delete(:sports) if !row[:athlete][:sports].nil?

pretty simple but what is happening is it is deleting from the dup and the original here is the debug code of the original and dup just after deleting the sports

Hash#dup does a shallow copy in ruby (ie ruby doesn't recursively dup the hash's contents) - this is expected.

Fred

3

If you want deep copy you should use Marshal:

class Hash   def deep_dup     Marshal::load(Marshal::dump(self))   end end

foo = {:b=>{:c=>{:d=>1}}} bar = foo.deep_dup

foo[:b][:c][:d] = 2 p foo # => {:b=>{:c=>{:d=>2}}} p bar # => {:b=>{:c=>{:d=>1}}}