#1111 ✓duplicate
robert

Marshal.dump string malformed after database save.

Reported by robert | October 28th, 2009 @ 03:11 AM

Hello,

I've looked into this, and I can only come to the conclusion that DataMapper is malforming the string returned by Marshal.dump() when saved to the database.

I've wrote a test case to reproduce this problem:

require 'dm-core'

class Session

include DataMapper::Resource

property :id, Serial property :dump, String, :length => 10_000

end

DataMapper.setup :default, "sqlite3://#{Dir.getwd}/out.sqlite"
DataMapper.auto_migrate!

class MyClass

def initialize

@foo = {}
@bar = {}

end

def dump

puts (dump = Marshal.dump(self)).inspect
Session.create :dump => dump

end

end

my = MyClass.new

dump() will print the string before it is saved to the database.

At this point, it looks like this:

"\x04\bo:\fMyClass\a:\t@foo{\x00:\t@bar{\x00"

my.dump

Lets see if we can load that dump

Yup, no problem.

Marshal.load "\x04\bo:\fMyClass\a:\t@foo{\x00:\t@bar{\x00"

Lets try to read that string from the database, but we get:

=> "\x04\bo:\fMyClass\a:\t@foo{"

puts (Session.first(:id => 1).dump).inspect

Malformed dump now, we can't load this.

=> Raises ArgumentError, Marshal data too short.

puts Marshal.load Session.first(:id => 1).dump

If @foo, and @bar aren't empty hashes, it works fine.

Comments and changes to this ticket

  • Xavier Shay

    Xavier Shay December 2nd, 2010 @ 11:48 PM

    • State changed from “new” to “confirmed”
    • Milestone order changed from “0” to “0”

    Confirmed. Problem is trying to store \x00 in a String type. (Currently Binary does nothing special, just creates a BLOB but still truncates at the null byte).

    require 'rubygems'
require 'dm-core'
require 'dm-migrations'

DataMapper::Logger.new($stdout, :debug)
DataMapper.setup(:default, 'sqlite3://:memory:') 

class Session

  include DataMapper::Resource

  property :id, Serial 
  property :dump, Binary, :length => 10_000

end
Session.auto_migrate!

class MyClass

  def initialize
    @foo = {}
    @bar = {}
  end

  def dump
    puts (dump = Marshal.dump(self)).inspect
    Session.create :dump => dump
  end

end

my = MyClass.new
my.dump
puts Session.first.dump.inspect
puts Marshal.load( Session.first.dump)
  • Xavier Shay

    Xavier Shay December 2nd, 2010 @ 11:49 PM

    • State changed from “confirmed” to “duplicate”

    #1071, scheduled for 1.0.3, will fix this assuming you use the Binary type rather than String.

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