$ diff rb18 rb19

Our Goal

OS

• Debian to Ubuntu 12

PostgreSQL

• 8.4 to 9.1

Ruby

• 1.8.7 to 2.0

Rails

• 2.3.18 to 3.2 (4.0?)

Other used gems

begin

  upgrade(:ruby_18, :ruby_19)

rescue

  fix and retry

end

Syntax Check First

$ find . -name '*.rb' -type f -exec ruby -c {} \; | \
    grep -v 'Syntax OK'

Colon in Ruby 1.8

1. case ... when

case
when 1: 'a'
when 2: 'b'
when 3: 'c'
end

1. if, unless, while, until

if a == b: c else d end

Colon in Ruby 1.9

1. case ... when

case
when 1 then 'a'
when 2 then 'b'
when 3 then 'c'
end

1. if, unless, while, until

if a == b then c else d end

Parentheses in Ruby 1.8

[f 1, 2]

Parentheses in Ruby 1.8

[f 1, 2] # ambiguous! [f(1), 2] ? or [f(1, 2)] ?

Parentheses in Ruby 1.9

[f(1, 2)]

Encoding

• Ruby 1.8: Simple & Easy
• Ruby 1.9: Powerful

In Rails 2.3

content = File.read '/bin/sh'
content.blank?
# => ArgumentError: invalid byte sequence in UTF-8

PATCH

if defined?(Encoding)
  class String
    def blank?
      begin
        self !~ /\S/
      rescue ArgumentError
        if /invalid byte sequence/ =~ $!.message && !@_tried_to_fix_encoding_error_in_ruby_19
          self.force_encoding(Encoding::BINARY)
          @_tried_to_fix_encoding_error_in_ruby_19 = true
          retry
        else
          raise
        end
      end
    end
  end
end

And Apply this Patch

Lambda bug in Ruby 1.8

More diffs

YAML Engine

• Ruby 1.8: syck
• Ruby 1.9: psych

Compatibility

• BAD
• example
• Switch ( Not Recommanded ) :

begin
  require 'syck'
rescue LoadError
end
require 'yaml'
YAML::ENGINE.yamler = 'syck' if defined?(YAML::ENGINE)
ENV['TEST_SYCK'] = 'true'

Require in Ruby

• Ruby 1.8:

require 'config/boot'

• Ruby 1.9:

require_relative 'config/boot'

• Compatible:

require File.expand_path(File.dirname(__FILE__) + '/config/boot')

Object

Object#to_s

• Ruby 1.8:

[1,2,3,:four,[5,6], {:seven => 8}].to_s
# => "123four56seven8"

• Ruby 1.9:

[1,2,3,:four,[5,6], {:seven => 8}].to_s
# => "[1, 2, 3, :four, [5, 6], {:seven=>8}]"

• Should avoid using this method

String

String#[]

• Ruby 1.8:

'hello'[0]
# => 104

• Ruby 1.9:

'hello'[0]
# => "h"

• Compatible:

'hello'[0].chr
# => "h"

String#length

• Ruby 1.8:

'你好'.length
# => 6

• Ruby 1.9:

'你好'.length
# => 2

• Compatible:

'你好'.bytesize
# => 6

Array

Convert to Array

• Ruby 1.8: Object#to_a
• Ruby 1.9: Array()

Random choice

• Ruby 1.8:

[1, 2, 3, 4].choice

• Ruby 1.9:

[1, 2, 3, 4].sample

Array(string)

• Ruby 1.8:

Array("21312\n423424\n234234")
# => ["21312\n", "423424\n", "234234"]

• Ruby 1.9:

Array("21312\n423424\n234234")
# => ["21312\n423424\n234234"]

• This is the reason why Rails 2.3 Cookie cannot work in Ruby 1.9

Patch

unless ''.respond_to?(:each)
  module Kernel
    def Array_with_rb19_fix(element)
      if !element.nil? && element.is_a?(String)
        Array_without_rb19_fix(element.each_line)
      else
        Array_without_rb19_fix element
      end
    end

    alias_method_chain :Array, :rb19_fix
  end
end

Symbol

• Ruby 1.8: Symbol#to_i
• Ruby 1.9: could be like Symbol#object_id

Hash

Hash#select

• Ruby 1.8:

{'a' => 1, 'b' => 2}.select {|x, y| y.odd?}
# => [["a", 1]]

• Ruby 1.9:

{'a' => 1, 'b' => 2}.select {|x, y| y.odd?}
# => {"a"=>1}

Add new keys during interation

• Ruby 1.8:

h = {:a => 1, :b => 2}
h.each {|k, v| h[k.to_s[0].succ.chr.to_sym] = v + 1 }
# => {:b=>2, :e=>5, :c=>3, :d=>4, :a=>1}

h = {'a' => 1, 'b' => 2}
h.each {|k, v| h[k[0].succ.chr] = v + 1 }
# => {"c"=>3, "b"=>2, "a"=>1}

• Ruby 1.9:

RuntimeError: can't add a new key into hash during iteration

Regex

In ERB

warning: regexp match /.../n against to UTF-8 string

Date

Date.new!

Date.new0

Date.new1

Date.new2

Date.new3

Date.new(2013, 9, 21).strftime  # => "2013-09-21"
Date.new!(2013, 9, 21).strftime # => "-4707-06-07"
Date.new0(2013, 9, 21).strftime # => "-4707-06-07"
Date.new2(2013, 9, 21).strftime # => "2013-01-09"
Date.new3(2013, 9, 21).strftime # => "2013-09-21"

new!, new0, new1: Julian day

儒略日的起点订在公元前4713年（天文学上记为 -4712年）1月1日格林威治时间平午（世界时12:00），即JD 0指定为UT时间B.C.4713年1月1日12:00到UC时间B.C.4713年1月2日12:00的24小时。每一天赋予了一个唯一的数字，顺数而下，如：1996年1月1日12:00:00的儒略日是2450084。这个日期是考虑了太阳、月亮的轨道运行周期，以及当时收税的间隔而订出来的。

new2

Date.new2(2013, 256).strftime
# => "2013-09-13" # Programmers' Day!

Patch

require 'date'
require 'tzinfo'

unless DateTime.respond_to?(:new!) || DateTime.respond_to?(:new0)
  module TZInfo
    module RubyCoreSupport
      HALF_DAYS_IN_DAY = rational_new!(1, 2)

      def self.datetime_new!(ajd = 0, of = 0, sg = Date::ITALY)
        jd = ajd + of + HALF_DAYS_IN_DAY

        jd_i = jd.to_i
        jd_i -= 1 if jd < 0
        hours = (jd - jd_i) * 24
        hours_i = hours.to_i
        minutes = (hours - hours_i) * 60
        minutes_i = minutes.to_i
        seconds = (minutes - minutes_i) * 60

        DateTime.jd(jd_i, hours_i, minutes_i, seconds, of, sg)
      end
    end
  end
end

Copy from: How to upgrade a Rails 2.3 app to Ruby 1.9.3

Date.exist?

• Ruby 1.8:

  • Date.exist?
  • Date.exist1?
  • Date.exist2?
  • Date.exist3?

• Ruby 1.9:

  • Date.valid_date?
  • Date.valid_jd?
  • Date.valid_original?

ParseDate

• Ruby 1.8:

require 'parsedate'
ParseDate.parsedate "Tuesday, July 5th, 2007, 18:35:20 UTC"
# => [2007, 7, 5, 18, 35, 20, "UTC", 2]

• Ruby 1.9:

require 'date'
Date._parse(str, comp).
  values_at(:year, :mon, :mday, :hour, :min, :sec, :zone, :wday)

Time.now

• Ruby 1.8: Thu Sep 19 22:55:12 +0800 2013
• Ruby 1.9: 2013-09-19 22:55:12 +0800

BigDecimal

require 'bigdecimal'
require 'bigdecimal/util'
99.99.to_d.to_s

• Ruby 1.8:

# => '0.9999E2'

• Ruby 1.9:

# => '0.9998999999999999E2'

File

• Ruby 1.8:

require 'ftools'
File::copy(src, dst)
File::rename(old, new)

• Ruby 1.9:

require 'fileutils'
FileUtils.cp(src, dst)
File.rename(old, new)

No RDoc::Usage any more

Thanks