0_curly_braces_vs_do_end.rb

# > Note 1: Yes, the parenthesis `( )`` for the prepend call are required when
# > using this inline style. If you do not use the parenthesis it will fail
# > silently and the patch will not be applied.
# -- https://solidfoundationwebdev.com/blog/posts/writing-clean-monkey-patches-fixing-kaminari-1-0-0-argumenterror-comparison-of-fixnum-with-string-failed
#
# The code below will show what's happening in this line of code from the blog:
#
#   prepend(KaminariFix = Module.new do
#     ...
#   end)

def a(h) {a: block_given?, **h} end # This corresponds to `prepend`
def b()  {b: block_given?}      end # This corresponds to `Module.new`

# The structure of your code can be recreated like this,
# which uses parentheses to send the block to `b`
a(b()  do end) # => {:a=>false, :b=>true}

# The other way to use parentheses here would send the block to `a`
a(b()) do end  # => {:a=>true, :b=>false}

# Without parens, do/end blocks behave like the second example,
# binding to the first possible method call, which is why you added parens
a b    do end  # => {:a=>true, :b=>false}

# Curly braces are the other way to define a block
a(b()) { }     # => {:a=>true, :b=>false}
a(b()  { })    # => {:a=>false, :b=>true}

# Without parentheses, curly braces bind to the closest possible method call
a b    { }     # => {:a=>false, :b=>true}

# So in your code, any of these will work
a(b()  do end) # => {:a=>false, :b=>true}
a(b()  { })    # => {:a=>false, :b=>true}
a b    { }     # => {:a=>false, :b=>true}

1_combine_curly_braces_and_namespacing.rb

# =====  Restore the old behaviour  =====
# Undo the patch that fixes the bug: https://github.com/kaminari/kaminari/commit/01ec38a1ca2114a7ef819986304df4060571bed3
require 'kaminari/version'
Kaminari::VERSION           # => "1.0.1"
Kaminari::VERSION = '1.0.0' # => "1.0.0"

require 'kaminari'
gem_path  = $LOAD_PATH.find { |p| p =~ /kaminari-core/ }
file_path = File.join gem_path, 'kaminari/models/page_scope_methods.rb'
body      = File.read file_path
body.gsub! /(?<=default_per_page\)).to_i$/, ''
eval body


# =====  Something to paginate  =====
require 'active_record'
ActiveRecord::Base.establish_connection adapter: 'sqlite3', database: ':memory:'
ActiveRecord::Schema.verbose = false
ActiveRecord::Schema.create_table(:users) { |t| t.string :name }
User = Class.new ActiveRecord::Base
7.times { |i| User.create! name: "User#{i}" }


# =====  Before the patch  =====
# This line comes from the test to expose the bug: https://github.com/kaminari/kaminari/commit/01ec38a1ca2114a7ef819986304df4060571bed3#diff-e0776ea1e9927826ff1ece0d4b6a36d8R89
User.page(1).per('5').load.total_count rescue $! # => #<ArgumentError: comparison of Integer with String failed>


# =====  Apply the patch  =====
require 'kaminari/version'
if Kaminari::VERSION == "1.0.0"
  module Kaminari::PageScopeMethods     # module keyword ensures KaminariFix is namespaced
    prepend KaminariFix = Module.new {  # curly braces send the block to `Module.new` instead of `prepend`
      def per(num, *rest, &b)
        super(num.to_i, *rest, &b)      # this might work, at the very least it works for our example
      end
    }
  end
end


# =====  After the patch  =====
# Same line we ran in "Before the patch" but now it works
after = User.page(1).per('5').load.total_count # => 7