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-rw-r--r--rubocop/cop/migration/safer_boolean_column.rb94
-rw-r--r--rubocop/rubocop.rb1
-rw-r--r--spec/rubocop/cop/migration/safer_boolean_column_spec.rb85
3 files changed, 180 insertions, 0 deletions
diff --git a/rubocop/cop/migration/safer_boolean_column.rb b/rubocop/cop/migration/safer_boolean_column.rb
new file mode 100644
index 00000000000..0335c25d85d
--- /dev/null
+++ b/rubocop/cop/migration/safer_boolean_column.rb
@@ -0,0 +1,94 @@
+require_relative '../../migration_helpers'
+
+module RuboCop
+ module Cop
+ module Migration
+ # This cop requires a default value and disallows nulls for boolean
+ # columns on small tables.
+ #
+ # In general, this prevents 3-state-booleans.
+ # https://robots.thoughtbot.com/avoid-the-threestate-boolean-problem
+ #
+ # In particular, for the `application_settings` table, this ensures that
+ # upgraded installations get a proper default for the new boolean setting.
+ # A developer might otherwise mistakenly assume that a value in
+ # `ApplicationSetting.defaults` is sufficient.
+ #
+ # See https://gitlab.com/gitlab-org/gitlab-ee/issues/2750 for more
+ # information.
+ class SaferBooleanColumn < RuboCop::Cop::Cop
+ include MigrationHelpers
+
+ DEFAULT_OFFENSE = 'Boolean columns on the `%s` table should have a default. You may wish to use `add_column_with_default`.'.freeze
+ NULL_OFFENSE = 'Boolean columns on the `%s` table should disallow nulls.'.freeze
+ DEFAULT_AND_NULL_OFFENSE = 'Boolean columns on the `%s` table should have a default and should disallow nulls. You may wish to use `add_column_with_default`.'.freeze
+
+ SMALL_TABLES = %i[
+ application_settings
+ ].freeze
+
+ def_node_matcher :add_column?, <<~PATTERN
+ (send nil :add_column $...)
+ PATTERN
+
+ def on_send(node)
+ return unless in_migration?(node)
+
+ matched = add_column?(node)
+
+ return unless matched
+
+ table, _, type = matched.to_a.take(3).map(&:children).map(&:first)
+ opts = matched[3]
+
+ return unless SMALL_TABLES.include?(table) && type == :boolean
+
+ no_default = no_default?(opts)
+ nulls_allowed = nulls_allowed?(opts)
+
+ offense = if no_default && nulls_allowed
+ DEFAULT_AND_NULL_OFFENSE
+ elsif no_default
+ DEFAULT_OFFENSE
+ elsif nulls_allowed
+ NULL_OFFENSE
+ end
+
+ add_offense(node, :expression, format(offense, table)) if offense
+ end
+
+ def no_default?(opts)
+ return true unless opts
+
+ each_hash_node_pair(opts) do |key, value|
+ return value == 'nil' if key == :default
+ end
+ end
+
+ def nulls_allowed?(opts)
+ return true unless opts
+
+ each_hash_node_pair(opts) do |key, value|
+ return value != 'false' if key == :null
+ end
+ end
+
+ def each_hash_node_pair(hash_node, &block)
+ hash_node.each_node(:pair) do |pair|
+ key = hash_pair_key(pair)
+ value = hash_pair_value(pair)
+ yield(key, value)
+ end
+ end
+
+ def hash_pair_key(pair)
+ pair.children[0].children[0]
+ end
+
+ def hash_pair_value(pair)
+ pair.children[1].source
+ end
+ end
+ end
+ end
+end
diff --git a/rubocop/rubocop.rb b/rubocop/rubocop.rb
index 3fbd5b0163c..1b6e8991a17 100644
--- a/rubocop/rubocop.rb
+++ b/rubocop/rubocop.rb
@@ -13,6 +13,7 @@ require_relative 'cop/migration/add_concurrent_index'
require_relative 'cop/migration/add_index'
require_relative 'cop/migration/add_timestamps'
require_relative 'cop/migration/datetime'
+require_relative 'cop/migration/safer_boolean_column'
require_relative 'cop/migration/hash_index'
require_relative 'cop/migration/remove_concurrent_index'
require_relative 'cop/migration/remove_index'
diff --git a/spec/rubocop/cop/migration/safer_boolean_column_spec.rb b/spec/rubocop/cop/migration/safer_boolean_column_spec.rb
new file mode 100644
index 00000000000..1006594499a
--- /dev/null
+++ b/spec/rubocop/cop/migration/safer_boolean_column_spec.rb
@@ -0,0 +1,85 @@
+require 'spec_helper'
+
+require 'rubocop'
+require 'rubocop/rspec/support'
+
+require_relative '../../../../rubocop/cop/migration/safer_boolean_column'
+
+describe RuboCop::Cop::Migration::SaferBooleanColumn do
+ include CopHelper
+
+ subject(:cop) { described_class.new }
+
+ context 'in migration' do
+ before do
+ allow(cop).to receive(:in_migration?).and_return(true)
+ end
+
+ described_class::SMALL_TABLES.each do |table|
+ context "for the #{table} table" do
+ sources_and_offense = [
+ ["add_column :#{table}, :column, :boolean, default: true", 'should disallow nulls'],
+ ["add_column :#{table}, :column, :boolean, default: false", 'should disallow nulls'],
+ ["add_column :#{table}, :column, :boolean, default: nil", 'should have a default and should disallow nulls'],
+ ["add_column :#{table}, :column, :boolean, null: false", 'should have a default'],
+ ["add_column :#{table}, :column, :boolean, null: true", 'should have a default and should disallow nulls'],
+ ["add_column :#{table}, :column, :boolean", 'should have a default and should disallow nulls'],
+ ["add_column :#{table}, :column, :boolean, default: nil, null: false", 'should have a default'],
+ ["add_column :#{table}, :column, :boolean, default: nil, null: true", 'should have a default and should disallow nulls'],
+ ["add_column :#{table}, :column, :boolean, default: false, null: true", 'should disallow nulls']
+ ]
+
+ sources_and_offense.each do |source, offense|
+ context "given the source \"#{source}\"" do
+ it "registers the offense matching \"#{offense}\"" do
+ inspect_source(cop, source)
+
+ aggregate_failures do
+ expect(cop.offenses.first.message).to match(offense)
+ end
+ end
+ end
+ end
+
+ inoffensive_sources = [
+ "add_column :#{table}, :column, :boolean, default: true, null: false",
+ "add_column :#{table}, :column, :boolean, default: false, null: false"
+ ]
+
+ inoffensive_sources.each do |source|
+ context "given the source \"#{source}\"" do
+ it "registers no offense" do
+ inspect_source(cop, source)
+
+ aggregate_failures do
+ expect(cop.offenses).to be_empty
+ end
+ end
+ end
+ end
+ end
+ end
+
+ it 'registers no offense for tables not listed in SMALL_TABLES' do
+ inspect_source(cop, "add_column :large_table, :column, :boolean")
+
+ expect(cop.offenses).to be_empty
+ end
+
+ it 'registers no offense for non-boolean columns' do
+ table = described_class::SMALL_TABLES.sample
+ inspect_source(cop, "add_column :#{table}, :column, :string")
+
+ expect(cop.offenses).to be_empty
+ end
+ end
+
+ context 'outside of migration' do
+ it 'registers no offense' do
+ table = described_class::SMALL_TABLES.sample
+ inspect_source(cop, "add_column :#{table}, :column, :boolean")
+
+ expect(cop.offenses).to be_empty
+ end
+ end
+end