Class: StrongMigrations::Checker

Inherits:
Object
  • Object
show all
Defined in:
lib/strong_migrations/checker.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(migration) ⇒ Checker

Returns a new instance of Checker.



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# File 'lib/strong_migrations/checker.rb', line 5

def initialize(migration)
  @migration = migration
  @new_tables = []
  @safe = false
end

Instance Attribute Details

#direction ⇒ Object

Returns the value of attribute direction.



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# File 'lib/strong_migrations/checker.rb', line 3

def direction
  @direction
end

Instance Method Details

#perform(method, *args) ⇒ Object 



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# File 'lib/strong_migrations/checker.rb', line 21

def perform(method, *args)
  unless safe?
    case method
    when :remove_column, :remove_columns, :remove_timestamps, :remove_reference, :remove_belongs_to
      columns =
        case method
        when :remove_timestamps
          ["created_at", "updated_at"]
        when :remove_column
          [args[1].to_s]
        when :remove_columns
          args[1..-1].map(&:to_s)
        else
          options = args[2] || {}
          reference = args[1]
          cols = []
          cols << "#{reference}_type" if options[:polymorphic]
          cols << "#{reference}_id"
          cols
        end

      code = "self.ignored_columns = #{columns.inspect}"

      raise_error :remove_column,
        model: args[0].to_s.classify,
        code: code,
        command: command_str(method, args),
        column_suffix: columns.size > 1 ? "s" : ""
    when :change_table
      raise_error :change_table, header: "Possibly dangerous operation"
    when :rename_table
      raise_error :rename_table
    when :rename_column
      raise_error :rename_column
    when :add_index
      table, columns, options = args
      options ||= {}

      if columns.is_a?(Array) && columns.size > 3 && !options[:unique]
        raise_error :add_index_columns, header: "Best practice"
      end
      if postgresql? && options[:algorithm] != :concurrently && !@new_tables.include?(table.to_s)
        raise_error :add_index, command: command_str("add_index", [table, columns, options.merge(algorithm: :concurrently)])
      end
    when :add_column
      table, column, type, options = args
      options ||= {}
      default = options[:default]

      if !default.nil? && !(postgresql? && postgresql_version >= 110000)

        if options[:null] == false
          options = options.except(:null)
          append = "

Then add the NOT NULL constraint.

class %{migration_name}NotNull < ActiveRecord::Migration%{migration_suffix}
  def change
#{command_str("change_column_null", [table, column, false])}
  end
end"
        end

        raise_error :add_column_default,
          add_command: command_str("add_column", [table, column, type, options.except(:default)]),
          change_command: command_str("change_column_default", [table, column, default]),
          remove_command: command_str("remove_column", [table, column]),
          code: backfill_code(table, column, default),
          append: append
      end

      if type.to_s == "json" && postgresql?
        raise_error :add_column_json
      end
    when :change_column
      table, column, type = args

      safe = false
      # assume Postgres 9.1+ since previous versions are EOL
      if postgresql? && type.to_s == "text"
        found_column = connection.columns(table).find { |c| c.name.to_s == column.to_s }
        safe = found_column && found_column.type == :string
      end
      raise_error :change_column unless safe
    when :create_table
      table, options = args
      options ||= {}

      raise_error :create_table if options[:force]

      # keep track of new tables of add_index check
      @new_tables << table.to_s
    when :add_reference, :add_belongs_to
      table, reference, options = args
      options ||= {}

      index_value = options.fetch(:index, true)
      concurrently_set = index_value.is_a?(Hash) && index_value[:algorithm] == :concurrently

      if postgresql? && index_value && !concurrently_set
        columns = options[:polymorphic] ? [:"#{reference}_type", :"#{reference}_id"] : :"#{reference}_id"

        if index_value.is_a?(Hash)
          options[:index] = options[:index].merge(algorithm: :concurrently)
        else
          options = options.merge(index: {algorithm: :concurrently})
        end

        raise_error :add_reference, command: command_str(method, [table, reference, options])
      end
    when :execute
      raise_error :execute, header: "Possibly dangerous operation"
    when :change_column_null
      table, column, null, default = args
      if !null && !default.nil?
        raise_error :change_column_null,
          code: backfill_code(table, column, default)
      end
    when :add_foreign_key
      from_table, to_table, options = args
      options ||= {}
      validate = options.fetch(:validate, true)

      if postgresql?
        if ActiveRecord::VERSION::STRING >= "5.2"
          if validate
            raise_error :add_foreign_key,
              add_foreign_key_code: command_str("add_foreign_key", [from_table, to_table, options.merge(validate: false)]),
              validate_foreign_key_code: command_str("validate_foreign_key", [from_table, to_table])
          end
        else
          # always validated before 5.2

          # fk name logic from rails
          primary_key = options[:primary_key] || "id"
          column = options[:column] || "#{to_table.to_s.singularize}_id"
          hashed_identifier = Digest::SHA256.hexdigest("#{from_table}_#{column}_fk").first(10)
          fk_name = options[:name] || "fk_rails_#{hashed_identifier}"

          raise_error :add_foreign_key,
            add_foreign_key_code: foreign_key_str("ALTER TABLE %s ADD CONSTRAINT %s FOREIGN KEY (%s) REFERENCES %s (%s) NOT VALID", [from_table, fk_name, column, to_table, primary_key]),
            validate_foreign_key_code: foreign_key_str("ALTER TABLE %s VALIDATE CONSTRAINT %s", [from_table, fk_name])
        end
      end
    end

    StrongMigrations.checks.each do |check|
      @migration.instance_exec(method, args, &check)
    end
  end

  result = yield

  if StrongMigrations.auto_analyze && direction == :up && postgresql? && method == :add_index
    connection.execute "ANALYZE VERBOSE #{connection.quote_table_name(args[0].to_s)}"
  end

  result
end

#safety_assured ⇒ Object 



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# File 'lib/strong_migrations/checker.rb', line 11

def safety_assured
  previous_value = @safe
  begin
    @safe = true
    yield
  ensure
    @safe = previous_value
  end
end