Module: PgHaMigrations::DependentObjectsChecks

Defined in:
lib/pg_ha_migrations/dependent_objects_checks.rb

Defined Under Namespace

Classes: ObjectDependency

Constant Summary collapse

ALLOWED_TYPES_OPTIONS = 
[:indexes].freeze

Instance Method Summary collapse

Instance Method Details

#dependent_objects_for_migration_method(method_name, arguments:) ⇒ Object 



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# File 'lib/pg_ha_migrations/dependent_objects_checks.rb', line 10

def dependent_objects_for_migration_method(method_name, arguments:)
  allowed_types = arguments.last.is_a?(Hash) ? arguments.last[:allow_dependent_objects] || [] : []

  if (invalid_allowed_types = allowed_types - ALLOWED_TYPES_OPTIONS).present?
    raise ArgumentError, "Received invalid entries in allow_dependent_objects: #{invalid_allowed_types.inspect}"
  end

  dependent_objects = []

  case method_name
  when :remove_column
    table_name = arguments[0]
    column_name = arguments[1]

    unless allowed_types.include?(:indexes)
      # https://www.postgresql.org/docs/current/catalog-pg-depend.html
      # deptype:
      # - 'a' (DEPENDENCY_AUTO): the dependent object should be automatically
      #   dropped if the referenced object is dropped
      indexes = ActiveRecord::Base.structs_from_sql(ObjectDependency, <<~SQL)
        SELECT
          'column' AS owner_type,
          ref_attr.attname AS owner_name,
          'index' AS dependent_type,
          dep_class.relname AS dependent_name
        FROM pg_catalog.pg_depend
        JOIN pg_catalog.pg_class ref_class ON ref_class.oid = pg_depend.refobjid
        JOIN pg_catalog.pg_attribute ref_attr ON ref_attr.attrelid = ref_class.oid
          AND ref_attr.attnum = pg_depend.refobjsubid
        JOIN pg_catalog.pg_class dep_class ON dep_class.oid = pg_depend.objid
        WHERE pg_depend.deptype = 'a'
          AND pg_depend.refclassid = 'pg_class'::regclass
          -- This doesn't currently handle table names that are duplicative across schemas.
          AND ref_class.relname = '#{PG::Connection.escape_string(table_name.to_s)}'
          AND ref_attr.attname = '#{PG::Connection.escape_string(column_name.to_s)}'
          AND pg_depend.classid = 'pg_class'::regclass
      SQL
      dependent_objects.concat(indexes)
    end
  end
end

#disallow_migration_method_if_dependent_objects!(method_name, arguments:) ⇒ Object 



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# File 'lib/pg_ha_migrations/dependent_objects_checks.rb', line 52

def disallow_migration_method_if_dependent_objects!(method_name, arguments:)
  dependent_objects = dependent_objects_for_migration_method(method_name, arguments: arguments)

  if dependent_objects.present?
    raise PgHaMigrations::UnsafeMigrationError, dependent_objects.map(&:error_text).join("; ")
  end
end