Module: Permittable::ColumnGuard

Defined in:
lib/permittable/column_guard.rb

Overview

Schema validation behind the drift guard. When the schema is unreachable — no database yet (db:create, a fresh db:migrate, assets:precompile, CI bootstrap) or the table not yet migrated — the check is skipped and false is returned instead of raising, so controller classes stay loadable. A missing column with a reachable schema still raises: the rescue is scoped to ActiveRecord::ActiveRecordError precisely so real bugs (NameError from a typo etc.) keep surfacing. Skipping is self-healing: once the migration runs and classes reload, validation happens for real.

Class Method Summary collapse

Class Method Details

.column_migration_hint(klass, field, types) ⇒ Object 



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# File 'lib/permittable/column_guard.rb', line 31

def column_migration_hint(klass, field, types)
  type = types.is_a?(Hash) ? types[field.to_sym] : types
  column = [field, type].compact.join(":")
  " Add it with: bin/rails generate migration " \
    "Add#{field.to_s.camelize}To#{klass.table_name.to_s.camelize} #{column}"
end

.ensure_columns_on!(label, klass, *fields, types: nil) ⇒ Object

types: teaches the error message: a Symbol/String applies to every listed field, a Hash maps field => type. The raised ArgumentError then appends a ready-to-paste migration command.



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# File 'lib/permittable/column_guard.rb', line 18

def ensure_columns_on!(label, klass, *fields, types: nil)
  return false unless schema_reachable?(klass)

  fields.flatten.compact.each do |field|
    next if klass.column_names.include?(field.to_s)

    raise ArgumentError,
          "#{label}: '#{field}' does not exist in the database (table: #{klass.table_name})." \
          "#{column_migration_hint(klass, field, types)}"
  end
  true
end

.schema_reachable?(klass) ⇒ Boolean

True when the class's table can actually be inspected. Connection errors (ConnectionNotEstablished, NoDatabaseError, adapter errors) all inherit from ActiveRecord::ActiveRecordError; the defined? guard keeps this gem loadable without activerecord (a host without it cannot pass model: anyway).

Returns:

  • (Boolean) 


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# File 'lib/permittable/column_guard.rb', line 43

def schema_reachable?(klass)
  klass.table_exists?
rescue StandardError => e
  raise unless defined?(ActiveRecord::ActiveRecordError) && e.is_a?(ActiveRecord::ActiveRecordError)

  false
end