class RuboCop::Cop::Style::Alias
This cop enforces the use of either `#alias` or `#alias_method` depending on configuration. It also flags uses of `alias :symbol` rather than `alias bareword`.
@example
# EnforcedStyle: prefer_alias # good alias bar foo # bad alias_method :bar, :foo alias :bar :foo
@example
# EnforcedStyle: prefer_alias_method # good alias_method :bar, :foo # bad alias bar foo
Constants
- MSG_ALIAS
- MSG_ALIAS_METHOD
- MSG_SYMBOL_ARGS
Public Instance Methods
on_alias(node)
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# File lib/rubocop/cop/style/alias.rb, line 44 def on_alias(node) return unless alias_method_possible?(node) if scope_type(node) == :dynamic || style == :prefer_alias_method add_offense(node, location: :keyword, message: MSG_ALIAS) elsif node.children.none? { |arg| bareword?(arg) } add_offense_for_args(node) end end
on_send(node)
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# File lib/rubocop/cop/style/alias.rb, line 36 def on_send(node) return unless node.command?(:alias_method) return unless style == :prefer_alias && alias_keyword_possible?(node) msg = format(MSG_ALIAS_METHOD, lexical_scope_type(node)) add_offense(node, location: :selector, message: msg) end
Private Instance Methods
add_offense_for_args(node)
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# File lib/rubocop/cop/style/alias.rb, line 75 def add_offense_for_args(node) existing_args = node.children.map(&:source).join(' ') preferred_args = node.children.map { |a| a.source[1..-1] }.join(' ') arg_ranges = node.children.map(&:source_range) msg = format(MSG_SYMBOL_ARGS, preferred_args, existing_args) add_offense(node, location: arg_ranges.reduce(&:join), message: msg) end
alias_keyword_possible?(node)
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# File lib/rubocop/cop/style/alias.rb, line 56 def alias_keyword_possible?(node) scope_type(node) != :dynamic && node.arguments.all?(&:sym_type?) end
alias_method_possible?(node)
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# File lib/rubocop/cop/style/alias.rb, line 60 def alias_method_possible?(node) scope_type(node) != :instance_eval && node.children.none?(&:gvar_type?) end
autocorrect(node)
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# File lib/rubocop/cop/style/alias.rb, line 65 def autocorrect(node) if node.send_type? correct_alias_method_to_alias(node) elsif scope_type(node) == :dynamic || style == :prefer_alias_method correct_alias_to_alias_method(node) else correct_alias_with_symbol_args(node) end end
bareword?(sym_node)
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# File lib/rubocop/cop/style/alias.rb, line 111 def bareword?(sym_node) !sym_node.source.start_with?(':') end
correct_alias_method_to_alias(send_node)
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# File lib/rubocop/cop/style/alias.rb, line 115 def correct_alias_method_to_alias(send_node) lambda do |corrector| new, old = *send_node.arguments replacement = "alias #{new.children.first} #{old.children.first}" corrector.replace(send_node.source_range, replacement) end end
correct_alias_to_alias_method(node)
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# File lib/rubocop/cop/style/alias.rb, line 123 def correct_alias_to_alias_method(node) lambda do |corrector| new, old = *node replacement = "alias_method :#{new.children.first}, " \ ":#{old.children.first}" corrector.replace(node.source_range, replacement) end end
correct_alias_with_symbol_args(node)
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# File lib/rubocop/cop/style/alias.rb, line 132 def correct_alias_with_symbol_args(node) lambda do |corrector| new, old = *node corrector.replace(new.source_range, new.children.first.to_s) corrector.replace(old.source_range, old.children.first.to_s) end end
lexical_scope_type(node)
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# File lib/rubocop/cop/style/alias.rb, line 104 def lexical_scope_type(node) node.each_ancestor(:class, :module) do |ancestor| return ancestor.class_type? ? 'in a class body' : 'in a module body' end 'at the top level' end
scope_type(node)
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In this expression, will `self` be the same as the innermost enclosing class or module block (:lexical)? Or will it be something else (:dynamic)? If we're in an instance_eval block, return that.
# File lib/rubocop/cop/style/alias.rb, line 87 def scope_type(node) while (parent = node.parent) case parent.type when :class, :module return :lexical when :def, :defs return :dynamic when :block return :instance_eval if parent.method_name == :instance_eval return :dynamic end node = parent end :lexical end