class RuboCop::Cop::Style::InfiniteLoop
end
work
loop do
# good
end
work
while true
# bad
@example
other infinite loops, ‘Kernel#loop` silently rescues that and returns `nil`.
apply if the body might raise a `StopIteration` exception; contrary to
This cop is marked as unsafe as the rule does not necessarily
Use `Kernel#loop` for infinite loops.
def self.joining_forces
def self.joining_forces VariableForce end
def after_leaving_scope(scope, _variable_table)
def after_leaving_scope(scope, _variable_table) @variables ||= [] @variables.concat(scope.variables.values) end
def assigned_before_loop?(var, range)
def assigned_before_loop?(var, range) b = range.begin_pos var.assignments.any? { |a| a.node.source_range.end_pos < b } end
def assigned_inside_loop?(var, range)
def assigned_inside_loop?(var, range) var.assignments.any? { |a| range.contains?(a.node.source_range) } end
def autocorrect(corrector, node)
def autocorrect(corrector, node) if node.while_post_type? || node.until_post_type? replace_begin_end_with_modifier(corrector, node) elsif node.modifier_form? replace_source(corrector, node.source_range, modifier_replacement(node)) else replace_source(corrector, non_modifier_range(node), 'loop do') end end
def configured_indent
def configured_indent ' ' * config.for_cop('Layout/IndentationWidth')['Width'] end
def modifier_replacement(node)
def modifier_replacement(node) body = node.body if node.single_line? "loop { #{body.source} }" else indentation = body.source_range.source_line[LEADING_SPACE] ['loop do', body.source.gsub(/^/, configured_indent), 'end'].join("\n#{indentation}") end end
def non_modifier_range(node)
def non_modifier_range(node) start_range = node.loc.keyword.begin end_range = if node.do? node.loc.begin.end else node.condition.source_range.end end start_range.join(end_range) end
def on_until(node)
def on_until(node) while_or_until(node) if node.condition.falsey_literal? end
def on_while(node)
def on_while(node) while_or_until(node) if node.condition.truthy_literal? end
def referenced_after_loop?(var, range)
def referenced_after_loop?(var, range) e = range.end_pos var.references.any? { |r| r.node.source_range.begin_pos > e } end
def replace_begin_end_with_modifier(corrector, node)
def replace_begin_end_with_modifier(corrector, node) corrector.replace(node.body.loc.begin, 'loop do') corrector.remove(node.body.loc.end.end.join(node.source_range.end)) end
def replace_source(corrector, range, replacement)
def replace_source(corrector, range, replacement) corrector.replace(range, replacement) end
def while_or_until(node)
def while_or_until(node) range = node.source_range # Not every `while true` and `until false` can be turned into a # `loop do` without further modification. The reason is that a # variable that's introduced inside a while/until loop is in scope # outside of that loop too, but a variable that's assigned for the # first time inside a block cannot be accessed after the block. In # those more complicated cases we don't report an offense. return if @variables.any? do |var| assigned_inside_loop?(var, range) && !assigned_before_loop?(var, range) && referenced_after_loop?(var, range) end add_offense(node.loc.keyword) do |corrector| autocorrect(corrector, node) end end