class RuboCop::Cop::Style::RedundantBegin
Checks for redundant `begin` blocks.
Currently it checks for code like this:
@example
# bad def redundant begin ala bala rescue StandardError => e something end end # good def preferred ala bala rescue StandardError => e something end # bad begin do_something end # good do_something # bad # When using Ruby 2.5 or later. do_something do begin something rescue => ex anything end end # good # In Ruby 2.5 or later, you can omit `begin` in `do-end` block. do_something do something rescue => ex anything end # good # Stabby lambdas don't support implicit `begin` in `do-end` blocks. -> do begin foo rescue Bar baz end end
Constants
- MSG
Public Instance Methods
on_block(node)
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# File lib/rubocop/cop/style/redundant_begin.rb, line 84 def on_block(node) return if target_ruby_version < 2.5 return if node.send_node.lambda_literal? return if node.braces? return unless node.body&.kwbegin_type? register_offense(node.body) end
Also aliased as: on_numblock
on_def(node)
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# File lib/rubocop/cop/style/redundant_begin.rb, line 76 def on_def(node) return unless node.body&.kwbegin_type? return if node.endless? && !node.body.children.one? register_offense(node.body) end
Also aliased as: on_defs
on_kwbegin(node)
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# File lib/rubocop/cop/style/redundant_begin.rb, line 95 def on_kwbegin(node) return unless (target_node = offensive_kwbegins(node).to_a.last) register_offense(target_node) end
Private Instance Methods
allowable_kwbegin?(node)
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# File lib/rubocop/cop/style/redundant_begin.rb, line 103 def allowable_kwbegin?(node) empty_begin?(node) || begin_block_has_multiline_statements?(node) || contain_rescue_or_ensure?(node) || valid_context_using_only_begin?(node) end
begin_block_has_multiline_statements?(node)
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# File lib/rubocop/cop/style/redundant_begin.rb, line 169 def begin_block_has_multiline_statements?(node) node.children.count >= 2 end
condition_range(node)
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# File lib/rubocop/cop/style/redundant_begin.rb, line 161 def condition_range(node) range_between(node.loc.keyword.begin_pos, node.condition.source_range.end_pos) end
contain_rescue_or_ensure?(node)
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# File lib/rubocop/cop/style/redundant_begin.rb, line 173 def contain_rescue_or_ensure?(node) first_child = node.children.first first_child.rescue_type? || first_child.ensure_type? end
correct_modifier_form_after_multiline_begin_block(corrector, node)
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# File lib/rubocop/cop/style/redundant_begin.rb, line 154 def correct_modifier_form_after_multiline_begin_block(corrector, node) condition_range = condition_range(node.parent) corrector.insert_after(node.children.first, " #{condition_range.source}") corrector.remove(range_by_whole_lines(condition_range, include_final_newline: true)) end
empty_begin?(node)
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# File lib/rubocop/cop/style/redundant_begin.rb, line 165 def empty_begin?(node) node.children.empty? end
register_offense(node)
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# File lib/rubocop/cop/style/redundant_begin.rb, line 110 def register_offense(node) offense_range = node.loc.begin add_offense(offense_range) do |corrector| if node.parent&.assignment? replace_begin_with_statement(corrector, offense_range, node) else corrector.remove(offense_range) end if use_modifier_form_after_multiline_begin_block?(node) correct_modifier_form_after_multiline_begin_block(corrector, node) end corrector.remove(node.loc.end) end end
replace_begin_with_statement(corrector, offense_range, node)
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# File lib/rubocop/cop/style/redundant_begin.rb, line 127 def replace_begin_with_statement(corrector, offense_range, node) first_child = node.children.first source = first_child.source source = "(#{source})" if first_child.if_type? && first_child.modifier_form? corrector.replace(offense_range, source) corrector.remove(range_between(offense_range.end_pos, first_child.source_range.end_pos)) restore_removed_comments(corrector, offense_range, node, first_child) end
restore_removed_comments(corrector, offense_range, node, first_child)
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Restore comments that occur between “begin” and “first_child”. These comments will be moved to above the assignment line.
# File lib/rubocop/cop/style/redundant_begin.rb, line 141 def restore_removed_comments(corrector, offense_range, node, first_child) comments_range = range_between(offense_range.end_pos, first_child.source_range.begin_pos) comments = comments_range.source corrector.insert_before(node.parent, comments) unless comments.blank? end
use_modifier_form_after_multiline_begin_block?(node)
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# File lib/rubocop/cop/style/redundant_begin.rb, line 148 def use_modifier_form_after_multiline_begin_block?(node) return unless (parent = node.parent) node.multiline? && parent.if_type? && parent.modifier_form? end
valid_begin_assignment?(node)
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# File lib/rubocop/cop/style/redundant_begin.rb, line 186 def valid_begin_assignment?(node) node.parent&.assignment? && !node.children.one? end
valid_context_using_only_begin?(node)
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# File lib/rubocop/cop/style/redundant_begin.rb, line 179 def valid_context_using_only_begin?(node) parent = node.parent valid_begin_assignment?(node) || parent&.post_condition_loop? || parent&.send_type? || parent&.operator_keyword? end