module RuboCop::Cop::CheckLineBreakable
This mixin detects collections that are safe to “break” by inserting new lines. This is useful for breaking up long lines.
Let's look at hashes as an example:
We know hash keys are safe to break across lines. We can add linebreaks into hashes on lines longer than the specified maximum. Then in further passes cops can clean up the multi-line hash. For example, say the maximum line length is as indicated below:
| v
{foo: “0000000000”, bar: “0000000000”, baz: “0000000000”}
In a LineLength autocorrection pass, a line is added before the first key that exceeds the column limit:
{foo: “0000000000”, bar: “0000000000”, baz: “0000000000”}
In a MultilineHashKeyLineBreaks pass, lines are inserted before all keys:
{foo: “0000000000”, bar: “0000000000”, baz: “0000000000”}
Then in future passes FirstHashElementLineBreak, MultilineHashBraceLayout, and TrailingCommaInHashLiteral will manipulate as well until we get:
{
foo: "0000000000", bar: "0000000000", baz: "0000000000",
}
(Note: Passes may not happen exactly in this sequence.)
Public Instance Methods
# File lib/rubocop/cop/mixin/check_line_breakable.rb, line 45 def extract_breakable_node(node, max) if node.send_type? args = process_args(node.arguments) return extract_breakable_node_from_elements(node, args, max) elsif node.array_type? || node.hash_type? return extract_breakable_node_from_elements(node, node.children, max) end nil end
Private Instance Methods
# File lib/rubocop/cop/mixin/check_line_breakable.rb, line 164 def all_on_same_line?(nodes) return true if nodes.empty? nodes.first.first_line == nodes.last.last_line end
# File lib/rubocop/cop/mixin/check_line_breakable.rb, line 185 def already_on_multiple_lines?(node) node.first_line != node.last_line end
# File lib/rubocop/cop/mixin/check_line_breakable.rb, line 98 def breakable_collection?(node, elements) # For simplicity we only want to insert breaks in normal # hashes wrapped in a set of curly braces like {foo: 1}. # That is, not a kwargs hash. For method calls, this ensures # the method call is made with parens. starts_with_bracket = node.loc.begin # If the call has a second argument, we can insert a line # break before the second argument and the rest of the # argument will get auto-formatted onto separate lines # by other cops. has_second_element = elements.length >= 2 starts_with_bracket && has_second_element end
# File lib/rubocop/cop/mixin/check_line_breakable.rb, line 152 def children_could_be_broken_up?(children) return false if all_on_same_line?(children) last_seen_line = -1 children.each do |child| return true if last_seen_line >= child.first_line last_seen_line = child.last_line end false end
# File lib/rubocop/cop/mixin/check_line_breakable.rb, line 114 def contained_by_breakable_collection_on_same_line?(node) node.each_ancestor.find do |ancestor| # Ignore ancestors on different lines. break if ancestor.first_line != node.first_line if ancestor.hash_type? || ancestor.array_type? elements = ancestor.children elsif ancestor.send_type? elements = process_args(ancestor.arguments) else next end return true if breakable_collection?(ancestor, elements) end false end
# File lib/rubocop/cop/mixin/check_line_breakable.rb, line 133 def contained_by_multiline_collection_that_could_be_broken_up?(node) node.each_ancestor.find do |ancestor| if ancestor.hash_type? || ancestor.array_type? if breakable_collection?(ancestor, ancestor.children) return children_could_be_broken_up?(ancestor.children) end end next unless ancestor.send_type? args = process_args(ancestor.arguments) if breakable_collection?(ancestor, args) return children_could_be_broken_up?(args) end end false end
# File lib/rubocop/cop/mixin/check_line_breakable.rb, line 57 def extract_breakable_node_from_elements(node, elements, max) return unless breakable_collection?(node, elements) return if safe_to_ignore?(node) line = processed_source.lines[node.first_line - 1] return if processed_source.commented?(node.loc.begin) return if line.length <= max extract_first_element_over_column_limit(node, elements, max) end
# File lib/rubocop/cop/mixin/check_line_breakable.rb, line 68 def extract_first_element_over_column_limit(node, elements, max) line = node.first_line i = 0 i += 1 while within_column_limit?(elements[i], max, line) return elements.first if i.zero? elements[i - 1] end
# File lib/rubocop/cop/mixin/check_line_breakable.rb, line 170 def process_args(args) # If there is a trailing hash arg without explicit braces, like this: # # method(1, 'key1' => value1, 'key2' => value2) # # ...then each key/value pair is treated as a method 'argument' # when determining where line breaks should appear. if (last_arg = args.last) if last_arg.hash_type? && !last_arg.braces? args = args.concat(args.pop.children) end end args end
# File lib/rubocop/cop/mixin/check_line_breakable.rb, line 81 def safe_to_ignore?(node) return true unless max return true if already_on_multiple_lines?(node) # If there's a containing breakable collection on the same # line, we let that one get broken first. In a separate pass, # this one might get broken as well, but to avoid conflicting # or redundant edits, we only mark one offense at a time. return true if contained_by_breakable_collection_on_same_line?(node) if contained_by_multiline_collection_that_could_be_broken_up?(node) return true end false end
# File lib/rubocop/cop/mixin/check_line_breakable.rb, line 77 def within_column_limit?(element, max, line) element && element.loc.column < max && element.loc.line == line end