Module: Ruby::Merge::MagicCommentSupport

Defined in:
lib/ruby/merge/magic_comment_support.rb

Overview

Ruby magic comment detection and file-header prefix handling. Header scanning intentionally preserves source order and duplicate entries because those details affect comment ownership during reconstruction. rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/MethodLength

Constant Summary collapse

MAGIC_COMMENT_PATTERNS = 
{
  frozen_string_literal: /^frozen_string_literal:\s*(true|false)$/i,
  encoding: /^(encoding|coding):\s*\S+$/i,
  warn_indent: /^warn_indent:\s*(true|false)$/i,
  shareable_constant_value: /^shareable_constant_value:\s*\S+$/i
}.freeze

Class Method Summary collapse

Class Method Details

.comment_only_prefix_info(lines) ⇒ Object 



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# File 'lib/ruby/merge/magic_comment_support.rb', line 29

def comment_only_prefix_info(lines)
  entries = []
  suppressed_line_nums = Set.new
  duplicate_magic_line_nums = Set.new

  if shebang_line?(lines.first)
    entries << { line_num: 1, text: lines.first.to_s, kind: :shebang }
    suppressed_line_nums << 1
  end

  header_magic_types = header_magic_comment_types_for_lines(lines)
  seen_magic_types = Set.new

  header_magic_types.keys.sort.each do |line_num|
    magic_type = header_magic_types[line_num]
    suppressed_line_nums << line_num
    entries << { line_num: line_num, text: lines[line_num - 1].to_s.chomp, kind: :magic }

    if seen_magic_types.include?(magic_type)
      duplicate_magic_line_nums << line_num
    else
      seen_magic_types << magic_type
    end
  end

  if header_magic_types.any?
    blank_line_num = header_magic_types.keys.max + 1

    while blank_line_num <= lines.length && lines[blank_line_num - 1].to_s.rstrip.empty?
      entries << { line_num: blank_line_num, text: lines[blank_line_num - 1].to_s, kind: :blank }
      suppressed_line_nums << blank_line_num
      blank_line_num += 1
    end
  end

  {
    entries: entries,
    suppressed_line_nums: suppressed_line_nums,
    duplicate_magic_line_nums: duplicate_magic_line_nums,
    header_magic_comment_types: header_magic_types
  }
end

.header_magic_comment_types_for_lines(lines) ⇒ Object 



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# File 'lib/ruby/merge/magic_comment_support.rb', line 72

def header_magic_comment_types_for_lines(lines)
  types = {}
  index = shebang_line?(lines.first) ? 1 : 0
  previous_line_num = shebang_line?(lines.first) ? 1 : nil

  while index < lines.length
    line_num = index + 1
    stripped = lines[index].to_s.rstrip
    break if stripped.empty?

    expected_line_num = previous_line_num ? previous_line_num + 1 : 1
    break unless line_num == expected_line_num

    magic_type = magic_comment_type_for_text(stripped)
    break unless magic_type

    types[line_num] = magic_type
    previous_line_num = line_num
    index += 1
  end

  types
end

.magic_comment_type_for_text(text) ⇒ Object 



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# File 'lib/ruby/merge/magic_comment_support.rb', line 19

def magic_comment_type_for_text(text)
  stripped = DocCommentSupport.normalize_comment_content(text)

  MAGIC_COMMENT_PATTERNS.each do |type, pattern|
    return type if stripped.match?(pattern)
  end

  nil
end

.prefix_comment_line_numbers_for_comments(comments) ⇒ Object 



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# File 'lib/ruby/merge/magic_comment_support.rb', line 96

def prefix_comment_line_numbers_for_comments(comments)
  prefix_line_nums = Set.new
  previous_line_num = nil
  index = 0

  if shebang_comment?(comments.first)
    prefix_line_nums << 1
    previous_line_num = 1
    index = 1
  end

  while index < comments.length
    comment = comments[index]
    line_num = comment.location.start_line
    expected_line_num = previous_line_num ? previous_line_num + 1 : 1
    break unless line_num == expected_line_num
    break unless magic_comment_type_for_text(comment.slice)

    prefix_line_nums << line_num
    previous_line_num = line_num
    index += 1
  end

  prefix_line_nums
end

.shebang_comment?(comment) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ruby/merge/magic_comment_support.rb', line 126

def shebang_comment?(comment)
  comment&.slice&.start_with?('#!')
end

.shebang_line?(line) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ruby/merge/magic_comment_support.rb', line 122

def shebang_line?(line)
  line.to_s.start_with?('#!')
end