Method: Refinement::Changeset.parse_raw_diff

Defined in:
lib/refinement/changeset.rb

.parse_raw_diff(diff, repository:, base_revision:) ⇒ Array<FileModification>

Parses the raw diff into FileModification objects

Parameters:

  • diff (String) —

    a diff generated by ‘git diff –raw -z`

  • repository (Pathname) —

    the path to the repository

  • base_revision (String) —

    the base revision the diff was constructed agains

Returns:



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# File 'lib/refinement/changeset.rb', line 163

def self.parse_raw_diff(diff, repository:, base_revision:)
  # since we're null separating the chunks (to avoid dealing with path escaping) we have to reconstruct
  # the chunks into individual diff entries. entries always start with a colon so we can use that to signal if
  # we're on a new entry
  parsed_lines = diff.split("\0").each_with_object([]) do |chunk, lines|
    lines << [] if chunk.start_with?(':')
    lines.last << chunk
  end

  parsed_lines.map do |split_line|
    # change chunk (letter + optional similarity percentage) will always be the last part of first line chunk
    change_chunk = split_line[0].split(/\s/).last

    new_path = Pathname(split_line[2]).freeze if split_line[2]
    old_path = Pathname(split_line[1]).freeze
    prior_path = old_path if new_path
    # new path if one exists, else existing path. new path only exists for rename and copy
    changed_path = new_path || old_path

    change_character = change_chunk[0]
    # returns 0 when a similarity percentage isn't specified by git.
    _similarity = change_chunk[1..3].to_i

    FileModification.new(
      path: changed_path,
      type: CHANGE_CHARACTERS[change_character],
      prior_path: prior_path,
      contents_reader: -> { repo.join(changed_path).read },
      prior_contents_reader: lambda {
        git!('show', "#{base_revision}:#{prior_path || changed_path}", chdir: repository)
      }
    )
  end
end