Class: Debride

Inherits:
MethodBasedSexpProcessor
  • Object
show all
Defined in:
lib/debride.rb

Overview

A static code analyzer that points out possible dead methods.

Constant Summary collapse

VERSION =

:nodoc:

"1.14.0"
PROJECT = 
"debride"
RAILS_DSL_METHODS =

Rails’ macro-style methods that setup method calls to happen during a rails app’s execution.

[
  :after_action,
  :around_action,
  :before_action,

  # https://api.rubyonrails.org/classes/ActiveRecord/Callbacks.html (at bottom)
  :after_commit,
  :after_create,
  :after_destroy,
  :after_find,
  :after_initialize,
  :after_rollback,
  :after_save,
  :after_touch,
  :after_update,
  :after_validation,
  :around_create,
  :around_destroy,
  :around_save,
  :around_update,
  :before_create,
  :before_destroy,
  :before_save,
  :before_update,
  :before_validation,

  # https://api.rubyonrails.org/classes/ActiveModel/Validations/ClassMethods.html#method-i-validate
  :validate,
]
RAILS_VALIDATION_METHODS =

Rails’ macro-style methods that count as method calls if their options include :if or :unless.

[
  # http://api.rubyonrails.org/classes/ActiveModel/Validations/HelperMethods.html
  :validates,
  :validates_absence_of,
  :validates_acceptance_of,
  :validates_comparison_of,
  :validates_confirmation_of,
  :validates_exclusion_of,
  :validates_format_of,
  :validates_inclusion_of,
  :validates_length_of,
  :validates_numericality_of,
  :validates_presence_of,
  :validates_size_of,
]
RAILS_MACRO_METHODS =

Rails’ macro-style methods that define methods dynamically.

[
  :belongs_to,
  :has_and_belongs_to_many,
  :has_many,
  :has_one,
  :scope,
]

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Debride

Create a new Debride instance w/ options



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# File 'lib/debride.rb', line 223

def initialize options = {}
  self.option = { :whitelist => [] }.merge options
  self.known  = Hash.new { |h,k| h[k] = Set.new }
  self.called = Set.new

  option[:parser] ||= NotRubyParser

  super()
end

Instance Attribute Details

#called ⇒ Object

A set of called method names.



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# File 'lib/debride.rb', line 213

def called
  @called
end

#known ⇒ Object

A collection of know methods, mapping method name to implementing classes.



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# File 'lib/debride.rb', line 208

def known
  @known
end

#option ⇒ Object

Command-line options.



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# File 'lib/debride.rb', line 218

def option
  @option
end

Class Method Details

.file_extensions ⇒ Object 



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# File 'lib/debride.rb', line 54

def self.file_extensions
  %w[rb rake jbuilder] + load_plugins
end

.load_plugins(proj = PROJECT) ⇒ Object 



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# File 'lib/debride.rb', line 30

def self.load_plugins proj = PROJECT
  unless defined? @@plugins then
    @@plugins = []

    task_re = /#{PROJECT}_task/o
    plugins = Gem.find_files("#{PROJECT}_*.rb").reject { |p| p =~ task_re }

    plugins.each do |plugin|
      plugin_name = File.basename(plugin, ".rb").sub(/^#{PROJECT}_/o, "")
      next if @@plugins.include? plugin_name
      begin
        load plugin
        @@plugins << plugin_name
      rescue RuntimeError, LoadError => e
        warn "error loading #{plugin.inspect}: #{e.message}. skipping..."
      end
    end
  end

  @@plugins
rescue
  []
end

.parse_options(args) ⇒ Object

Parse command line options and return a hash of parsed option values.



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# File 'lib/debride.rb', line 122

def self.parse_options args
  options = {
    :whitelist => i[
                     extended
                     included
                     inherited
                     method_added
                     method_missing
                     prepended
                    ],
    :exclude => [],
    :format => :text,
  }

  op = OptionParser.new do |opts|
    opts.banner  = "debride [options] files_or_dirs"
    opts.version = Debride::VERSION

    opts.separator ""
    opts.separator "Specific options:"
    opts.separator ""

    opts.on("-h", "--help", "Display this help.") do
      puts opts
      exit
    end

    opts.on("-e", "--exclude FILE1,FILE2,ETC", Array, "Exclude files or directories in comma-separated list.") do |list|
      options[:exclude].concat list
    end

    opts.on("-w", "--whitelist FILE", String, "Whitelist these messages.") do |s|
      options[:whitelist] = File.read(s).split(/\n+/) rescue []
    end

    opts.on("-f", "--focus PATH", String, "Only report against this path") do |s|
      unless File.exist? s then
        abort "ERROR: --focus path #{s} doesn't exist."
      end

      s = "#{s.chomp "/"}/*" if File.directory?(s)

      options[:focus] = s
    end

    opts.on("-r", "--rails", "Add some rails call conversions.") do
      options[:rails] = true
    end

    opts.on("-m", "--minimum N", Integer, "Don't show hits less than N locs.") do |n|
      options[:minimum] = n
    end

    opts.on "--legacy" "Use RubyParser for parsing." do
      require "ruby_parser"
      option[:parser] = RubyParser
    end

    opts.on("-v", "--verbose", "Verbose. Show progress processing files.") do
      options[:verbose] = true
    end

    opts.on "--json" do
      options[:format] = :json
    end

    opts.on "--yaml" do
      options[:format] = :yaml
    end
  end

  op.parse! args

  abort op.to_s if args.empty?

  options
rescue OptionParser::InvalidOption => e
  warn op.to_s
  warn ""
  warn e.message
  exit 1
end

.run(args) ⇒ Object

Top level runner for bin/debride.



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# File 'lib/debride.rb', line 61

def self.run args
  debride = Debride.new parse_options args

  extensions = self.file_extensions
  glob = "**/*.{#{extensions.join(",")}}"
  expander = PathExpander.new(args, glob)
  files = expander.process.to_a
  excl  = debride.option[:exclude]
  excl.map! { |fd| File.directory?(fd) ? "#{fd}/**/*" : fd } if excl

  files = expander.filter_files files, StringIO.new(excl.join "\n") if excl

  debride.run(files)
  debride
end

Instance Method Details

#inspect ⇒ Object 



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# File 'lib/debride.rb', line 615

def inspect
  "Debride[current=%s]" % [signature]
end

#klass_name ⇒ Object

:nodoc:



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# File 'lib/debride.rb', line 233

def klass_name # :nodoc:
  super.to_s
end

#missing ⇒ Object

Calculate the difference between known methods and called methods.



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# File 'lib/debride.rb', line 488

def missing
  whitelist_regexps = []

  option[:whitelist].each do |s|
    if s =~ /^\/.+?\/$/ then
      whitelist_regexps << Regexp.new(s[1..-2])
    else
      called << s.to_sym
    end
  end

  not_called = known.keys - called.to_a

  whitelist_regexp = Regexp.union whitelist_regexps

  not_called.reject! { |s| whitelist_regexp =~ s.to_s }

  by_class = Hash.new { |h,k| h[k] = [] }

  not_called.each do |meth|
    known[meth].each do |klass|
      by_class[klass] << meth
    end
  end

  by_class.each do |klass, meths|
    by_class[klass] = meths.sort_by(&:to_s)
  end

  by_class.sort_by { |k,v| k }
end

#missing_locations ⇒ Object 



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# File 'lib/debride.rb', line 520

def missing_locations
  focus = option[:focus]

  missing.map { |klass, meths|
    bad = meths.map { |meth|
      location =
        method_locations["#{klass}##{meth}"] ||
        method_locations["#{klass}::#{meth}"]

      if focus then
        path = location[/(.+):\d+/, 1]

        next unless File.fnmatch(focus, path)
      end

      [meth, location]
    }.compact

    [klass, bad]
  }
    .to_h
    .reject { |k,v| v.empty? }
end

#name_to_string(exp) ⇒ Object 



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# File 'lib/debride.rb', line 427

def name_to_string exp
  case exp.sexp_type
  when :const, :lit, :str then
    exp.last.to_s
  when :colon2 then
    _, lhs, rhs = exp
    "#{name_to_string lhs}::#{rhs}"
  when :colon3 then
    _, rhs = exp
    "::#{rhs}"
  when :self then # wtf?
    "self"
  else
    raise "Not handled: #{exp.inspect}"
  end
end

#plain_method_name ⇒ Object

:nodoc:



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# File 'lib/debride.rb', line 237

def plain_method_name # :nodoc:
  method_name.to_s.sub(/^::|#/, "").to_sym
end

#process_alias(exp) ⇒ Object 



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# File 'lib/debride.rb', line 383

def process_alias exp
  _, (_, lhs), (_, rhs) = exp

  record_method lhs, exp.file, exp.line

  called << rhs

  exp
end

#process_attrasgn(sexp) ⇒ Object 



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# File 'lib/debride.rb', line 241

def process_attrasgn(sexp)
  _, _, method_name, * = sexp
  method_name = method_name.last if Sexp === method_name
  called << method_name
  process_until_empty sexp
  sexp
end

#process_block_pass(exp) ⇒ Object

:nodoc:



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# File 'lib/debride.rb', line 393

def process_block_pass exp # :nodoc:
  _, name = exp

  return exp unless name

  case name.sexp_type
  when :lit then              # eg &:to_sym
    called << name.last
  else                        # eg &lvar or &method(:x)
    # do nothing, body will get processed below
  end

  process_until_empty exp

  exp
end

#process_call(sexp) ⇒ Object Also known as: process_safe_call

:nodoc:



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# File 'lib/debride.rb', line 263

def process_call sexp # :nodoc:
  _, _, method_name, * = sexp

  case method_name
  when :new then
    method_name = :initialize
  when :alias_method_chain then
    # s(:call, nil, :alias_method_chain, s(:lit, :royale), s(:lit, :cheese))
    _, _, _, (_, new_name), _ = sexp
    if option[:rails] then
      file, line = sexp.file, sexp.line
      record_method new_name, file, line
    end
  when :attr_accessor then
    # s(:call, nil, :attr_accessor, s(:lit, :a1), ...)
    _, _, _, *args = sexp
    file, line = sexp.file, sexp.line
    args.each do |(_, name)|
      if Sexp === name then
        process name
        next
      end
      record_method name, file, line
      record_method "#{name}=".to_sym, file, line
    end
  when :attr_writer then
    # s(:call, nil, :attr_writer, s(:lit, :w1), ...)
    _, _, _, *args = sexp
    file, line = sexp.file, sexp.line
    args.each do |(_, name)|
      if Sexp === name then
        process name
        next
      end
      record_method "#{name}=".to_sym, file, line
    end
  when :attr_reader then
    # s(:call, nil, :attr_reader, s(:lit, :r1), ...)
    _, _, _, *args = sexp
    file, line = sexp.file, sexp.line
    args.each do |(_, name)|
      if Sexp === name then
        process name
        next
      end
      record_method name, file, line
    end
  when :send, :public_send, :__send__, :try, :const_get then
    # s(:call, s(:const, :Seattle), :send, s(:lit, :raining?))
    _, _, _, msg_arg, * = sexp
    if Sexp === msg_arg && [:lit, :str].include?(msg_arg.sexp_type) then
      called << msg_arg.last.to_sym
    end
  when :delegate then
    # s(:call, nil, :delegate, ..., s(:hash, s(:lit, :to), s(:lit, :delegator)))
    possible_hash = sexp.last
    if Sexp === possible_hash && possible_hash.sexp_type == :hash
      possible_hash.sexp_body.each_slice(2) do |key, val|
        next unless key == s(:lit, :to)
        next unless Sexp === val

        called << val.last        if val.sexp_type == :lit
        called << val.last.to_sym if val.sexp_type == :str
      end
    end
  when :method then
    # s(:call, nil, :method, s(:lit, :foo))
    _, _, _, msg_arg, * = sexp
    if Sexp === msg_arg && [:lit, :str].include?(msg_arg.sexp_type) then
      called << msg_arg.last.to_sym
    end
  when *RAILS_DSL_METHODS, *RAILS_VALIDATION_METHODS then
    if option[:rails]
      # s(:call, nil, :before_save, s(:lit, :save_callback), s(:hash, ...))
      if RAILS_DSL_METHODS.include?(method_name)
        _, _, _, (_, new_name), * = sexp
        called << new_name if new_name
      end
      possible_hash = sexp.last
      if Sexp === possible_hash && possible_hash.sexp_type == :hash
        possible_hash.sexp_body.each_slice(2) do |key, val|
          next unless Sexp === val
          called << val.last        if val.sexp_type == :lit
          called << val.last.to_sym if val.sexp_type == :str
        end
      end
    end
  when *RAILS_MACRO_METHODS
    # s(:call, nil, :has_one, s(:lit, :has_one_relation), ...)
    _, _, _, (_, name), * = sexp

    # try to detect route scope vs model scope
    if context.include? :module or context.include? :class then
      file, line = sexp.file, sexp.line
      record_method name, file, line
    end
  when /_path$/ then
    method_name = method_name.to_s.delete_suffix("_path").to_sym if option[:rails]
  when /^deliver_/ then
    method_name = method_name.to_s.delete_prefix("deliver_").to_sym if option[:rails]
  when :alias_method then
    _, _, _, lhs, rhs = sexp

    if Sexp === lhs and Sexp === rhs then
      lhs = lhs.last
      rhs = rhs.last

      record_method lhs, sexp.file, sexp.line

      called << rhs
    end
  end

  called << method_name

  process_until_empty sexp

  sexp
end

#process_cdecl(exp) ⇒ Object

:nodoc:



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# File 'lib/debride.rb', line 410

def process_cdecl exp # :nodoc:
  _, name, val = exp

  name = name_to_string process name if Sexp === name

  process val

  signature = "#{klass_name}::#{name}"

  known[name] << klass_name

  file, line = exp.file, exp.line
  method_locations[signature] = "#{file}:#{line}"

  exp
end

#process_colon2(exp) ⇒ Object

:nodoc:



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# File 'lib/debride.rb', line 444

def process_colon2 exp # :nodoc:
  _, lhs, name = exp
  process lhs

  called << name

  exp
end

#process_colon3(exp) ⇒ Object

:nodoc:



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# File 'lib/debride.rb', line 453

def process_colon3 exp # :nodoc:
  _, name = exp

  called << name

  exp
end

#process_const(exp) ⇒ Object

:nodoc:



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# File 'lib/debride.rb', line 461

def process_const exp # :nodoc:
  _, name = exp

  called << name

  exp
end

#process_defn(sexp) ⇒ Object

:nodoc:



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# File 'lib/debride.rb', line 469

def process_defn sexp # :nodoc:
  super do
    known[plain_method_name] << klass_name
    process_until_empty sexp
  end
end

#process_defs(sexp) ⇒ Object

:nodoc:



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# File 'lib/debride.rb', line 476

def process_defs sexp # :nodoc:
  super do
    known[plain_method_name] << klass_name
    process_until_empty sexp
  end
end

#process_op_asgn2(sexp) ⇒ Object

handle &&=, ||=, etc



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# File 'lib/debride.rb', line 250

def process_op_asgn2(sexp)
  _, _, method_name, * = sexp
  called << method_name
  process_until_empty sexp
  sexp
end

#process_rb(path_or_io) ⇒ Object 



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# File 'lib/debride.rb', line 98

def process_rb path_or_io
  warn "Processing ruby: #{path_or_io}" if option[:verbose]

  case path_or_io
  when String then
    path, file = path_or_io, File.binread(path_or_io)
  when IO, StringIO then
    path, file = "(io)", path_or_io.read
  else
    raise "Unhandled type: #{path_or_io.class}:#{path_or_io.inspect}"
  end

  parser = option[:parser].new
  parser.process(file, path, option[:timeout])
rescue Racc::ParseError, RegexpError => e
  warn "Parse Error parsing #{path}. Skipping."
  warn "  #{e.message}"
rescue Timeout::Error
  warn "TIMEOUT parsing #{path}. Skipping."
end

#record_method(name, file, line) ⇒ Object 



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# File 'lib/debride.rb', line 257

def record_method name, file, line
  signature = "#{klass_name}##{name}"
  method_locations[signature] = "#{file}:#{line}"
  known[name] << klass_name
end

#report(io = $stdout) ⇒ Object

Print out a report of suspects.



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# File 'lib/debride.rb', line 547

def report io = $stdout
  focus = option[:focus]
  type  = option[:format] || :text

  send "report_#{type}", io, focus, missing_locations
end

#report_json(io, focus, missing) ⇒ Object 



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# File 'lib/debride.rb', line 591

def report_json io, focus, missing
  require "json"

  data = {
    :missing => missing
  }

  data[:focus] = focus if focus

  JSON.dump data, io
end

#report_text(io, focus, missing) ⇒ Object 



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# File 'lib/debride.rb', line 554

def report_text io, focus, missing
  if focus then
    io.puts "Focusing on #{focus}"
    io.puts
  end

  io.puts "These methods MIGHT not be called:"

  total = 0

  missing.each do |klass, meths|
    bad = meths.map { |(meth, location)|
      loc = if location then
              l0, l1 = location.split(/:/).last.scan(/\d+/).flatten.map(&:to_i)
              l1 ||= l0
              l1 - l0 + 1
            else
              1
            end

      next if option[:minimum] && loc < option[:minimum]

      total += loc

      "  %-35s %s (%d)" % [meth, location, loc]
    }.compact

    next if bad.empty?

    io.puts
    io.puts klass
    io.puts bad.join "\n"
  end
  io.puts
  io.puts "Total suspect LOC: %d" % [total]
end

#report_yaml(io, focus, missing) ⇒ Object 



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# File 'lib/debride.rb', line 603

def report_yaml io, focus, missing
  require "yaml"

  data = {
    :missing => missing
  }

  data[:focus] = focus if focus

  YAML.dump data, io
end

#run(*files) ⇒ Object 



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# File 'lib/debride.rb', line 77

def run(*files)
  files.flatten.each do |file|
    warn "Processing #{file}" if option[:verbose]

    ext = File.extname(file).sub(/^\./, "")
    ext = "rb" if ext.nil? || ext.empty?
    msg = "process_#{ext}"

    unless respond_to? msg then
      warn "  Unknown file type: #{ext}, defaulting to ruby" if option[:verbose]
      msg = "process_rb"
    end

    begin
      process send(msg, file)
    rescue RuntimeError, SyntaxError => e
      warn "  skipping #{file}: #{e.message}"
    end
  end
end