Class: RuboCop::Cop::StatsD::PositionalArguments

Inherits:
RuboCop::Cop
  • Object
show all
Includes:
RuboCop::Cop::StatsD
Defined in:
lib/statsd/instrument/rubocop/positional_arguments.rb

Overview

This Rubocop will check for using the StatsD metric methods (e.g. StatsD.instrument) for positional argument usage, which is deprecated.

Use the following Rubocop invocation to check your project's codebase:

rubocop --require `bundle show statsd-instrument`/lib/statsd/instrument/rubocop.rb \
  --only StatsD/PositionalArguments

This cop can autocorrect some offenses it finds, but not all of them.

Constant Summary collapse

MSG = 
'Use keyword arguments for StatsD calls'
POSITIONAL_ARGUMENT_TYPES = 
Set[:int, :float, :nil]
UNKNOWN_ARGUMENT_TYPES = 
Set[:send, :const, :lvar, :splat]
REFUSED_ARGUMENT_TYPES = 
POSITIONAL_ARGUMENT_TYPES | UNKNOWN_ARGUMENT_TYPES
KEYWORD_ARGUMENT_TYPES = 
Set[:hash]
BLOCK_ARGUMENT_TYPES = 
Set[:block_pass]
ACCEPTED_ARGUMENT_TYPES = 
KEYWORD_ARGUMENT_TYPES | BLOCK_ARGUMENT_TYPES

Constants included from RuboCop::Cop::StatsD

METAPROGRAMMING_METHODS, METRIC_METHODS, SINGLETON_CONFIGURATION_METHODS

Instance Method Summary collapse

Instance Method Details

#autocorrect(node) ⇒ Object 



43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
 
# File 'lib/statsd/instrument/rubocop/positional_arguments.rb', line 43

def autocorrect(node)
  -> (corrector) do
    positional_arguments = if node.arguments.last.type == :block_pass
      node.arguments[2...node.arguments.length - 1]
    else
      node.arguments[2...node.arguments.length]
    end

    case positional_arguments[0].type
    when *UNKNOWN_ARGUMENT_TYPES
      # We don't know whether the method returns a hash, in which case it would be interpreted
      # as keyword arguments. In this case, the fix would be to add a keyword splat:
      #
      # `StatsD.instrument('foo', 1, method_call)`
      # => `StatsD.instrument('foo', 1, **method_call)`
      #
      # However, it's also possible this method returns a sample rate, in which case the fix
      # above will not do the right thing.
      #
      # `StatsD.instrument('foo', 1, SAMPLE_RATE_CONSTANT)`
      # => `StatsD.instrument('foo', 1, sample_rate: SAMPLE_RATE_CONSTANT)`
      #
      # Because of this, we will not auto-correct and let the user fix the issue manually.
      return

    when *POSITIONAL_ARGUMENT_TYPES
      value_argument = node.arguments[1]
      from = value_argument.source_range.end_pos
      to = positional_arguments.last.source_range.end_pos
      range = Parser::Source::Range.new(node.source_range.source_buffer, from, to)
      corrector.remove(range)

      keyword_arguments = []
      sample_rate = positional_arguments[0]
      if sample_rate && sample_rate.type != :nil
        keyword_arguments << "sample_rate: #{sample_rate.source}"
      end

      tags = positional_arguments[1]
      if tags && tags.type != :nil
        keyword_arguments << if tags.type == :hash && tags.source[0] != '{'
          "tags: { #{tags.source} }"
        else
          "tags: #{tags.source}"
        end
      end

      unless keyword_arguments.empty?
        corrector.insert_after(value_argument.source_range, ", #{keyword_arguments.join(', ')}")
      end
    end
  end
end

#on_send(node) ⇒ Object 



30
31
32
33
34
35
36
37
38
39
40
41
 
# File 'lib/statsd/instrument/rubocop/positional_arguments.rb', line 30

def on_send(node)
  if metric_method?(node) && node.arguments.length >= 3
    case node.arguments[2].type
    when *REFUSED_ARGUMENT_TYPES
      add_offense(node)
    when *ACCEPTED_ARGUMENT_TYPES
      nil
    else
      $stderr.puts "[StatsD/PositionalArguments] Unhandled argument type: #{node.arguments[2].type.inspect}"
    end
  end
end