Class: Ruby::Merge::RescueSemantics

Inherits:
Object
  • Object
show all
Defined in:
lib/ruby/merge/rescue_semantics.rb

Overview

Normalizes rescue clause ordering while preserving source-defined exception hierarchies and Ruby's broader-handler semantics. rubocop:disable Metrics/AbcSize, Metrics/ClassLength, Metrics/CyclomaticComplexity rubocop:disable Metrics/MethodLength, Metrics/PerceivedComplexity

Instance Method Summary collapse

Constructor Details

#initialize(source_defined_exception_definitions: []) ⇒ RescueSemantics

Returns a new instance of RescueSemantics.



10
11
12
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 10

def initialize(source_defined_exception_definitions: [])
  @source_defined_exception_definitions = source_defined_exception_definitions
end

Instance Method Details

#broad_rescue_clause_type?(clause_type) ⇒ Boolean

Returns:

  • (Boolean) 


90
91
92
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 90

def broad_rescue_clause_type?(clause_type)
  rescue_clause_type?(clause_type) && clause_type[1] == [:standard_error]
end

#broader_rescue_clause_type_than?(left_clause_type, right_clause_type) ⇒ Boolean

Returns:

  • (Boolean) 


209
210
211
212
213
214
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 209

def broader_rescue_clause_type_than?(left_clause_type, right_clause_type)
  return false unless rescue_clause_type?(left_clause_type) && rescue_clause_type?(right_clause_type)

  rescue_clause_covers?(left_clause_type, right_clause_type) &&
    !rescue_clause_covers?(right_clause_type, left_clause_type)
end

#canonicalize_begin_clause_kind_order(clause_types) ⇒ Object 



71
72
73
74
75
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 71

def canonicalize_begin_clause_kind_order(clause_types)
  clause_types.each_with_index
              .sort_by { |(clause_type, index)| [clause_kind_sort_key(clause_type), index] }
              .map(&:first)
end

#canonicalize_rescue_clause_order(clause_types) ⇒ Object 



37
38
39
40
41
42
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
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 37

def canonicalize_rescue_clause_order(clause_types)
  rescue_clause_types = clause_types.select { |clause_type| rescue_clause_type?(clause_type) }
  return clause_types if rescue_clause_types.length < 2

  ordered_rescue_types = rescue_clause_types.dup

  if rescue_clause_types.any? { |clause_type| broad_rescue_clause_type?(clause_type) } &&
     rescue_clause_types.any? { |clause_type| !broad_rescue_clause_type?(clause_type) }
    specific_rescue_types = ordered_rescue_types.reject { |clause_type| broad_rescue_clause_type?(clause_type) }
    broad_rescue_types = ordered_rescue_types.select { |clause_type| broad_rescue_clause_type?(clause_type) }
    ordered_rescue_types = specific_rescue_types + broad_rescue_types
  end

  loop do
    swapped = false

    (0...(ordered_rescue_types.length - 1)).each do |index|
      left_clause_type = ordered_rescue_types[index]
      right_clause_type = ordered_rescue_types[index + 1]
      next unless broader_rescue_clause_type_than?(left_clause_type, right_clause_type)

      ordered_rescue_types[index] = right_clause_type
      ordered_rescue_types[index + 1] = left_clause_type
      swapped = true
    end

    break unless swapped
  end

  clause_types.map do |clause_type|
    rescue_clause_type?(clause_type) ? ordered_rescue_types.shift : clause_type
  end
end

#clause_kind_sort_key(clause_type) ⇒ Object 



94
95
96
97
98
99
100
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 94

def clause_kind_sort_key(clause_type)
  return 0 if rescue_clause_type?(clause_type)
  return 1 if clause_type == :else_clause
  return 2 if clause_type == :ensure_clause

  3
end

#exception_constant_covers?(covering_constant, covered_constant) ⇒ Boolean

Returns:

  • (Boolean) 


163
164
165
166
167
168
169
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 163

def exception_constant_covers?(covering_constant, covered_constant)
  return true if covering_constant == covered_constant

  covered_constant < covering_constant
rescue StandardError
  false
end

#exception_name_covers?(covering_name, covered_name) ⇒ Boolean

Returns:

  • (Boolean) 


184
185
186
187
188
189
190
191
192
193
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 184

def exception_name_covers?(covering_name, covered_name)
  covering_constant = resolve_exception_constant(covering_name)
  covered_constant = resolve_exception_constant(covered_name)

  if covering_constant && covered_constant
    exception_constant_covers?(covering_constant, covered_constant)
  else
    source_defined_exception_covers?(covering_name, covered_name)
  end
end

#merge_ordered_clause_types(primary_types, secondary_types) ⇒ Object 



14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 14

def merge_ordered_clause_types(primary_types, secondary_types)
  ordered = primary_types.dup

  secondary_types.each_with_index do |clause_type, secondary_index|
    next if ordered.include?(clause_type)

    previous_shared = secondary_types[0...secondary_index].reverse.find { |type| ordered.include?(type) }
    next_shared = secondary_types[(secondary_index + 1)..]&.find { |type| ordered.include?(type) }

    if previous_shared
      insert_at = ordered.index(previous_shared) + 1
      ordered.insert(insert_at, clause_type)
    elsif next_shared
      insert_at = ordered.index(next_shared)
      ordered.insert(insert_at, clause_type)
    else
      ordered << clause_type
    end
  end

  ordered
end

#normalize_exception_name(exception_name) ⇒ Object 



102
103
104
105
106
107
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 102

def normalize_exception_name(exception_name)
  return 'StandardError' if exception_name == :standard_error

  name = exception_name.to_s.sub(/\A::/, '')
  name.empty? ? nil : name
end

#qualify_source_constant_name(constant_name, namespace = nil) ⇒ Object 



109
110
111
112
113
114
115
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 109

def qualify_source_constant_name(constant_name, namespace = nil)
  normalized_name = normalize_exception_name(constant_name)
  return if normalized_name.nil?
  return normalized_name if constant_name.to_s.start_with?('::') || namespace.nil? || namespace.empty?

  "#{namespace}::#{normalized_name}"
end

#rescue_clause_covers?(covering_clause_type, covered_clause_type) ⇒ Boolean

Returns:

  • (Boolean) 


195
196
197
198
199
200
201
202
203
204
205
206
207
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 195

def rescue_clause_covers?(covering_clause_type, covered_clause_type)
  return false unless rescue_clause_type?(covering_clause_type) && rescue_clause_type?(covered_clause_type)

  covering_names = rescue_clause_exception_names(covering_clause_type)
  covered_names = rescue_clause_exception_names(covered_clause_type)
  return false if covering_names.empty? || covered_names.empty?

  covered_names.all? do |covered_name|
    covering_names.any? do |covering_name|
      exception_name_covers?(covering_name, covered_name)
    end
  end
end

#rescue_clause_exception_constants(clause_type) ⇒ Object 



157
158
159
160
161
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 157

def rescue_clause_exception_constants(clause_type)
  rescue_clause_exception_names(clause_type).filter_map do |exception_name|
    resolve_exception_constant(exception_name)
  end
end

#rescue_clause_exception_names(clause_type) ⇒ Object 



151
152
153
154
155
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 151

def rescue_clause_exception_names(clause_type)
  return [] unless rescue_clause_type?(clause_type)

  Array(clause_type[1]).filter_map { |exception_name| normalize_exception_name(exception_name) }
end

#rescue_clause_signature(exception_names) ⇒ Object 



77
78
79
80
81
82
83
84
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 77

def rescue_clause_signature(exception_names)
  normalized_exceptions = Array(exception_names).filter_map { |exception| normalize_exception_name(exception) }
  if normalized_exceptions.empty? || normalized_exceptions == ['StandardError']
    [:standard_error]
  else
    normalized_exceptions.sort
  end
end

#rescue_clause_type?(clause_type) ⇒ Boolean

Returns:

  • (Boolean) 


86
87
88
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 86

def rescue_clause_type?(clause_type)
  clause_type.is_a?(Array) && clause_type.first == :rescue_clause
end

#resolve_exception_constant(exception_name) ⇒ Object 



142
143
144
145
146
147
148
149
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 142

def resolve_exception_constant(exception_name)
  return ::StandardError if exception_name == :standard_error
  return unless exception_name.is_a?(String) && !exception_name.empty?

  exception_name.split('::').reject(&:empty?).inject(Object) { |scope, const_name| scope.const_get(const_name) }
rescue NameError
  nil
end

#source_defined_exception_covers?(covering_name, covered_name) ⇒ Boolean

Returns:

  • (Boolean) 


171
172
173
174
175
176
177
178
179
180
181
182
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 171

def source_defined_exception_covers?(covering_name, covered_name)
  normalized_covering = normalize_exception_name(covering_name)
  current_name = normalize_exception_name(covered_name)
  return false if normalized_covering.nil? || current_name.nil?
  return true if normalized_covering == current_name

  while (current_name = source_defined_exception_hierarchy[current_name])
    return true if current_name == normalized_covering
  end

  false
end

#source_defined_exception_hierarchy ⇒ Object 



117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
 
# File 'lib/ruby/merge/rescue_semantics.rb', line 117

def source_defined_exception_hierarchy
  @source_defined_exception_hierarchy ||= begin
    definitions = @source_defined_exception_definitions
    defined_names = definitions.map { |definition| definition[:name] }.compact.to_set

    definitions.each_with_object({}) do |definition, hierarchy|
      next unless definition[:name] && definition[:superclass]

      superclass_name = if definition[:superclass].to_s.start_with?('::')
                          normalize_exception_name(definition[:superclass])
                        else
                          candidate_name = qualify_source_constant_name(definition[:superclass],
                                                                        definition[:namespace])
                          if defined_names.include?(candidate_name)
                            candidate_name
                          else
                            normalize_exception_name(definition[:superclass])
                          end
                        end

      hierarchy[definition[:name]] ||= superclass_name if superclass_name
    end
  end
end