Module: RSpec::Hermetic::StableValue

Defined in:
lib/rspec/hermetic/stable_value.rb

Constant Summary collapse

MAX_DEPTH = 
3

Class Method Summary collapse

Class Method Details

.capture(value, depth: MAX_DEPTH, seen: {}) ⇒ Object 



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# File 'lib/rspec/hermetic/stable_value.rb', line 18

def capture(value, depth: MAX_DEPTH, seen: {})
  case value
  when nil, true, false, Symbol, Numeric
    value
  when String
    value.dup.freeze
  when Array
    return fingerprint(value) if depth <= 0

    value.map { |item| capture(item, depth: depth - 1, seen: seen) }.freeze
  when Hash
    return fingerprint(value) if depth <= 0

    value.keys.sort_by(&:to_s).to_h do |key|
      [
        capture(key, depth: depth - 1, seen: seen),
        capture(value[key], depth: depth - 1, seen: seen)
      ]
    end.freeze
  else
    object_fingerprint(value, depth, seen)
  end
end

.class_variables_for(value, depth, seen) ⇒ Object 



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# File 'lib/rspec/hermetic/stable_value.rb', line 110

def class_variables_for(value, depth, seen)
  return {} unless value.is_a?(Module)

  value.class_variables.sort_by(&:to_s).to_h do |ivar|
    [ivar.to_s, capture(value.class_variable_get(ivar), depth: depth - 1, seen: seen)]
  rescue StandardError => error
    [ivar.to_s, "#{error.class}: #{error.message}"]
  end
end

.fingerprint(value) ⇒ Object 



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# File 'lib/rspec/hermetic/stable_value.rb', line 42

def fingerprint(value)
  dumped = Marshal.dump(value)
  "#{value.class}:marshal:#{Digest::SHA256.hexdigest(dumped)}"
rescue StandardError
  normalized = value.inspect.gsub(/0x[0-9a-f]+/i, "0x...")
  "#{value.class}:inspect:#{Digest::SHA256.hexdigest(normalized)}"
end

.graph_node(object, depth) ⇒ Object 



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# File 'lib/rspec/hermetic/stable_value.rb', line 120

def graph_node(object, depth)
  {
    class: object.class.name,
    depth: depth,
    value: immediate?(object) ? object : capture(object, depth: 1)
  }
rescue StandardError => error
  {
    class: object.class.name,
    depth: depth,
    error: "#{error.class}: #{error.message}"
  }
end

.immediate?(object) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rspec/hermetic/stable_value.rb', line 134

def immediate?(object)
  object.nil? || object == true || object == false ||
    object.is_a?(Symbol) || object.is_a?(Numeric)
end

.instance_variables_for(value, depth, seen) ⇒ Object 



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# File 'lib/rspec/hermetic/stable_value.rb', line 102

def instance_variables_for(value, depth, seen)
  value.instance_variables.sort_by(&:to_s).to_h do |ivar|
    [ivar.to_s, capture(value.instance_variable_get(ivar), depth: depth - 1, seen: seen)]
  rescue StandardError => error
    [ivar.to_s, "#{error.class}: #{error.message}"]
  end
end

.object_fingerprint(value, depth, seen) ⇒ Object 



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# File 'lib/rspec/hermetic/stable_value.rb', line 83

def object_fingerprint(value, depth, seen)
  return fingerprint(value) if depth <= 0
  return "#{value.class}:cycle:#{seen[value.object_id]}" if seen.key?(value.object_id)

  seen[value.object_id] = seen.length
  dumped = Marshal.dump(value)
  "#{value.class}:marshal:#{Digest::SHA256.hexdigest(dumped)}"
rescue StandardError
  payload = {
    class: value.class.name,
    inspect: value.inspect.gsub(/0x[0-9a-f]+/i, "0x..."),
    ivars: instance_variables_for(value, depth, seen),
    class_vars: class_variables_for(value, depth, seen)
  }
  "#{value.class}:graph:#{Digest::SHA256.hexdigest(Marshal.dump(payload))}"
ensure
  seen.delete(value.object_id)
end

.reachable_graph_fingerprint(value, max_depth:, max_nodes:) ⇒ Object 



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# File 'lib/rspec/hermetic/stable_value.rb', line 50

def reachable_graph_fingerprint(value, max_depth:, max_nodes:)
  return capture(value) unless ObjectSpace.respond_to?(:reachable_objects_from)

  seen = {}
  queue = [[value, 0]]
  nodes = []

  until queue.empty? || nodes.length >= max_nodes
    object, depth = queue.shift
    next if seen[object.object_id]

    begin
      seen[object.object_id] = true
      nodes << graph_node(object, depth)
      next if depth >= max_depth

      ObjectSpace.reachable_objects_from(object).each do |child|
        next if immediate?(child)

        queue << [child, depth + 1]
      end
    rescue StandardError
      next
    end
  end

  {
    graph: Digest::SHA256.hexdigest(Marshal.dump(nodes.sort_by(&:to_s))),
    nodes: nodes.length,
    truncated: !queue.empty?
  }
end