26721499467

Committed 31 May 2026 06:56PM UTC coverage: 96.838% (-0.02%) from 96.861%

Build # 26721499467

Build Type

Pull #2752

github

Committed by

ericproulx

Commit Message

Skip per-request instrumentation work when no subscribers are listening

Grape fires up to six ActiveSupport::Notifications.instrument calls per
request (endpoint run / render / run_validators / run_filters and
format_response). Each builds a payload Hash and enters the notification
machinery on every request, even when nothing is subscribed to the event.

Guard each emission behind ActiveSupport::Notifications.notifier.listening?
via a small private instrument_<event> method on the owning class. With no
subscriber the block runs directly, skipping the payload Hash and the
instrument dispatch; the block is forwarded anonymously so nothing extra is
allocated unless a subscriber is present. Behaviour is unchanged when a
subscriber exists - same events, same payloads.

Saves one Hash allocation per emitted event (-6 allocations/request on an
endpoint with before/after filters and params), ~+4.6% median throughput
under YJIT on that endpoint; scales with events emitted per request.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Pull Request Pull Request #2752: Skip per-request instrumentation work when no subscribers are listening

Coverage Stats

1112 of 1203 branches covered (92.44%)

Branch coverage included in aggregate %.

19 of 20 new or added lines in 2 files covered. (95.0%)

1 existing line in 1 file now uncovered.

3543 of 3604 relevant lines covered (98.31%)

23213.33 hits per line

Source File
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96.15

/lib/grape/exceptions/validation_errors.rb

# frozen_string_literal: true

module Grape
  module Exceptions
    class ValidationErrors < Base
      include Enumerable

      attr_reader :errors

      def initialize(exceptions: [], headers: {})
        @errors = exceptions.flat_map(&:errors).group_by(&:params)
        super(message: full_messages.join(', '), status: 400, headers:)
      end

      def each
        errors.each_pair do |attribute, errors|
          errors.each do |error|
            yield attribute, error
          end
        end
      end

      def as_json(**_opts)
        errors.map do |k, v|
          {
            params: k,
            messages: v.map(&:to_s)
          }
        end
      end

      def to_json(*_opts)
        as_json.to_json
      end

      def full_messages
        messages = map do |attributes, error|
          translate(
            :format,
            scope: 'grape.errors',
            default: '%<attributes>s %<message>s',
            attributes: translate_attributes(attributes),
            message: error.message
          )
        end
        messages.uniq!
        messages
      end

      private

      def translate_attributes(keys)
        keys.map do |key|
          translate(key, scope: 'grape.errors.attributes', default: key.to_s)
        end.join(', ')
      end
    end
  end
end

1	# frozen_string_literal: true
2
3	module Grape	30✔
4	module Exceptions	30✔
5	class ValidationErrors < Base	30✔
6	include Enumerable	30✔
7
8	attr_reader :errors	30✔
9
10	def initialize(exceptions: [], headers: {})	30✔
11	@errors = exceptions.flat_map(&:errors).group_by(&:params)	8,553✔
12	super(message: full_messages.join(', '), status: 400, headers:)	8,553✔
13	end
14
15	def each	30✔
16	errors.each_pair do \|attribute, errors\|	8,697✔
17	errors.each do \|error\|	10,619✔
18	yield attribute, error	11,267✔
19	end
20	end
21	end
22
23	def as_json(**_opts)	30✔
24	errors.map do \|k, v\|	48✔
25	{
26	params: k,	48✔
27	messages: v.map(&:to_s)
28	}
29	end
30	end
31
32	def to_json(*_opts)	30✔
UNCOV 33	as_json.to_json	×
34	end
35
36	def full_messages	30✔
37	messages = map do \|attributes, error\|	8,601✔
38	translate(	11,171✔
39	:format,
40	scope: 'grape.errors',
41	default: '%<attributes>s %<message>s',
42	attributes: translate_attributes(attributes),
43	message: error.message
44	)
45	end
46	messages.uniq!	8,601✔
47	messages	8,601✔
48	end
49
50	private	30✔
51
52	def translate_attributes(keys)	30✔
53	keys.map do \|key\|	11,171✔
54	translate(key, scope: 'grape.errors.attributes', default: key.to_s)	12,995✔
55	end.join(', ')
56	end
57	end
58	end
59	end

ruby-grape / grape / 26721499467

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