Merge branch '38008-remove-deprecated-caching-class' into 'master'

Remove deprecated caching class

Closes #38008

See merge request gitlab-org/gitlab!23893

lib/gitlab/diff/deprecated_highlight_cache.rb

-# frozen_string_literal: true
-#
-module Gitlab
-  module Diff
-    class DeprecatedHighlightCache
-      delegate :diffable, to: :@diff_collection
-      delegate :diff_options, to: :@diff_collection
-
-      def initialize(diff_collection, backend: Rails.cache)
-        @backend = backend
-        @diff_collection = diff_collection
-      end
-
-      # - Reads from cache
-      # - Assigns DiffFile#highlighted_diff_lines for cached files
-      def decorate(diff_file)
-        if content = read_file(diff_file)
-          diff_file.highlighted_diff_lines = content.map do |line|
-            Gitlab::Diff::Line.init_from_hash(line)
-          end
-        end
-      end
-
-      # It populates a Hash in order to submit a single write to the memory
-      # cache. This avoids excessive IO generated by N+1's (1 writing for
-      # each highlighted line or file).
-      def write_if_empty
-        return if cached_content.present?
-
-        @diff_collection.diff_files.each do |diff_file|
-          next unless cacheable?(diff_file)
-
-          diff_file_id = diff_file.file_identifier
-
-          cached_content[diff_file_id] = diff_file.highlighted_diff_lines.map(&:to_hash)
-        end
-
-        cache.write(key, cached_content, expires_in: 1.week)
-      end
-
-      def clear
-        cache.delete(key)
-      end
-
-      def key
-        [diffable, 'highlighted-diff-files', Gitlab::Diff::Line::SERIALIZE_KEYS, diff_options]
-      end
-
-      private
-
-      def read_file(diff_file)
-        cached_content[diff_file.file_identifier]
-      end
-
-      def cache
-        @backend
-      end
-
-      def cached_content
-        @cached_content ||= cache.read(key) || {}
-      end
-
-      def cacheable?(diff_file)
-        diffable.present? && diff_file.text? && diff_file.diffable?
-      end
-    end
-  end
-end

lib/gitlab/diff/highlight_cache.rb

@@ -57,17 +57,6 @@ module Gitlab
 
       private
 
-      # We create a Gitlab::Diff::DeprecatedHighlightCache here in order to
-      #   expire deprecated cache entries while we make the transition. This can
-      #   be removed when :hset_redis_diff_caching is fully launched.
-      # See https://gitlab.com/gitlab-org/gitlab/issues/38008
-      #
-      def deprecated_cache
-        strong_memoize(:deprecated_cache) do
-          Gitlab::Diff::DeprecatedHighlightCache.new(@diff_collection)
-        end
-      end
-
       def cacheable_files
         strong_memoize(:cacheable_files) do
           diff_files.select { |file| cacheable?(file) && read_file(file).nil? }
@@ -104,10 +93,6 @@ module Gitlab
         #
         clear_memoization(:cached_content)
         clear_memoization(:cacheable_files)
-
-        # Clean up any deprecated hash entries
-        #
-        deprecated_cache.clear
       end
 
       def file_paths

spec/lib/gitlab/diff/deprecated_highlight_cache_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-describe Gitlab::Diff::DeprecatedHighlightCache do
-  let(:merge_request) { create(:merge_request_with_diffs) }
-
-  subject(:cache) { described_class.new(merge_request.diffs, backend: backend) }
-
-  describe '#decorate' do
-    let(:backend) { double('backend').as_null_object }
-
-    # Manually creates a Diff::File object to avoid triggering the cache on
-    # the FileCollection::MergeRequestDiff
-    let(:diff_file) do
-      diffs = merge_request.diffs
-      raw_diff = diffs.diffable.raw_diffs(diffs.diff_options.merge(paths: ['CHANGELOG'])).first
-      Gitlab::Diff::File.new(raw_diff,
-                             repository: diffs.project.repository,
-                             diff_refs: diffs.diff_refs,
-                             fallback_diff_refs: diffs.fallback_diff_refs)
-    end
-
-    it 'does not calculate highlighting when reading from cache' do
-      cache.write_if_empty
-      cache.decorate(diff_file)
-
-      expect_any_instance_of(Gitlab::Diff::Highlight).not_to receive(:highlight)
-
-      diff_file.highlighted_diff_lines
-    end
-
-    it 'assigns highlighted diff lines to the DiffFile' do
-      cache.write_if_empty
-      cache.decorate(diff_file)
-
-      expect(diff_file.highlighted_diff_lines.size).to be > 5
-    end
-
-    it 'submits a single reading from the cache' do
-      cache.decorate(diff_file)
-      cache.decorate(diff_file)
-
-      expect(backend).to have_received(:read).with(cache.key).once
-    end
-  end
-
-  describe '#write_if_empty' do
-    let(:backend) { double('backend', read: {}).as_null_object }
-
-    it 'submits a single writing to the cache' do
-      cache.write_if_empty
-      cache.write_if_empty
-
-      expect(backend).to have_received(:write).with(cache.key,
-                                                    hash_including('CHANGELOG-false-false-false'),
-                                                    expires_in: 1.week).once
-    end
-  end
-
-  describe '#clear' do
-    let(:backend) { double('backend').as_null_object }
-
-    it 'clears cache' do
-      cache.clear
-
-      expect(backend).to have_received(:delete).with(cache.key)
-    end
-  end
-end

spec/lib/gitlab/diff/highlight_cache_spec.rb

@@ -135,16 +135,6 @@ describe Gitlab::Diff::HighlightCache, :clean_gitlab_redis_cache do
       expect { cache.send(:write_to_redis_hash, diff_hash) }
         .to change { Gitlab::Redis::Cache.with { |r| r.hgetall(cache_key) } }
     end
-
-    # Note that this spec and the code it confirms can be removed when
-    #   :hset_redis_diff_caching is fully launched.
-    #
-    it 'attempts to clear deprecated cache entries' do
-      expect_any_instance_of(Gitlab::Diff::DeprecatedHighlightCache)
-        .to receive(:clear).and_call_original
-
-      cache.send(:write_to_redis_hash, diff_hash)
-    end
   end
 
   describe '#clear' do