Refactor Banzai reference filter caching

ee/lib/ee/banzai/filter/references/epic_reference_filter.rb

@@ -43,8 +43,6 @@ module EE
           end
           # rubocop: enable CodeReuse/ActiveRecord
 
-          private
-
           def parent_type
             :group
           end

ee/lib/ee/banzai/filter/references/iteration_reference_filter.rb

@@ -54,7 +54,7 @@ module EE
           end
 
           def parse_and_find_iteration(project_ref, namespace_ref, iteration_id, iteration_name)
-            project_path = full_project_path(namespace_ref, project_ref)
+            project_path = reference_cache.full_project_path(namespace_ref, project_ref)
 
             # Returns group if project is not found by path
             parent = parent_from_ref(project_path)

ee/lib/ee/banzai/filter/references/abstract_reference_filter.rb → ee/lib/ee/banzai/filter/references/reference_cache.rb

@@ -4,12 +4,14 @@ module EE
   module Banzai
     module Filter
       module References
-        module AbstractReferenceFilter
+        module ReferenceCache
           extend ::Gitlab::Utils::Override
 
           override :current_project_namespace_path
           def current_project_namespace_path
-            @current_project_namespace_path ||= (project&.namespace || group)&.full_path
+            strong_memoize(:current_project_namespace_path) do
+              (project&.namespace || group)&.full_path
+            end
           end
         end
       end

ee/lib/ee/banzai/filter/references/vulnerability_reference_filter.rb

@@ -53,8 +53,6 @@ module EE
             record.id.to_i
           end
 
-          private
-
           def parent_type
             :project
           end

lib/banzai/cross_project_reference.rb

@@ -17,7 +17,12 @@ module Banzai
       return context[:project] || context[:group] unless ref
       return context[:project] if context[:project]&.full_path == ref
 
-      Project.find_by_full_path(ref)
+      if reference_cache.cache_loaded?
+        # optimization to reuse the parent_per_reference query information
+        reference_cache.parent_per_reference[ref || reference_cache.current_parent_path]
+      else
+        Project.find_by_full_path(ref)
+      end
     end
   end
 end

lib/banzai/filter/references/abstract_reference_filter.rb

@@ -8,6 +8,12 @@ module Banzai
       class AbstractReferenceFilter < ReferenceFilter
         include CrossProjectReference
 
+        def initialize(doc, context = nil, result = nil)
+          super
+
+          @reference_cache = ReferenceCache.new(self, context)
+        end
+
         # REFERENCE_PLACEHOLDER is used for re-escaping HTML text except found
         # reference (which we replace with placeholder during re-scaping).  The
         # random number helps ensure it's pretty close to unique. Since it's a
@@ -112,6 +118,8 @@ module Banzai
         def call
           return doc unless project || group || user
 
+          reference_cache.load_reference_cache(nodes) if respond_to?(:parent_records)
+
           ref_pattern = object_reference_pattern
           link_pattern = object_class.link_reference_pattern
 
@@ -174,9 +182,9 @@ module Banzai
         def object_link_filter(text, pattern, link_content: nil, link_reference: false)
           references_in(text, pattern) do |match, id, project_ref, namespace_ref, matches|
             parent_path = if parent_type == :group
-                            full_group_path(namespace_ref)
+                            reference_cache.full_group_path(namespace_ref)
                           else
-                            full_project_path(namespace_ref, project_ref)
+                            reference_cache.full_project_path(namespace_ref, project_ref)
                           end
 
             parent = from_ref_cached(parent_path)
@@ -263,127 +271,6 @@ module Banzai
           text
         end
 
-        # Returns a Hash containing all object references (e.g. issue IDs) per the
-        # project they belong to.
-        def references_per_parent
-          @references_per ||= {}
-
-          @references_per[parent_type] ||= begin
-            refs = Hash.new { |hash, key| hash[key] = Set.new }
-            regex = [
-              object_class.link_reference_pattern,
-              object_class.reference_pattern
-            ].compact.reduce { |a, b| Regexp.union(a, b) }
-
-            nodes.each do |node|
-              node.to_html.scan(regex) do
-                path = if parent_type == :project
-                         full_project_path($~[:namespace], $~[:project])
-                       else
-                         full_group_path($~[:group])
-                       end
-
-                if ident = identifier($~)
-                  refs[path] << ident
-                end
-              end
-            end
-
-            refs
-          end
-        end
-
-        # Returns a Hash containing referenced projects grouped per their full
-        # path.
-        def parent_per_reference
-          @per_reference ||= {}
-
-          @per_reference[parent_type] ||= begin
-            refs = Set.new
-
-            references_per_parent.each do |ref, _|
-              refs << ref
-            end
-
-            find_for_paths(refs.to_a).index_by(&:full_path)
-          end
-        end
-
-        def relation_for_paths(paths)
-          klass = parent_type.to_s.camelize.constantize
-          result = klass.where_full_path_in(paths)
-          return result if parent_type == :group
-
-          result.includes(:namespace) if parent_type == :project
-        end
-
-        # Returns projects for the given paths.
-        def find_for_paths(paths)
-          if Gitlab::SafeRequestStore.active?
-            cache = refs_cache
-            to_query = paths - cache.keys
-
-            unless to_query.empty?
-              records = relation_for_paths(to_query)
-
-              found = []
-              records.each do |record|
-                ref = record.full_path
-                get_or_set_cache(cache, ref) { record }
-                found << ref
-              end
-
-              not_found = to_query - found
-              not_found.each do |ref|
-                get_or_set_cache(cache, ref) { nil }
-              end
-            end
-
-            cache.slice(*paths).values.compact
-          else
-            relation_for_paths(paths)
-          end
-        end
-
-        def current_parent_path
-          @current_parent_path ||= parent&.full_path
-        end
-
-        def current_project_namespace_path
-          @current_project_namespace_path ||= project&.namespace&.full_path
-        end
-
-        def records_per_parent
-          @_records_per_project ||= {}
-
-          @_records_per_project[object_class.to_s.underscore] ||= begin
-            hash = Hash.new { |h, k| h[k] = {} }
-
-            parent_per_reference.each do |path, parent|
-              record_ids = references_per_parent[path]
-
-              parent_records(parent, record_ids).each do |record|
-                hash[parent][record_identifier(record)] = record
-              end
-            end
-
-            hash
-          end
-        end
-
-        private
-
-        def full_project_path(namespace, project_ref)
-          return current_parent_path unless project_ref
-
-          namespace_ref = namespace || current_project_namespace_path
-          "#{namespace_ref}/#{project_ref}"
-        end
-
-        def refs_cache
-          Gitlab::SafeRequestStore["banzai_#{parent_type}_refs".to_sym] ||= {}
-        end
-
         def parent_type
           :project
         end
@@ -392,11 +279,9 @@ module Banzai
           parent_type == :project ? project : group
         end
 
-        def full_group_path(group_ref)
-          return current_parent_path unless group_ref
+        private
 
-          group_ref
-        end
+        attr_accessor :reference_cache
 
         def escape_with_placeholders(text, placeholder_data)
           escaped = escape_html_entities(text)
@@ -409,5 +294,3 @@ module Banzai
     end
   end
 end
-
-Banzai::Filter::References::AbstractReferenceFilter.prepend_if_ee('EE::Banzai::Filter::References::AbstractReferenceFilter')

lib/banzai/filter/references/commit_reference_filter.rb

@@ -19,7 +19,7 @@ module Banzai
         def find_object(project, id)
           return unless project.is_a?(Project) && project.valid_repo?
 
-          _, record = records_per_parent[project].detect { |k, _v| Gitlab::Git.shas_eql?(k, id) }
+          _, record = reference_cache.records_per_parent[project].detect { |k, _v| Gitlab::Git.shas_eql?(k, id) }
 
           record
         end
@@ -28,7 +28,7 @@ module Banzai
           return [] unless noteable.is_a?(MergeRequest)
 
           @referenced_merge_request_commit_shas ||= begin
-            referenced_shas = references_per_parent.values.reduce(:|).to_a
+            referenced_shas = reference_cache.references_per_parent.values.reduce(:|).to_a
             noteable.all_commit_shas.select do |sha|
               referenced_shas.any? { |ref| Gitlab::Git.shas_eql?(sha, ref) }
             end
@@ -66,12 +66,12 @@ module Banzai
           extras
         end
 
-        private
-
         def parent_records(parent, ids)
           parent.commits_by(oids: ids.to_a)
         end
 
+        private
+
         def noteable
           context[:noteable]
         end

lib/banzai/filter/references/design_reference_filter.rb

@@ -36,7 +36,7 @@ module Banzai
         self.object_class   = ::DesignManagement::Design
 
         def find_object(project, identifier)
-          records_per_parent[project][identifier]
+          reference_cache.records_per_parent[project][identifier]
         end
 
         def parent_records(project, identifiers)
@@ -59,15 +59,6 @@ module Banzai
           super.includes(:route, :namespace, :group)
         end
 
-        def parent_type
-          :project
-        end
-
-        # optimisation to reuse the parent_per_reference query information
-        def parent_from_ref(ref)
-          parent_per_reference[ref || current_parent_path]
-        end
-
         def url_for_object(design, project)
           path_options = { vueroute: design.filename }
           Gitlab::Routing.url_helpers.designs_project_issue_path(project, design.issue, path_options)

lib/banzai/filter/references/issuable_reference_filter.rb

@@ -9,11 +9,7 @@ module Banzai
         end
 
         def find_object(parent, iid)
-          records_per_parent[parent][iid]
-        end
-
-        def parent_from_ref(ref)
-          parent_per_reference[ref || current_parent_path]
+          reference_cache.records_per_parent[parent][iid]
         end
       end
     end

lib/banzai/filter/references/label_reference_filter.rb

@@ -17,7 +17,7 @@ module Banzai
           unescaped_html = unescape_html_entities(text).gsub(pattern) do |match|
             namespace = $~[:namespace]
             project = $~[:project]
-            project_path = full_project_path(namespace, project)
+            project_path = reference_cache.full_project_path(namespace, project)
             label = find_label_cached(project_path, $~[:label_id], $~[:label_name])
 
             if label
@@ -93,7 +93,7 @@ module Banzai
           parent = project || group
 
           if project || full_path_ref?(matches)
-            project_path    = full_project_path(matches[:namespace], matches[:project])
+            project_path    = reference_cache.full_project_path(matches[:namespace], matches[:project])
             parent_from_ref = from_ref_cached(project_path)
             reference       = parent_from_ref.to_human_reference(parent)
 

lib/banzai/filter/references/milestone_reference_filter.rb

@@ -67,7 +67,7 @@ module Banzai
         end
 
         def find_milestone(project_ref, namespace_ref, milestone_id, milestone_name)
-          project_path = full_project_path(namespace_ref, project_ref)
+          project_path = reference_cache.full_project_path(namespace_ref, project_ref)
 
           # Returns group if project is not found by path
           parent = parent_from_ref(project_path)

lib/banzai/filter/references/reference_cache.rb

+# frozen_string_literal: true
+
+module Banzai
+  module Filter
+    module References
+      class ReferenceCache
+        include Gitlab::Utils::StrongMemoize
+        include RequestStoreReferenceCache
+
+        def initialize(filter, context)
+          @filter = filter
+          @context = context
+        end
+
+        def load_reference_cache(nodes)
+          load_references_per_parent(nodes)
+          load_parent_per_reference
+          load_records_per_parent
+
+          @cache_loaded = true
+        end
+
+        # Loads all object references (e.g. issue IDs) per
+        # project/group they belong to.
+        def load_references_per_parent(nodes)
+          @references_per_parent ||= {}
+
+          @references_per_parent[parent_type] ||= begin
+            refs = Hash.new { |hash, key| hash[key] = Set.new }
+
+            nodes.each do |node|
+              node.to_html.scan(regex) do
+                path = if parent_type == :project
+                         full_project_path($~[:namespace], $~[:project])
+                       else
+                         full_group_path($~[:group])
+                       end
+
+                ident = filter.identifier($~)
+                refs[path] << ident if ident
+              end
+            end
+
+            refs
+          end
+        end
+
+        def references_per_parent
+          @references_per_parent[parent_type]
+        end
+
+        # Returns a Hash containing referenced projects grouped per their full
+        # path.
+        def load_parent_per_reference
+          @per_reference ||= {}
+
+          @per_reference[parent_type] ||= begin
+            refs = references_per_parent.keys.to_set
+
+            find_for_paths(refs.to_a).index_by(&:full_path)
+          end
+        end
+
+        def parent_per_reference
+          @per_reference[parent_type]
+        end
+
+        def load_records_per_parent
+          @_records_per_project ||= {}
+
+          @_records_per_project[filter.object_class.to_s.underscore] ||= begin
+            hash = Hash.new { |h, k| h[k] = {} }
+
+            parent_per_reference.each do |path, parent|
+              record_ids = references_per_parent[path]
+
+              filter.parent_records(parent, record_ids).each do |record|
+                hash[parent][filter.record_identifier(record)] = record
+              end
+            end
+
+            hash
+          end
+        end
+
+        def records_per_parent
+          @_records_per_project[filter.object_class.to_s.underscore]
+        end
+
+        def relation_for_paths(paths)
+          klass = parent_type.to_s.camelize.constantize
+          result = klass.where_full_path_in(paths)
+          return result if parent_type == :group
+
+          result.includes(namespace: :route) if parent_type == :project
+        end
+
+        # Returns projects for the given paths.
+        def find_for_paths(paths)
+          if Gitlab::SafeRequestStore.active?
+            cache = refs_cache
+            to_query = paths - cache.keys
+
+            unless to_query.empty?
+              records = relation_for_paths(to_query)
+
+              found = []
+              records.each do |record|
+                ref = record.full_path
+                get_or_set_cache(cache, ref) { record }
+                found << ref
+              end
+
+              not_found = to_query - found
+              not_found.each do |ref|
+                get_or_set_cache(cache, ref) { nil }
+              end
+            end
+
+            cache.slice(*paths).values.compact
+          else
+            relation_for_paths(paths)
+          end
+        end
+
+        def current_parent_path
+          strong_memoize(:current_parent_path) do
+            parent&.full_path
+          end
+        end
+
+        def current_project_namespace_path
+          strong_memoize(:current_project_namespace_path) do
+            project&.namespace&.full_path
+          end
+        end
+
+        def full_project_path(namespace, project_ref)
+          return current_parent_path unless project_ref
+
+          namespace_ref = namespace || current_project_namespace_path
+          "#{namespace_ref}/#{project_ref}"
+        end
+
+        def full_group_path(group_ref)
+          return current_parent_path unless group_ref
+
+          group_ref
+        end
+
+        def cache_loaded?
+          !!@cache_loaded
+        end
+
+        private
+
+        attr_accessor :filter, :context
+
+        delegate :project, :group, :parent, :parent_type, to: :filter
+
+        def regex
+          strong_memoize(:regex) do
+            [
+              filter.object_class.link_reference_pattern,
+              filter.object_class.reference_pattern
+            ].compact.reduce { |a, b| Regexp.union(a, b) }
+          end
+        end
+
+        def refs_cache
+          Gitlab::SafeRequestStore["banzai_#{parent_type}_refs".to_sym] ||= {}
+        end
+      end
+    end
+  end
+end
+
+Banzai::Filter::References::ReferenceCache.prepend_if_ee('EE::Banzai::Filter::References::ReferenceCache')

lib/banzai/filter/references/reference_filter.rb

@@ -97,6 +97,18 @@ module Banzai
           @nodes ||= each_node.to_a
         end
 
+        def object_class
+          self.class.object_class
+        end
+
+        def project
+          context[:project]
+        end
+
+        def group
+          context[:group]
+        end
+
         private
 
         # Returns a data attribute String to attach to a reference link
@@ -141,14 +153,6 @@ module Banzai
           needs :project unless skip_project_check?
         end
 
-        def project
-          context[:project]
-        end
-
-        def group
-          context[:group]
-        end
-
         def user
           context[:user]
         end
@@ -216,10 +220,6 @@ module Banzai
           node.is_a?(Nokogiri::XML::Element)
         end
 
-        def object_class
-          self.class.object_class
-        end
-
         def object_reference_pattern
           @object_reference_pattern ||= object_class.reference_pattern
         end

spec/lib/banzai/cross_project_reference_spec.rb

@@ -4,10 +4,12 @@ require 'spec_helper'
 
 RSpec.describe Banzai::CrossProjectReference do
   let(:including_class) { Class.new.include(described_class).new }
+  let(:reference_cache) { Banzai::Filter::References::ReferenceCache.new(including_class, {})}
 
   before do
     allow(including_class).to receive(:context).and_return({})
     allow(including_class).to receive(:parent_from_ref).and_call_original
+    allow(including_class).to receive(:reference_cache).and_return(reference_cache)
   end
 
   describe '#parent_from_ref' do
@@ -47,5 +49,18 @@ RSpec.describe Banzai::CrossProjectReference do
         expect(including_class.parent_from_ref('cross/reference')).to eq project2
       end
     end
+
+    context 'when reference cache is loaded' do
+      let(:project2) { double('referenced project') }
+
+      before do
+        allow(reference_cache).to receive(:cache_loaded?).and_return(true)
+        allow(reference_cache).to receive(:parent_per_reference).and_return({ 'cross/reference' => project2 })
+      end
+
+      it 'pulls from the reference cache' do
+        expect(including_class.parent_from_ref('cross/reference')).to eq project2
+      end
+    end
   end
 end

spec/lib/banzai/filter/references/abstract_reference_filter_spec.rb

@@ -8,18 +8,6 @@ RSpec.describe Banzai::Filter::References::AbstractReferenceFilter do
   let(:doc) { Nokogiri::HTML.fragment('') }
   let(:filter) { described_class.new(doc, project: project) }
 
-  describe '#references_per_parent' do
-    let(:doc) { Nokogiri::HTML.fragment("#1 #{project.full_path}#2 #2") }
-
-    it 'returns a Hash containing references grouped per parent paths' do
-      expect(described_class).to receive(:object_class).exactly(6).times.and_return(Issue)
-
-      refs = filter.references_per_parent
-
-      expect(refs).to match(a_hash_including(project.full_path => contain_exactly(1, 2)))
-    end
-  end
-
   describe '#data_attributes_for' do
     let_it_be(:issue) { create(:issue, project: project) }
 
@@ -32,74 +20,6 @@ RSpec.describe Banzai::Filter::References::AbstractReferenceFilter do
     end
   end
 
-  describe '#parent_per_reference' do
-    it 'returns a Hash containing projects grouped per parent paths' do
-      expect(filter).to receive(:references_per_parent)
-        .and_return({ project.full_path => Set.new([1]) })
-
-      expect(filter.parent_per_reference)
-        .to eq({ project.full_path => project })
-    end
-  end
-
-  describe '#find_for_paths' do
-    context 'with RequestStore disabled' do
-      it 'returns a list of Projects for a list of paths' do
-        expect(filter.find_for_paths([project.full_path]))
-          .to eq([project])
-      end
-
-      it "return an empty array for paths that don't exist" do
-        expect(filter.find_for_paths(['nonexistent/project']))
-          .to eq([])
-      end
-    end
-
-    context 'with RequestStore enabled', :request_store do
-      it 'returns a list of Projects for a list of paths' do
-        expect(filter.find_for_paths([project.full_path]))
-          .to eq([project])
-      end
-
-      context 'when no project with that path exists' do
-        it 'returns no value' do
-          expect(filter.find_for_paths(['nonexistent/project']))
-            .to eq([])
-        end
-
-        it 'adds the ref to the project refs cache' do
-          project_refs_cache = {}
-          allow(filter).to receive(:refs_cache).and_return(project_refs_cache)
-
-          filter.find_for_paths(['nonexistent/project'])
-
-          expect(project_refs_cache).to eq({ 'nonexistent/project' => nil })
-        end
-
-        context 'when the project refs cache includes nil values' do
-          before do
-            # adds { 'nonexistent/project' => nil } to cache
-            filter.from_ref_cached('nonexistent/project')
-          end
-
-          it "return an empty array for paths that don't exist" do
-            expect(filter.find_for_paths(['nonexistent/project']))
-              .to eq([])
-          end
-        end
-      end
-    end
-  end
-
-  describe '#current_parent_path' do
-    it 'returns the path of the current parent' do
-      doc = Nokogiri::HTML.fragment('')
-      filter = described_class.new(doc, project: project)
-
-      expect(filter.current_parent_path).to eq(project.full_path)
-    end
-  end
-
   context 'abstract methods' do
     describe '#find_object' do
       it 'raises NotImplementedError' do

spec/lib/banzai/filter/references/issue_reference_filter_spec.rb

@@ -470,24 +470,6 @@ RSpec.describe Banzai::Filter::References::IssueReferenceFilter do
     end
   end
 
-  describe '#records_per_parent' do
-    context 'using an internal issue tracker' do
-      it 'returns a Hash containing the issues per project' do
-        doc = Nokogiri::HTML.fragment('')
-        filter = described_class.new(doc, project: project)
-
-        expect(filter).to receive(:parent_per_reference)
-          .and_return({ project.full_path => project })
-
-        expect(filter).to receive(:references_per_parent)
-          .and_return({ project.full_path => Set.new([issue.iid]) })
-
-        expect(filter.records_per_parent)
-          .to eq({ project => { issue.iid => issue } })
-      end
-    end
-  end
-
   describe '.references_in' do
     let(:merge_request) { create(:merge_request) }
 

spec/lib/banzai/filter/references/reference_cache_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Banzai::Filter::References::ReferenceCache do
+  let_it_be(:project)  { create(:project) }
+  let_it_be(:project2) { create(:project) }
+  let_it_be(:issue1)   { create(:issue, project: project) }
+  let_it_be(:issue2)   { create(:issue, project: project) }
+  let_it_be(:issue3)   { create(:issue, project: project2) }
+  let_it_be(:doc)      { Nokogiri::HTML.fragment("#{issue1.to_reference} #{issue2.to_reference} #{issue3.to_reference(full: true)}") }
+
+  let(:filter_class) { Banzai::Filter::References::IssueReferenceFilter }
+  let(:filter)       { filter_class.new(doc, project: project) }
+  let(:cache)        { described_class.new(filter, { project: project }) }
+
+  describe '#load_references_per_parent' do
+    it 'loads references grouped per parent paths' do
+      cache.load_references_per_parent(filter.nodes)
+
+      expect(cache.references_per_parent).to eq({ project.full_path => [issue1.iid, issue2.iid].to_set,
+                                                  project2.full_path => [issue3.iid].to_set })
+    end
+  end
+
+  describe '#load_parent_per_reference' do
+    it 'returns a Hash containing projects grouped per parent paths' do
+      cache.load_references_per_parent(filter.nodes)
+      cache.load_parent_per_reference
+
+      expect(cache.parent_per_reference).to match({ project.full_path => project, project2.full_path => project2 })
+    end
+  end
+
+  describe '#load_records_per_parent' do
+    it 'returns a Hash containing projects grouped per parent paths' do
+      cache.load_references_per_parent(filter.nodes)
+      cache.load_parent_per_reference
+      cache.load_records_per_parent
+
+      expect(cache.records_per_parent).to match({ project => { issue1.iid => issue1, issue2.iid => issue2 },
+                                                  project2 => { issue3.iid => issue3 } })
+    end
+  end
+
+  describe '#initialize_reference_cache' do
+    it 'does not have an N+1 query problem with cross projects' do
+      doc_single = Nokogiri::HTML.fragment("#1")
+      filter_single = filter_class.new(doc_single, project: project)
+      cache_single = described_class.new(filter_single, { project: project })
+
+      control_count = ActiveRecord::QueryRecorder.new do
+        cache_single.load_references_per_parent(filter_single.nodes)
+        cache_single.load_parent_per_reference
+        cache_single.load_records_per_parent
+      end.count
+
+      # Since this is an issue filter that is not batching issue queries
+      # across projects, we have to account for that.
+      # 1 for both projects, 1 for issues in each project == 3
+      max_count = control_count + 1
+
+      expect do
+        cache.load_references_per_parent(filter.nodes)
+        cache.load_parent_per_reference
+        cache.load_records_per_parent
+      end.not_to exceed_query_limit(max_count)
+    end
+  end
+
+  describe '#find_for_paths' do
+    context 'with RequestStore disabled' do
+      it 'returns a list of Projects for a list of paths' do
+        expect(cache.find_for_paths([project.full_path]))
+          .to eq([project])
+      end
+
+      it 'return an empty array for paths that do not exist' do
+        expect(cache.find_for_paths(['nonexistent/project']))
+          .to eq([])
+      end
+    end
+
+    context 'with RequestStore enabled', :request_store do
+      it 'returns a list of Projects for a list of paths' do
+        expect(cache.find_for_paths([project.full_path]))
+          .to eq([project])
+      end
+
+      context 'when no project with that path exists' do
+        it 'returns no value' do
+          expect(cache.find_for_paths(['nonexistent/project']))
+            .to eq([])
+        end
+
+        it 'adds the ref to the project refs cache' do
+          project_refs_cache = {}
+          allow(cache).to receive(:refs_cache).and_return(project_refs_cache)
+
+          cache.find_for_paths(['nonexistent/project'])
+
+          expect(project_refs_cache).to eq({ 'nonexistent/project' => nil })
+        end
+      end
+    end
+  end
+
+  describe '#current_parent_path' do
+    it 'returns the path of the current parent' do
+      expect(cache.current_parent_path).to eq project.full_path
+    end
+  end
+
+  describe '#current_project_namespace_path' do
+    it 'returns the path of the current project namespace' do
+      expect(cache.current_project_namespace_path).to eq project.namespace.full_path
+    end
+  end
+
+  describe '#full_project_path' do
+    it 'returns current parent path when no ref specified' do
+      expect(cache.full_project_path('something', nil)).to eq cache.current_parent_path
+    end
+
+    it 'returns combined namespace and project ref' do
+      expect(cache.full_project_path('something', 'cool')).to eq 'something/cool'
+    end
+
+    it 'returns uses default namespace and project ref when namespace nil' do
+      expect(cache.full_project_path(nil, 'cool')).to eq "#{project.namespace.full_path}/cool"
+    end
+  end
+
+  describe '#full_group_path' do
+    it 'returns current parent path when no group ref specified' do
+      expect(cache.full_group_path(nil)).to eq cache.current_parent_path
+    end
+
+    it 'returns group ref' do
+      expect(cache.full_group_path('cool_group')).to eq 'cool_group'
+    end
+  end
+end