Add OR filtering for author username

This adds OR filtering of authors for issues, MRs, and epics

app/finders/issuable_finder.rb

@@ -88,7 +88,7 @@ class IssuableFinder
     end
 
     def valid_params
-      @valid_params ||= scalar_params + [array_params.merge(not: {})]
+      @valid_params ||= scalar_params + [array_params.merge(or: {}, not: {})]
     end
   end
 
@@ -377,6 +377,7 @@ class IssuableFinder
     Issuables::AuthorFilter.new(
       items,
       params: original_params,
+      or_filters_enabled: or_filters_enabled?,
       not_filters_enabled: not_filters_enabled?
     ).filter
   end
@@ -498,6 +499,12 @@ class IssuableFinder
     params[:non_archived].present? ? items.non_archived : items
   end
 
+  def or_filters_enabled?
+    strong_memoize(:or_filters_enabled) do
+      Feature.enabled?(:or_issuable_queries, feature_flag_scope, default_enabled: :yaml)
+    end
+  end
+
   def not_filters_enabled?
     strong_memoize(:not_filters_enabled) do
       Feature.enabled?(:not_issuable_queries, feature_flag_scope, default_enabled: :yaml)

app/finders/issuables/author_filter.rb

+# frozen_string_literal: true
+
 module Issuables
   class AuthorFilter < BaseFilter
     def filter
       filtered = by_author(issuables)
+      filtered = by_author_union(filtered)
       by_negated_author(filtered)
     end
 
     private
 
     def by_author(issuables)
-      if no_author?
-        issuables.where(author_id: nil)
-      elsif params[:author_id].present?
-        issuables.where(author_id: params[:author_id])
+      if params[:author_id].present?
+        issuables.authored(params[:author_id])
       elsif params[:author_username].present?
-        issuables.where(author_id: authors_by_username(params[:author_username]))
+        issuables.authored(User.by_username(params[:author_username]))
       else
         issuables
       end
     end
 
+    def by_author_union(issuables)
+      return issuables unless or_filters_enabled? && or_params&.fetch(:author_username).present?
+
+      issuables.authored(User.by_username(or_params[:author_username]))
+    end
+
     def by_negated_author(issuables)
-      return issuables unless not_params.present? && not_filters_enabled?
+      return issuables unless not_filters_enabled? && not_params.present?
 
       if not_params[:author_id].present?
-        issuables.where.not(author_id: not_params[:author_id])
+        issuables.not_authored(not_params[:author_id])
       elsif not_params[:author_username].present?
-        issuables.where.not(author_id: authors_by_username(not_params[:author_username]))
+        issuables.not_authored(User.by_username(not_params[:author_username]))
       else
         issuables
       end
     end
-
-    def no_author?
-      # author_id takes precedence over author_username
-      params[:author_id] == NONE || params[:author_username] == NONE
-    end
-
-    def authors_by_username(usernames)
-      User.where(username: usernames)
-    end
   end
 end

app/finders/issuables/base_filter.rb

+# frozen_string_literal: true
+
 module Issuables
   class BaseFilter
-    # This is used as a common filter for None / Any
-    FILTER_NONE = 'none'
-    FILTER_ANY = 'any'
-
-    # This is used in unassigning users
-    NONE = '0'
-
     attr_reader :issuables, :params
 
-    def initialize(issuables, params:, not_filters_enabled: false)
+    def initialize(issuables, params:, or_filters_enabled: false, not_filters_enabled: false)
       @issuables = issuables
       @params = params
+      @or_filters_enabled = or_filters_enabled
       @not_filters_enabled = not_filters_enabled
     end
 
@@ -21,10 +17,18 @@ module Issuables
 
     private
 
+    def or_params
+      params[:or]
+    end
+
     def not_params
       params[:not]
     end
 
+    def or_filters_enabled?
+      @or_filters_enabled
+    end
+
     def not_filters_enabled?
       @not_filters_enabled
     end

app/models/concerns/issuable.rb

@@ -86,6 +86,7 @@ module Issuable
     before_validation :truncate_description_on_import!
 
     scope :authored, ->(user) { where(author_id: user) }
+    scope :not_authored, ->(user) { where.not(author_id: user) }
     scope :recent, -> { reorder(id: :desc) }
     scope :of_projects, ->(ids) { where(project_id: ids) }
     scope :opened, -> { with_state(:opened) }

config/feature_flags/development/or_issuable_queries.yml

+---
+name: or_issuable_queries
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/54444
+rollout_issue_url:
+milestone: '13.10'
+type: development
+group: group::project management
+default_enabled: false

ee/spec/finders/epics_finder_spec.rb

@@ -105,6 +105,22 @@ RSpec.describe EpicsFinder do
           it 'returns all epics authored by the given user' do
             expect(epics(author_id: user.id)).to contain_exactly(epic2)
           end
+
+          context 'using OR' do
+            it 'returns all epics authored by any of the given users' do
+              expect(epics(or: { author_username: [epic2.author.username, epic3.author.username] })).to contain_exactly(epic2, epic3)
+            end
+
+            context 'when feature flag is disabled' do
+              before do
+                stub_feature_flags(or_issuable_queries: false)
+              end
+
+              it 'does not add any filter' do
+                expect(epics(or: { author_username: [epic2.author.username, epic3.author.username] })).to contain_exactly(epic1, epic2, epic3)
+              end
+            end
+          end
         end
 
         context 'by label' do

spec/finders/issues_finder_spec.rb

@@ -179,7 +179,8 @@ RSpec.describe IssuesFinder do
         end
       end
 
-      context 'filtering by author ID' do
+      context 'filtering by author' do
+        context 'by author ID' do
           let(:params) { { author_id: user2.id } }
 
           it 'returns issues created by that user' do
@@ -187,7 +188,26 @@ RSpec.describe IssuesFinder do
           end
         end
 
-      context 'filtering by not author ID' do
+        context 'using OR' do
+          let(:issue6) { create(:issue, project: project2) }
+          let(:params) { { or: { author_username: [issue3.author.username, issue6.author.username] } } }
+
+          it 'returns issues created by any of the given users' do
+            expect(issues).to contain_exactly(issue3, issue6)
+          end
+
+          context 'when feature flag is disabled' do
+            before do
+              stub_feature_flags(or_issuable_queries: false)
+            end
+
+            it 'does not add any filter' do
+              expect(issues).to contain_exactly(issue1, issue2, issue3, issue4, issue5, issue6)
+            end
+          end
+        end
+
+        context 'filtering by NOT author ID' do
           let(:params) { { not: { author_id: user2.id } } }
 
           it 'returns issues not created by that user' do
@@ -208,6 +228,7 @@ RSpec.describe IssuesFinder do
             expect(issues).to be_empty
           end
         end
+      end
 
       context 'filtering by milestone' do
         let(:params) { { milestone_title: milestone.title } }

spec/finders/merge_requests_finder_spec.rb

@@ -41,17 +41,39 @@ RSpec.describe MergeRequestsFinder do
         expect(merge_requests).to contain_exactly(merge_request1)
       end
 
-      it 'filters by nonexistent author ID and MR term using CTE for search' do
-        params = {
-          author_id: 'does-not-exist',
-          search: 'git',
-          attempt_group_search_optimizations: true
-        }
+      context 'filtering by author' do
+        subject(:merge_requests) { described_class.new(user, params).execute }
 
-        merge_requests = described_class.new(user, params).execute
+        context 'using OR' do
+          let(:params) { { or: { author_username: [merge_request1.author.username, merge_request2.author.username] } } }
+
+          before do
+            merge_request1.update!(author: create(:user))
+            merge_request2.update!(author: create(:user))
+          end
 
+          it 'returns merge requests created by any of the given users' do
+            expect(merge_requests).to contain_exactly(merge_request1, merge_request2)
+          end
+
+          context 'when feature flag is disabled' do
+            before do
+              stub_feature_flags(or_issuable_queries: false)
+            end
+
+            it 'does not add any filter' do
+              expect(merge_requests).to contain_exactly(merge_request1, merge_request2, merge_request3, merge_request4, merge_request5)
+            end
+          end
+        end
+
+        context 'with nonexistent author ID and MR term using CTE for search' do
+          let(:params) { { author_id: 'does-not-exist', search: 'git', attempt_group_search_optimizations: true } }
+
+          it 'returns no results' do
             expect(merge_requests).to be_empty
           end
+        end
 
         context 'filtering by not author ID' do
           let(:params) { { not: { author_id: user2.id } } }
@@ -62,11 +84,10 @@ RSpec.describe MergeRequestsFinder do
           end
 
           it 'returns merge requests not created by that user' do
-          merge_requests = described_class.new(user, params).execute
-
             expect(merge_requests).to contain_exactly(merge_request1, merge_request4, merge_request5)
           end
         end
+      end
 
       it 'filters by projects' do
         params = { projects: [project2.id, project3.id] }