Allow BoardListType.issues to filter by negated issueType in GraphQL

BoardListType.issues had the input argument to filter issues by negated
issueType but it had no effect if provided

Changelog: fixed

app/finders/issues_finder.rb

@@ -90,6 +90,12 @@ class IssuesFinder < IssuableFinder
     by_issue_types(issues)
   end
 
+  # Negates all params found in `negatable_params`
+  def filter_negated_items(items)
+    issues = super
+    by_negated_issue_types(issues)
+  end
+
   def by_confidential(items)
     return items if params[:confidential].nil?
 
@@ -121,6 +127,13 @@ class IssuesFinder < IssuableFinder
 
     items.with_issue_type(params[:issue_types])
   end
+
+  def by_negated_issue_types(items)
+    issue_type_params = Array(not_params[:issue_types]).map(&:to_s) & WorkItem::Type.base_types.keys
+    return items if issue_type_params.blank?
+
+    items.without_issue_type(issue_type_params)
+  end
 end
 
 IssuesFinder.prepend_mod_with('IssuesFinder')

app/models/issue.rb

@@ -127,6 +127,7 @@ class Issue < ApplicationRecord
       project: [:route, { namespace: :route }])
   }
   scope :with_issue_type, ->(types) { where(issue_type: types) }
+  scope :without_issue_type, ->(types) { where.not(issue_type: types) }
 
   scope :public_only, -> { where(confidential: false) }
   scope :confidential_only, -> { where(confidential: true) }

spec/graphql/resolvers/board_list_issues_resolver_spec.rb

@@ -57,6 +57,13 @@ RSpec.describe Resolvers::BoardListIssuesResolver do
         expect(result).to match_array([issue1])
       end
 
+      it 'filters issues by negated issue type' do
+        incident = create(:incident, project: project, labels: [label], relative_position: 15)
+        result = resolve_board_list_issues(args: { filters: { not: { types: ['issue'] } } })
+
+        expect(result).to contain_exactly(incident)
+      end
+
       it 'raises an exception if both assignee_username and assignee_wildcard_id are present' do
         expect do
           resolve_board_list_issues(args: { filters: { assignee_username: ['username'], assignee_wildcard_id: 'NONE' } })

spec/services/boards/issues/list_service_spec.rb

@@ -56,12 +56,23 @@ RSpec.describe Boards::Issues::ListService do
         it_behaves_like 'issues list service'
       end
 
-      context 'when filtering by type' do
-        it 'only returns the specified type' do
-          issue = create(:labeled_issue, project: project, milestone: m1, labels: [development, p1], issue_type: 'incident')
-          params = { board_id: board.id, id: list1.id, issue_types: 'incident' }
+      context 'when filtering' do
+        let_it_be(:incident) { create(:labeled_issue, project: project, milestone: m1, labels: [development, p1], issue_type: 'incident') }
 
-          expect(described_class.new(parent, user, params).execute).to eq [issue]
+        context 'when filtering by type' do
+          it 'only returns the specified type' do
+            params = { board_id: board.id, id: list1.id, issue_types: 'incident' }
+
+            expect(described_class.new(parent, user, params).execute).to eq [incident]
+          end
+        end
+
+        context 'when filtering by negated type' do
+          it 'only returns the specified type' do
+            params = { board_id: board.id, id: list1.id, not: { issue_types: ['issue'] } }
+
+            expect(described_class.new(parent, user, params).execute).to contain_exactly(incident)
+          end
         end
       end
     end