Add #project_default_branch to Vulnerability

ee/app/models/vulnerability.rb

@@ -60,6 +60,8 @@ def with_vulnerability_links
   scope :with_severities, -> (severities) { where(severity: severities) }
   scope :with_states, -> (states) { where(state: states) }
 
+  delegate :default_branch, to: :project, prefix: :project
+
   # There will only be one finding associated with a vulnerability for the foreseeable future
   def finding
     findings.first
@@ -72,8 +74,7 @@ def self.parent_class
   end
 
   def resolved_on_default_branch
-    default_branch = project.default_branch
-    latest_pipeline_for_default_branch = project.pipeline_for(default_branch)
+    latest_pipeline_for_default_branch = project.pipeline_for(project_default_branch)
     latest_pipeline_with_vulnerability = finding.pipelines.order(created_at: :desc).first
     latest_pipeline_with_vulnerability != latest_pipeline_for_default_branch
   end

ee/lib/ee/api/entities/vulnerability.rb

@@ -17,6 +17,7 @@ class Vulnerability < Grape::Entity
 
         expose :finding
         expose :resolved_on_default_branch
+        expose :project_default_branch
 
         expose :author_id
         expose :updated_by_id

ee/spec/models/vulnerability_spec.rb

@@ -172,6 +172,15 @@
     it { is_expected.to eq(finding.scanner_name) }
   end
 
+  describe '#project_default_branch' do
+    let_it_be(:project) { create(:project, :repository, :with_vulnerabilities) }
+    let_it_be(:vulnerability) { project.vulnerabilities.first }
+
+    subject { vulnerability.project_default_branch }
+
+    it { is_expected.to eq("master") }
+  end
+
   describe '#resolved_on_default_branch' do
     let_it_be(:project) { create(:project, :repository, :with_vulnerabilities) }
     let_it_be(:pipeline_with_vulnerability) { create(:ci_pipeline, project: project, sha: project.commit.id) }

tooling/overcommit/Gemfile.lock

@@ -72,4 +72,4 @@ DEPENDENCIES
   scss_lint (~> 0.56.0)
 
 BUNDLED WITH
-   1.17.3
+   2.1.4