Return correct error messages / http statuses for the public API

app/services/issue_links/create_service.rb

@@ -6,7 +6,7 @@ module IssueLinks
 
     def execute
       if referenced_issues.blank?
-        return error('No Issue found for given params', 401)
+        return error('No Issue found for given params', 404)
       end
 
       create_issue_links

app/services/issue_links/destroy_service.rb

@@ -8,7 +8,7 @@ module IssueLinks
     end
 
     def execute
-      return error('Unauthorized', 401) unless permission_to_remove_relation?
+      return error('No Issue Link found', 404) unless permission_to_remove_relation?
 
       remove_relation
       create_notes

lib/api/issue_links.rb

@@ -31,7 +31,6 @@ module API
       end
       post ':id/issues/:issue_iid/links' do
         source_issue = find_project_issue(params[:issue_iid])
-
         target_issue = find_project_issue(declared_params[:target_issue_iid],
                                           declared_params[:target_project_id])
 
@@ -46,7 +45,7 @@ module API
 
           present issue_link, with: Entities::IssueLink
         else
-          not_found!
+          render_api_error!(result[:message], result[:http_status])
         end
       end
 
@@ -59,6 +58,9 @@ module API
       delete ':id/issues/:issue_iid/links/:issue_link_id' do
         issue_link = IssueLink.find(declared_params[:issue_link_id])
 
+        find_project_issue(params[:issue_iid])
+        find_project_issue(issue_link.target.iid.to_s, issue_link.target.project_id.to_s)
+
         result = ::IssueLinks::DestroyService
                    .new(issue_link, current_user)
                    .execute
@@ -66,7 +68,7 @@ module API
         if result[:status] == :success
           present issue_link, with: Entities::IssueLink
         else
-          not_found!
+          render_api_error!(result[:message], result[:http_status])
         end
       end
     end

spec/requests/api/issue_links_spec.rb

@@ -80,7 +80,7 @@ describe API::IssueLinks do
                target_project_id: unauthorized_project.id, target_issue_iid: target_issue.iid
 
           expect(response).to have_http_status(404)
-          expect(json_response['message']).to eq('404 Not Found')
+          expect(json_response['message']).to eq('No Issue found for given params')
         end
       end
 
@@ -158,7 +158,7 @@ describe API::IssueLinks do
           delete api("/projects/#{project.id}/issues/#{issue.iid}/links/#{issue_link.id}", user)
 
           expect(response).to have_http_status(404)
-          expect(json_response['message']).to eq('404 Not Found')
+          expect(json_response['message']).to eq('No Issue Link found')
         end
       end
 
@@ -180,7 +180,7 @@ describe API::IssueLinks do
           delete api("/projects/#{project.id}/issues/#{issue.iid}/links/#{issue_link.id}", user)
 
           expect(response).to have_http_status(404)
-          expect(json_response['message']).to eq('404 Not Found')
+          expect(json_response['message']).to eq('404 Project Not Found')
         end
       end
 

spec/requests/projects/issue_links_controller_spec.rb

@@ -73,7 +73,7 @@ describe Projects::IssueLinksController do
 
           list_service_response = IssueLinks::ListService.new(issue, user).execute
 
-          expect(response).to have_http_status(401)
+          expect(response).to have_http_status(404)
           expect(json_response).to eq('message' => 'No Issue found for given params', 'issues' => list_service_response.as_json)
         end
       end
@@ -105,10 +105,10 @@ describe Projects::IssueLinksController do
         let(:referenced_issue) { create :issue }
         let(:user_role) { :developer }
 
-        it 'returns 401' do
+        it 'returns 404' do
           delete namespace_project_issue_link_path(issue_links_params(id: issue_link.id))
 
-          expect(response).to have_http_status(401)
+          expect(response).to have_http_status(404)
         end
       end
     end

spec/services/issue_links/create_service_spec.rb

@@ -25,7 +25,7 @@ describe IssueLinks::CreateService, service: true do
       end
 
       it 'returns error' do
-        is_expected.to eq(message: 'No Issue found for given params', status: :error, http_status: 401)
+        is_expected.to eq(message: 'No Issue found for given params', status: :error, http_status: 404)
       end
     end
 
@@ -35,7 +35,7 @@ describe IssueLinks::CreateService, service: true do
       end
 
       it 'returns error' do
-        is_expected.to eq(message: 'No Issue found for given params', status: :error, http_status: 401)
+        is_expected.to eq(message: 'No Issue found for given params', status: :error, http_status: 404)
       end
 
       it 'no relationship is created' do
@@ -53,7 +53,7 @@ describe IssueLinks::CreateService, service: true do
       it 'returns error' do
         target_issue.project.add_guest(user)
 
-        is_expected.to eq(message: 'No Issue found for given params', status: :error, http_status: 401)
+        is_expected.to eq(message: 'No Issue found for given params', status: :error, http_status: 404)
       end
 
       it 'no relationship is created' do

spec/services/issue_links/destroy_service_spec.rb

@@ -52,7 +52,7 @@ describe IssueLinks::DestroyService, service: true do
       end
 
       it 'returns error message' do
-        is_expected.to eq(message: 'Unauthorized', status: :error, http_status: 401)
+        is_expected.to eq(message: 'No Issue Link found', status: :error, http_status: 404)
       end
     end
   end