Fix get endpoint not returning members with minimal access

ee/spec/requests/api/members_spec.rb

@@ -114,6 +114,27 @@ RSpec.describe API::Members do
         end
       end
     end
+
+    describe 'GET /groups/:id/members/:user_id' do
+      context 'when minimal access role is available' do
+        it 'shows the member' do
+          stub_licensed_features(minimal_access_role: true)
+          get api("/groups/#{group.id}/members/#{minimal_access_member.user_id}", owner)
+
+          expect(response).to have_gitlab_http_status(:ok)
+          puts json_response
+          expect(json_response['id']).to eq(minimal_access_member.user_id)
+        end
+      end
+
+      context 'when minimal access role is not available' do
+        it 'does not show the member' do
+          get api("/groups/#{group.id}/members/#{minimal_access_member.id}", owner)
+
+          expect(response).to have_gitlab_http_status(:not_found)
+        end
+      end
+    end
   end
 
   context 'group members endpoint for group managed accounts' do

lib/api/members.rb

@@ -62,7 +62,7 @@ module API
         get ":id/members/:user_id" do
           source = find_source(source_type, params[:id])
 
-          members = source.members
+          members = source_members(source)
           member = members.find_by!(user_id: params[:user_id])
 
           present_members member