Fix error on empty query for Members API

changelogs/unreleased/41673-blank-query-members-api.yml

+---
+title: Fix error on empty query for Members API
+merge_request: 16235
+author:
+type: fixed

lib/api/members.rb

@@ -22,7 +22,7 @@ module API
           source = find_source(source_type, params[:id])
           users = source.users
-          users = users.merge(User.search(params[:query])) if params[:query]
+          users = users.merge(User.search(params[:query])) if params[:query].present?
           present paginate(users), with: Entities::Member, source: source
         end

lib/api/v3/members.rb

@@ -23,7 +23,7 @@ module API
             source = find_source(source_type, params[:id])
             users = source.users
-            users = users.merge(User.search(params[:query])) if params[:query]
+            users = users.merge(User.search(params[:query])) if params[:query].present?
             present paginate(users), with: ::API::Entities::Member, source: source
           end

spec/requests/api/members_spec.rb

@@ -65,6 +65,16 @@ describe API::Members do
         expect(json_response.count).to eq(1)
         expect(json_response.first['username']).to eq(master.username)
       end
+
+      it 'finds all members with no query specified' do
+        get api("/#{source_type.pluralize}/#{source.id}/members", developer), query: ''
+
+        expect(response).to have_gitlab_http_status(200)
+        expect(response).to include_pagination_headers
+        expect(json_response).to be_an Array
+        expect(json_response.count).to eq(2)
+        expect(json_response.map { |u| u['id'] }).to match_array [master.id, developer.id]
+      end
     end
   end

spec/requests/api/v3/members_spec.rb

@@ -58,6 +58,16 @@ describe API::V3::Members do
         expect(json_response.count).to eq(1)
         expect(json_response.first['username']).to eq(master.username)
       end
+
+      it 'finds all members with no query specified' do
+        get v3_api("/#{source_type.pluralize}/#{source.id}/members", developer), query: ''
+
+        expect(response).to have_gitlab_http_status(200)
+        expect(response).to include_pagination_headers
+        expect(json_response).to be_an Array
+        expect(json_response.count).to eq(2)
+        expect(json_response.map { |u| u['id'] }).to match_array [master.id, developer.id]
+      end
     end
   end